[redis]知识回顾之redis主从+哨兵搭建简要记录

1.先准备环境

家里的万年老爷机(120G的SSD，300G硬盘 )，手机热点下载，所以只能少利用空间资源，用virtualBox装centos7纯净版

其中要点：

1.virtualbox创建新机要用动态分配的虚拟磁盘(我选的默认8G)，virtual就300M并没有自带的linux，需要去下载centos7的镜像文件，最小版的大概1G，

个人用阿里云镜像站点更快：http://mirrors.aliyun.com/centos/7/isos/x86_64/

附官网的：http://isoredirect.centos.org/centos/7.4.1708/isos/x86_64/

（可以根据网址，改写url，一个个找自己的版本）

我是受够了公司低配外网老爷机机(4G内存+100G硬盘)centos可视化界面老崩，(吐槽公司外网机window无权限，linux只装centos居然还卡权限)

真心建议不要在centos完可视化，老老实实window/mac os工具生态丰富，linux上就命令行就行了。我在公司外网是要浏览器查资料+需要适当自住权限装软件测试代码（传统金融卡太严了:），太痛苦了。

 

2. 然后一路点点记得设置root账户密码，安全考虑应当封闭root账户远程登录，开启另外的账户远程登录权限，安全考虑ssh应当更改port，当然了学习阶段设置密码就行，被当作肉鸡了，“大侠再来一遍”就行。

3. 最后网络建议简单点就是使用 桥接网卡Adapter，就是跟台机/笔记本是同一个网段 共用的一个路由器，直接访问外网；

如果是NAT转发接口，那么就是通过虚拟出来的，是VirtulaBox Host-Only Network虚拟网卡下的局域网电脑，与主机无法直接互相ping通。需要通过这个VirtulaBox Host-Only Network来进行转发，才能互通有无，虚拟机中的电脑才能访问外网，配置很麻烦，但是会更安全，因为黑客要进来要层层剥开

非要配置NAT，比如实体机怎么ssh到虚拟机呢？

配置virtualBox网络转发：

（下面这张图，是我桥接网卡模式下的ip，不一样了，我懒得停了重启搞了麻烦）

最后，“NAT网卡转发”，下用 ssh user@主机IP -p 主机端口，  就会根据配置单端口转发规则，转到子系统Ip 和子系统端口去；

这个样子实在是麻烦，我要是访问外网，还得配80 443 脑壳疼，还是桥接模式吧，垃圾个人电脑，爱黑黑，大不了“大侠请重新来过”

2. 开始搭建redis

直接参考官网搭建:https://redis.io/download

也可以看中文网站：http://www.redis.cn/download.html 好几个不同域名的中文网站

详细参考：https://www.cnblogs.com/heqiuyong/p/10463334.html

就是，下载，解压，make编译，

听我的，网络不好，千万不要安装6.0以上，因为需要gcc 5.3 以上，centos7的是4.8需要装devtools 7以上，用该工具升级，yum升级不了，,我手机热点，，怎么也找不到官方的devtools离线包，索性放弃了。用redis5了

安装后记得 配置环境变量 vi /etc/profile 具体要看安装目录: export PATH=/usr/local/redis/bin/:$PATH

这个6.0及以上redis版本，怎么都搞不定，我就换成5.0版本了

配置文件 参考：https://www.redis.com.cn/linux-install-redis.html

3 redis主从+哨兵

参考：https://www.cnblogs.com/qinxu/p/9633418.html

https://www.cnblogs.com/leeSmall/p/8398401.html

大概就是如下模式：（这个也不是很对但是配置上形象一点，多个sentinel监控的是整个集群，master挂了，sentinel投票选一个sentinel来负责故障转移，然后选出来sentinel来决定那个slave升级为master）

简要流程：复制redis.conf文件 redis_master_7001.conf

修改端口port 7001,修改log文件，修改工作目录dir，修改持久化save，修改持久化rdb的文件名，修改持久化aof的文件名，修改redis读写密码authpass 修改redis主从复制的验证密码requirepass【两个密码最好一致免得混乱，sentinel哨兵中也有说需要两个密码一致】，修改优先级 slave-priority 【故障转移中哨兵优先选择优先级小的作为新master主节点】

然后复制 redis_master_7001.conf 为redis_slave_7002.conf文件

修改port 7002,【修改replicaof 原来的可能叫slaveof，可能因为国外防种族歧视，改为replica了】修改log文件，修改工作目录dir，修改持久化save，修改持久化rdb的文件名，修改持久化aof的文件名，修改redis读写密码authpass 修改redis主从复制的验证密码requirepass，修改优先级 slave-priority 

然后有复制修改为 redis_slave_7003.conf文件

再来复制修改sentinel.conf文件，

先修改一份port 71001,

              修改监听主节点：sentinel monitor mymaster 127.0.0.1 7001 2 #表示大于等于两个slave觉得它挂了就是挂了

              修改通讯密码： sentinel auth-pass mymaster 12345678     //连接主节点时的密码

             其它的也是修改 log文件，还有一个是故障转移启动脚本、通知客户端的配置。

然后复制刚才的conf文件，修改port、修改log等相关设置文件名

master_conf样例：（slave就是多一个replicaof 或者slaveof 找谁复制，然后是否开启只读）

# Redis configuration file example.
#
# Note that in order to read the configuration file, Redis must be
# started with the file path as first argument:
#
# ./redis-server /path/to/redis.conf

# Note on units: when memory size is needed, it is possible to specify
# it in the usual form of 1k 5GB 4M and so forth:
#
# 1k => 1000 bytes
# 1kb => 1024 bytes
# 1m => 1000000 bytes
# 1mb => 1024*1024 bytes
# 1g => 1000000000 bytes
# 1gb => 1024*1024*1024 bytes
#
# units are case insensitive so 1GB 1Gb 1gB are all the same.

################################## INCLUDES ###################################

# Include one or more other config files here.  This is useful if you
# have a standard template that goes to all Redis servers but also need
# to customize a few per-server settings.  Include files can include
# other files, so use this wisely.
#
# Notice option "include" won't be rewritten by command "CONFIG REWRITE"
# from admin or Redis Sentinel. Since Redis always uses the last processed
# line as value of a configuration directive, you'd better put includes
# at the beginning of this file to avoid overwriting config change at runtime.
#
# If instead you are interested in using includes to override configuration
# options, it is better to use include as the last line.
#
# include /path/to/local.conf
# include /path/to/other.conf

################################## MODULES #####################################

# Load modules at startup. If the server is not able to load modules
# it will abort. It is possible to use multiple loadmodule directives.
#
# loadmodule /path/to/my_module.so
# loadmodule /path/to/other_module.so

################################## NETWORK #####################################

# By default, if no "bind" configuration directive is specified, Redis listens
# for connections from all the network interfaces available on the server.
# It is possible to listen to just one or multiple selected interfaces using
# the "bind" configuration directive, followed by one or more IP addresses.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1
# bind 127.0.0.1 ::1
#
# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
# internet, binding to all the interfaces is dangerous and will expose the
# instance to everybody on the internet. So by default we uncomment the
# following bind directive, that will force Redis to listen only into
# the IPv4 loopback interface address (this means Redis will be able to
# accept connections only from clients running into the same computer it
# is running).
#
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bind 127.0.0.1

# Protected mode is a layer of security protection, in order to avoid that
# Redis instances left open on the internet are accessed and exploited.
#
# When protected mode is on and if:
#
# 1) The server is not binding explicitly to a set of addresses using the
#    "bind" directive.
# 2) No password is configured.OF文件时，如果启用下面的选项，则文件每生成32M数据会被同步
#
# The server only accepts connections from clients connecting from the
# IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain
# sockets.
#
# By default protected mode is enabled. You should disable it only if
# you are sure you want clients from other hosts to connect to Redis
# even if no authentication is configured, nor a specific set of interfaces
# are explicitly listed using the "bind" directive.
protected-mode yes

# Accept connections on the specified port, default is 6379 (IANA #815344).
# If port 0 is specified Redis will not listen on a TCP socket.
# 监听端口 default 6379
port 7001#

# TCP listen() backlog.
#
# In high requests-per-second environments you need an high backlog in order
# to avoid slow clients connections issues. Note that the Linux kernel
# will silently truncate it to the value of /proc/sys/net/core/somaxconn so
# make sure to raise both the value of somaxconn and tcp_max_syn_backlog
# in order to get the desired effect.
# TCP接收队列长度，受/proc/sys/net/core/somaxconn和tcp_max_syn_backlog这两个内核参数影响 default 511
tcp-backlog 511

# Unix socket.
#
# Specify the path for the Unix socket that will be used to listen for
# incoming connections. There is no default, so Redis will not listen
# on a unix socket when not specified.
#
# unixsocket /tmp/redis.sock
# unixsocketperm 700

# Close the connection after a client is idle for N seconds (0 to disable)
# 一个客户端空闲多少秒后关闭连接(0代表禁用，永不关闭) default 0禁用永不关闭
timeout 0

# TCP keepalive.
#
# If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence
# of communication. This is useful for two reasons:
#
# 1) Detect dead peers.
# 2) Take the connection alive from the point of view of network
#    equipment in the middle.
#
# On Linux, the specified value (in seconds) is the period used to send ACKs.
# Note that to close the connection the double of the time is needed.
# On other kernels the period depends on the kernel configuration.
#
# A reasonable value for this option is 300 seconds, which is the new
# Redis default starting with Redis 3.2.1.
# 如果非零，则设置SO_KEEPALIVE选项来向空闲连接的客户端发送ACk
tcp-keepalive 300

################################# GENERAL #####################################

# By default Redis does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
# 守护进程 default no
daemonize yes

# If you run Redis from upstart or systemd, Redis can interact with your
# supervision trpidfile /var/run/redis_6379.pidee. Options:
#   supervised no      - no supervision interaction
#   supervised upstart - signal upstart by putting Redis into SIGSTOP mode
#   supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
#   supervised auto    - detect upstart or systemd method based on
#                        UPSTART_JOB or NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal "process is ready."
#       They do not enable continuous liveness pings back to your supervisor.
supervised no

# If a pid file is specified, Redis writes it where specified at startup
# and removes it at exit.
#
# When the server runs non daemonized, no pid file is created if none is
# specified in the configuration. When the server is daemonized, the pid file
# is used even if not specified, defaulting to "/var/run/redis.pid".
#
# Creating a pid file is best effort: if Redis is not able to create it
# nothing bad happens, the server will start and run normally.
#pidfile /var/run/redis_6379.pid
pidfile /var/run/redis_master_7001.pid

# Specify the server verbosity level. 指定服务器调试等级
# This can be one of: 可能值：
# debug (a lot of information, useful for development/testing) （大量信息，对开发/测试有用）
# verbose (many rarely useful info, but not a mess like the debug level) （很多精简的有用信息，但是不像debug等级那么多）
# notice (moderately verbose, what you want in production probably) (适量的信息，基本上是你生产环境中需要的)
# warning (only very important / critical messages are logged) （只有很重要/很严重的信息会记录下来）
loglevel notice

# Specify the log file name. Also the empty string can be used to force
# Redis to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
# 指明日志文件名
logfile "/var/log/redis/redis_master_7001.log"

# To enable logging to the system logger, just set 'syslog-enabled' to yes,
# and optionally update the other syslog parameters to suit your needs.
# syslog-enabled no

# Specify the syslog identity.
# syslog-ident redis

# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# syslog-facility local0

# Set the number of databases. The default database is DB 0, you can select
# a different one on a per-connection basis using SELECT  where
# dbid is a number between 0 and 'databases'-1
# 设置数据库个数的上限 默认16个，但是建议生产中都是使用多个实例，而不是多个数据库，都是对key进行命名管理，不会去弄多个数据库的
databases 16

# By default Redis shows an ASCII art logo only when started to log to the
# standard output and if the standard output is a TTY. Basically this means
# that normally a logo is displayed only in interactive sessions.
#
# However it is possible to force the pre-4.0 behavior and always show a
# ASCII art logo in startup logs by setting the following option to yes.
always-show-logo yes

################################ SNAPSHOTTING  ################################
#
# Save the DB on disk:
#
#   save  
#
#   Will save the DB if both the given number of seconds and the given
#   number of write operations against the DB occurred.
#
#   In the example below the behaviour will be to save:
#   after 900 sec (15 min) if at least 1 key changed
#   after 300 sec (5 min) if at least 10 keys changed
#   after 60 sec if at least 10000 keys changed
#
#   Note: you can disable saving completely by commenting out all "save" lines.
#
#   It is also possible to remove all the previously configured save
#   points by adding a save directive with a single empty string argument
#   like in the following example:
#
#   save ""
# 会在指定秒数和数据变化次数之后把数据库写到磁盘上
# 900秒后，至少一次变更
save 900 1
# 300秒 至少10次变更
save 300 10
# 60秒 至少1000次变更
save 60 10000

# By default Redis will stop accepting writes if RDB snapshots are enabled
# (at least one save point) and the latest background save failed.
# This will make the user aware (in a hard way) that data is not persisting
# on disk properly, otherwise chances are that no one will notice and some
# disaster will happen.
#
# If the background saving process will start working again Redis will
# automatically allow writes again.
#
# However if you have setup your proper monitoring of the Redis server
# and persistence, you may want to disable this feature so that Redis will
# continue to work as usual even if there are problems with disk,
# permissions, and so forth.
# 默认如果开启RDB快照（至少一条save指令）并且最新的后台保存失败，Redis将会停止接受写操作
# 这将使用户知道数据没有正确的持久化到硬盘，否则可能没人注意到并且造成一些灾难
stop-writes-on-bgsave-error yes

# Compress string objects using LZF when dump .rdb databases?
# For default that's set to 'yes' as it's almost always a win.
# If you want to save some CPU in the saving child set it to 'no' but
# the dataset will likely be bigger if you have compressible values or keys.
# 当导出.rdb数据库时是否用LZF压缩字符串对象
rdbcompression yes

# Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
# This makes the format more resistant to corruption but there is a performance
# hit to pay (around 10%) when saving and loading RDB files, so you can disable it
# for maximum performances.
#
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
# 版本5的RDB有一个CRC64算法的校验和放在了文件的最后，这将使文件格式更加可靠
rdbchecksum yes

# The filename where to dump the DB
# 持久化数据库的文件名 default dump.rdb
dbfilename "dump_master_7001.rdb"

# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
#dir ./
#工作目录
dir /opt/redis-5.0.10/conf/redis_master

################################# REPLICATION #################################

# Master-Replica replication. Use replicaof to make a Redis instance a copy of
# another Redis server. A few things to understand ASAP about Redis replication.
#
#   +------------------+      +---------------+
#   |      Master      | ---> |    Replica    |
#   | (receive writes) |      |  (exact copy) |
#   +------------------+      +---------------+
#
# 1) Redis replication is asynchronous, but you can configure a master to
#    stop accepting writes if it appears to be not connected with at least
#    a given number of replicas.
# 2) Redis replicas are able to perform a partial resynchronization with the
#    master if the replication link is lost for a relatively small amount of
#    time. You may want to configure the replication backlog size (see the next
#    sections of this file) with a sensible value depending on your needs.
# 3) Replication is automatic and does not need user intervention. After a
#    network partition replicas automatically try to reconnect to masters
#    and resynchronize with them.
#
# replicaof  

# If the master is password protected (using the "requirepass" configuration
# directive below) it is possible to tell the replica to authenticate before
# starting the replication synchronization process, otherwise the master will
# refuse the replica request.
# 
# 当master服务设置了密码保护时，slaver服务连接master的密码
# masterauth 
masterauth [email protected]

# When a replica loses its connection with the master, or when the replication
# is still in progress, the replica can act in two different ways:
# 当一个slave失去和mater的连接，或者同步正在进行中，slave的行为可以有两种：
#
# 1) if replica-serve-stale-data is set to 'yes' (the default) the replica will
#    still reply to client requests, possibly with out of date data, or the
#    data set may just be empty if this is the first synchronization.
#    如果slave-serve-stale-data 设置为 "yes"(默认值)，slave会继续响应客户端请求，
#    可能是正常数据，或者是过时了的数据，也可能是还没活得值的空数据
     
#
# 2) if replica-serve-stale-data is set to 'no' the replica will reply with
#    an error "SYNC with master in progress" to all the kind of commands
#    but to INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG,
#    SUBSCRIBE, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB,
#    COMMAND, POST, HOST: and LATENCY.
#    如果 slave-serve-stale-data 设置为 "no",slave会回复"正从master同步(SYNC with mater in progress)
#     "来处理各种请求，除了INFO和SLAVEOF命令
#
replica-serve-stale-data yes

# You can configure a replica instance to accept writes or not. Writing against
# a replica instance may be useful to store some ephemeral data (because data
# written on a replica will be easily deleted after resync with the master) but
# may also cause problems if clients are writing to it because of a
# misconfiguration.
#
# Since Redis 2.6 by default replicas are read-only.
#
# Note: read only replicas are not designed to be exposed to untrusted clients
# on the internet. It's just a protection layer against misuse of the instance.
# Still a read only replica exports by default all the administrative commands
# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
# security of read only replicas using 'rename-command' to shadow all the
# administrative / dangerous commands.
# 你可以配置salve实例是否接受写操作。可写的slave实例可能对存储临时数据比较有用(因为写入salve
# 的数据在同master同步之后将很容易被删除
replica-read-only yes

# Replication SYNC strategy: disk or socket.
#
# -------------------------------------------------------
# WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY
# -------------------------------------------------------
#
# New replicas and reconnecting replicas that are not able to continue the replication
# process just receiving differences, need to do what is called a "full
# synchronization". An RDB file is transmitted from the master to the replicas.
# The transmission can happen in two different ways:
#
# 1) Disk-backed: The Redis master creates a new process that writes the RDB
#                 file on disk. Later the file is transferred by the parent
#                 process to the replicas incrementally.
# 2) Diskless: The Redis master creates a new process that directly writes the
#              RDB file to replica sockets, without touching the disk at all.
#
# With disk-backed replication, while the RDB file is generated, more replicas
# can be queued and served with the RDB file as soon as the current child producing
# the RDB file finishes its work. With diskless replication instead once
# the transfer starts, new replicas arriving will be queued and a new transfer
# will start when the current one terminates.
#
# When diskless replication is used, the master waits a configurable amount of
# time (in seconds) before starting the transfer in the hope that multiple replicas
# will arrive and the transfer can be parallelized.
#
# With slow disks and fast (large bandwidth) networks, diskless replication
# works better.
repl-diskless-sync no

# When diskless replication is enabled, it is possible to configure the delay
# the server waits in order to spawn the child that transfers the RDB via socket
# to the replicas.
#
# This is important since once the transfer starts, it is not possible to serve
# new replicas arriving, that will be queued for the next RDB transfer, so the server
# waits a delay in order to let more replicas arrive.
#
# The delay is specified in seconds, and by default is 5 seconds. To disable
# it entirely just set it to 0 seconds and the transfer will start ASAP.
repl-diskless-sync-delay 5

# Replicas send PINGs to server in a predefined interval. It's possible to change
# this interval with the repl_ping_replica_period option. The default value is 10
# seconds.
#
# repl-ping-replica-period 10

# The following option sets the replication timeout for:
#
# 1) Bulk transfer I/O during SYNC, from the point of view of replica.
# 2) Master timeout from the point of view of replicas (data, pings).
# 3) Replica timeout from the point of view of masters (REPLCONF ACK pings).
#
# It is important to make sure that this value is greater than the value
# specified for repl-ping-replica-period otherwise a timeout will be detected
# every time there is low traffic between the master and the replica.
#
# repl-timeout 60

# Disable TCP_NODELAY on the replica socket after SYNC?
#
# If you select "yes" Redis will use a smaller number of TCP packets and
# less bandwidth to send data to replicas. But this can add a delay for
# the data to appear on the replica side, up to 40 milliseconds with
# Linux kernels using a default configuration.
#
# If you select "no" the delay for data to appear on the replica side will
# be reduced but more bandwidth will be used for replication.
#
# By default we optimize for low latency, but in very high traffic conditions
# or when the master and replicas are many hops away, turning this to "yes" may
# be a good idea.
# 是否在slave套接字发送SYNC之后禁用 TCP_NODELAY？
# 如果你选择“yes”Redis将使用更少的TCP包和带宽来向slaves发送数据。但是这将使数据传输到slave
# 上有延迟，Linux内核的默认配置会达到40毫秒
# 如果你选择了 "no" 数据传输到salve的延迟将会减少但要使用更多的带宽
repl-disable-tcp-nodelay no

# Set the replication backlog size. The backlog is a buffer that accumulates
# replica data when replicas are disconnected for some time, so that when a replica
# wants to reconnect again, often a full resync is not needed, but a partial
# resync is enough, just passing the portion of data the replica missed while
# disconnected.
#
# The bigger the replication backlog, the longer the time the replica can be
# disconnected and later be able to perform a partial resynchronization.
#
# The backlog is only allocated once there is at least a replica connected.
#
# repl-backlog-size 1mb

# After a master has no longer connected replicas for some time, the backlog
# will be freed. The following option configures the amount of seconds that
# need to elapse, starting from the time the last replica disconnected, for
# the backlog buffer to be freed.
#
# Note that replicas never free the backlog for timeout, since they may be
# promoted to masters later, and should be able to correctly "partially
# resynchronize" with the replicas: hence they should always accumulate backlog.
#
# A value of 0 means to never release the backlog.
#
# repl-backlog-ttl 3600

# The replica priority is an integer number published by Redis in the INFO output.
# It is used by Redis Sentinel in order to select a replica to promote into a
# master if the master is no longer working correctly.
#
# A replica with a low priority number is considered better for promotion, so
# for instance if there are three replicas with priority 10, 100, 25 Sentinel will
# pick the one with priority 10, that is the lowest.
#
# However a special priority of 0 marks the replica as not able to perform the
# role of master, so a replica with priority of 0 will never be selected by
# Redis Sentinel for promotion.
#
# By default the priority is 100.
# slave的优先级是一个整数展示在Redis的Info输出中。如果master不再正常工作了，哨兵将用它来
# 选择一个slave提升=升为master。
# 优先级数字小的salve会优先考虑提升为master，所以例如有三个slave优先级分别为10，100，25，
# 哨兵将挑选优先级最小数字为10的slave。
# 0作为一个特殊的优先级，标识这个slave不能作为master，所以一个优先级为0的slave永远不会被
# 哨兵挑选提升为master
replica-priority 100

# It is possible for a master to stop accepting writes if there are less than
# N replicas connected, having a lag less or equal than M seconds.
#
# The N replicas need to be in "online" state.
#
# The lag in seconds, that must be <= the specified value, is calculated from
# the last ping received from the replica, that is usually sent every second.
#
# This option does not GUARANTEE that N replicas will accept the write, but
# will limit the window of exposure for lost writes in case not enough replicas
# are available, to the specified number of seconds.
#
# For example to require at least 3 replicas with a lag <= 10 seconds use:
#
# min-replicas-to-write 3
# min-replicas-max-lag 10
#
# Setting one or the other to 0 disables the feature.
#
# By default min-replicas-to-write is set to 0 (feature disabled) and
# min-replicas-max-lag is set to 10.

# A Redis master is able to list the address and port of the attached
# replicas in different ways. For example the "INFO replication" section
# offers this information, which is used, among other tools, by
# Redis Sentinel in order to discover replica instances.
# Another place where this info is available is in the output of the
# "ROLE" command of a master.
#
# The listed IP and address normally reported by a replica is obtained
# in the following way:
#
#   IP: The address is auto detected by checking the peer address
#   of the socket used by the replica to connect with the master.
#
#   Port: The port is communicated by the replica during the replication
#   handshake, and is normally the port that the replica is using to
#   listen for connections.
#
# However when port forwarding or Network Address Translation (NAT) is
# used, the replica may be actually reachable via different IP and port
# pairs. The following two options can be used by a replica in order to
# report to its master a specific set of IP and port, so that both INFO
# and ROLE will report those values.
#
# There is no need to use both the options if you need to override just
# the port or the IP address.
#
# replica-announce-ip 5.5.5.5
# replica-announce-port 1234

################################## SECURITY ###################################

# Require clients to issue AUTH  before processing any other
# commands.  This might be useful in environments in which you do not trust
# others with access to the host running redis-server.
#
# This should stay commented out for backward compatibility and because most
# people do not need auth (e.g. they run their own servers).
#
# Warning: since Redis is pretty fast an outside user can try up to
# 150k passwords per second against a good box. This means that you should
# use a very strong password otherwise it will be very easy to break.
#
# requirepass foobared
# 密码验证
# 警告：因为Redis太快了，所以外面的人可以尝试每秒150k的密码来试图破解密码。这意味着你需要
# 一个高强度的密码，否则破解太容易了
requirepass [email protected]

# Command renaming.
#
# It is possible to change the name of dangerous commands in a shared
# environment. For instance the CONFIG command may be renamed into something
# hard to guess so that it will still be available for internal-use tools
# but not available for general clients.
#
# Example:
#
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#
# It is also possible to completely kill a command by renaming it into
# an empty string:
#
# rename-command CONFIG ""
#
# Please note that changing the name of commands that are logged into the
# AOF file or transmitted to replicas may cause problems.

################################### CLIENTS ####################################

# Set the max number of connected clients at the same time. By default
# this limit is set to 10000 clients, however if the Redis server is not
# able to configure the process file limit to allow for the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (as Redis reserves a few file descriptors for internal uses).
#
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#
# maxclients 10000

############################## MEMORY MANAGEMENT ################################

# Set a memory usage limit to the specified amount of bytes.
# When the memory limit is reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPUSH, and so on, and will continue
# to reply to read-only commands like GET.
#
# This option is usually useful when using Redis as an LRU or LFU cache, or to
# set a hard memory limit for an instance (using the 'noeviction' policy).
#
# WARNING: If you have replicas attached to an instance with maxmemory on,
# the size of the output buffers needed to feed the replicas are subtracted
# from the used memory count, so that network problems / resyncs will
# not trigger a loop where keys are evicted, and in turn the output
# buffer of replicas is full with DELs of keys evicted triggering the deletion
# of more keys, and so forth until the database is completely emptied.
#
# In short... if you have replicas attached it is suggested that you set a lower
# limit for maxmemory so that there is some free RAM on the system for replica
# output buffers (but this is not needed if the policy is 'noeviction').
#
# maxmemory 
# redis实例最大占用内存，不要用比设置的上限更多的内存。一旦内存使用达到上限，Redis会根据选定的回收策略（参见：
# maxmemmory-policy）删除key  因为要弄成主从哨兵模式，弄少点，没台30M，共3台实例吧
maxmemory 30720000

# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select among five behaviors:
#
# volatile-lru -> Evict using approximated LRU among the keys with an expire set.
# allkeys-lru -> Evict any key using approximated LRU.
# volatile-lfu -> Evict using approximated LFU among the keys with an expire set.
# allkeys-lfu -> Evict any key using approximated LFU.
# volatile-random -> Remove a random key among the ones with an expire set.
# allkeys-random -> Remove a random key, any key.
# volatile-ttl -> Remove the key with the nearest expire time (minor TTL)
# noeviction -> Don't evict anything, just return an error on write operations.
#
# LRU means Least Recently Used
# LFU means Least Frequently Used
#
# Both LRU, LFU and volatile-ttl are implemented using approximated
# randomized algorithms.
#
# Note: with any of the above policies, Redis will return an error on write
#       operations, when there are no suitable keys for eviction.
#
#       At the date of writing these commands are: set setnx setex append
#       incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
#       sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
#       zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
#       getset mset msetnx exec sort
#
# The default is:
#
# maxmemory-policy noeviction
# 最大内存策略：如果达到内存限制了，Redis如何选择删除key。你可以在下面五个行为里选：
# volatile-lru -> 根据LRU算法删除带有过期时间的key。
# allkeys-lru -> 根据LRU算法删除任何key。
# volatile-random -> 根据过期设置来随机删除key, 具备过期时间的key。 
# allkeys->random -> 无差别随机删, 任何一个key。 
# volatile-ttl -> 根据最近过期时间来删除（辅以TTL）, 这是对于有过期时间的key 
# noeviction -> 谁也不删，直接在写操作时返回错误。
# maxmemory-policy allkeys-lru

# LRU, LFU and minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can tune it for speed or
# accuracy. For default Redis will check five keys and pick the one that was
# used less recently, you can change the sample size using the following
# configuration directive.
#
# The default of 5 produces good enough results. 10 Approximates very closely
# true LRU but costs more CPU. 3 is faster but not very accurate.
#
# maxmemory-samples 5

# Starting from Redis 5, by default a replica will ignore its maxmemory setting
# (unless it is promoted to master after a failover or manually). It means
# that the eviction of keys will be just handled by the master, sending the
# DEL commands to the replica as keys evict in the master side.
#
# This behavior ensures that masters and replicas stay consistent, and is usually
# what you want, however if your replica is writable, or you want the replica to have
# a different memory setting, and you are sure all the writes performed to the
# replica are idempotent, then you may change this default (but be sure to understand
# what you are doing).
#
# Note that since the replica by default does not evict, it may end using more
# memory than the one set via maxmemory (there are certain buffers that may
# be larger on the replica, or data structures may sometimes take more memory and so
# forth). So make sure you monitor your replicas and make sure they have enough
# memory to never hit a real out-of-memory condition before the master hits
# the configured maxmemory setting.
#
# replica-ignore-maxmemory yes

############################# LAZY FREEING ####################################

# Redis has two primitives to delete keys. One is called DEL and is a blocking
# deletion of the object. It means that the server stops processing new commands
# in order to reclaim all the memory associated with an object in a synchronous
# way. If the key deleted is associated with a small object, the time needed
# in order to execute the DEL command is very small and comparable to most other
# O(1) or O(log_N) commands in Redis. However if the key is associated with an
# aggregated value containing millions of elements, the server can block for
# a long time (even seconds) in order to complete the operation.
#
# For the above reasons Redis also offers non blocking deletion primitives
# such as UNLINK (non blocking DEL) and the ASYNC option of FLUSHALL and
# FLUSHDB commands, in order to reclaim memory in background. Those commands
# are executed in constant time. Another thread will incrementally free the
# object in the background as fast as possible.
#
# DEL, UNLINK and ASYNC option of FLUSHALL and FLUSHDB are user-controlled.
# It's up to the design of the application to understand when it is a good
# idea to use one or the other. However the Redis server sometimes has to
# delete keys or flush the whole database as a side effect of other operations.
# Specifically Redis deletes objects independently of a user call in the
# following scenarios:
#
# 1) On eviction, because of the maxmemory and maxmemory policy configurations,
#    in order to make room for new data, without going over the specified
#    memory limit.
# 2) Because of expire: when a key with an associated time to live (see the
#    EXPIRE command) must be deleted from memory.
# 3) Because of a side effect of a command that stores data on a key that may
#    already exist. For example the RENAME command may delete the old key
#    content when it is replaced with another one. Similarly SUNIONSTORE
#    or SORT with STORE option may delete existing keys. The SET command
#    itself removes any old content of the specified key in order to replace
#    it with the specified string.
# 4) During replication, when a replica performs a full resynchronization with
#    its master, the content of the whole database is removed in order to
#    load the RDB file just transferred.
#
# In all the above cases the default is to delete objects in a blocking way,
# like if DEL was called. However you can configure each case specifically
# in order to instead release memory in a non-blocking way like if UNLINK
# was called, using the following configuration directives:

lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no

############################## APPEND ONLY MODE ###############################

# By default Redis asynchronously dumps the dataset on disk. This mode is
# good enough in many applications, but an issue with the Redis process or
# a power outage may result into a few minutes of writes lost (depending on
# the configured save points).
#
# The Append Only File is an alternative persistence mode that provides
# much better durability. For instance using the default data fsync policy
# (see later in the config file) Redis can lose just one second of writes in a
# dramatic event like a server power outage, or a single write if something
# wrong with the Redis process itself happens, but the operating system is
# still running correctly.
#
# AOF and RDB persistence can be enabled at the same time without problems.
# If the AOF is enabled on startup Redis will load the AOF, that is the file
# with the better durability guarantees.
#
# Please check http://redis.io/topics/persistence for more information.

# 默认情况下，Redis是异步的把数据导出到磁盘上。这种模式在很多应用里已经足够好，但Redis进程
# 出问题或断电时可能造成一段时间的写操作丢失(这取决于配置的save指令)。
#
# AOF是一种提供了更可靠的替代持久化模式，例如使用默认的数据写入文件策略（参见后面的配置）
# 在遇到像服务器断电或单写情况下Redis自身进程出问题但操作系统仍正常运行等突发事件时，Redis
# 能只丢失1秒的写操作。
#
# AOF和RDB持久化能同时启动并且不会有问题。
# 如果AOF开启，那么在启动时Redis将加载AOF文件，它更能保证数据的可靠性。
appendonly no

# The name of the append only file (default: "appendonly.aof")
# aof文件名
appendfilename "appendonly_master_7001.aof"

# The fsync() call tells the Operating System to actually write data on disk
# instead of waiting for more data in the output buffer. Some OS will really flush
# data on disk, some other OS will just try to do it ASAP.
#
# Redis supports three different modes:
#
# no: don't fsync, just let the OS flush the data when it wants. Faster.
# always: fsync after every write to the append only log. Slow, Safest.
# everysec: fsync only one time every second. Compromise.
#
# The default is "everysec", as that's usually the right compromise between
# speed and data safety. It's up to you to understand if you can relax this to
# "no" that will let the operating system flush the output buffer when
# it wants, for better performances (but if you can live with the idea of
# some data loss consider the default persistence mode that's snapshotting),
# or on the contrary, use "always" that's very slow but a bit safer than
# everysec.
#
# More details please check the following article:
# http://antirez.com/post/redis-persistence-demystified.html
#
# If unsure, use "everysec".
# appendfsync always
# fsync() 系统调用告诉操作系统把数据写到磁盘上，而不是等更多的数据进入输出缓冲区。
# 有些操作系统会真的把数据马上刷到磁盘上；有些则会尽快去尝试这么做。
#
# Redis支持三种不同的模式：
#
# no：不要立刻刷，只有在操作系统需要刷的时候再刷。比较快。
# always：每次写操作都立刻写入到aof文件。慢，但是最安全。
# everysec：每秒写一次。折中方案。 
appendfsync everysec
# appendfsync no

# When the AOF fsync policy is set to always or everysec, and a background
# saving process (a background save or AOF log background rewriting) is
# performing a lot of I/O against the disk, in some Linux configurations
# Redis may block too long on the fsync() call. Note that there is no fix for
# this currently, as even performing fsync in a different thread will block
# our synchronous write(2) call.
#
# In order to mitigate this problem it's possible to use the following option
# that will prevent fsync() from being called in the main process while a
# BGSAVE or BGREWRITEAOF is in progress.
#
# This means that while another child is saving, the durability of Redis is
# the same as "appendfsync none". In practical terms, this means that it is
# possible to lose up to 30 seconds of log in the worst scenario (with the
# default Linux settings).
#
# If you have latency problems turn this to "yes". Otherwise leave it as
# "no" that is the safest pick from the point of view of durability.

# 如果AOF的同步策略设置成 "always" 或者 "everysec"，并且后台的存储进程（后台存储或写入AOF
# 日志）会产生很多磁盘I/O开销。某些Linux的配置下会使Redis因为 fsync()系统调用而阻塞很久。
# 注意，目前对这个情况还没有完美修正，甚至不同线程的 fsync() 会阻塞我们同步的write(2)调用。
#
# 为了缓解这个问题，可以用下面这个选项。它可以在 BGSAVE 或 BGREWRITEAOF 处理时阻止主进程进行fsync()。
# 
# 这就意味着如果有子进程在进行保存操作，那么Redis就处于"不可同步"的状态。
# 这实际上是说，在最差的情况下可能会丢掉30秒钟的日志数据。（默认Linux设定）
# 
# 如果你有延时问题把这个设置成"yes"，否则就保持"no"，这是保存持久数据的最安全的方式。
no-appendfsync-on-rewrite no

# Automatic rewrite of the append only file.
# Redis is able to automatically rewrite the log file implicitly calling
# BGREWRITEAOF when the AOF log size grows by the specified percentage.
#
# This is how it works: Redis remembers the size of the AOF file after the
# latest rewrite (if no rewrite has happened since the restart, the size of
# the AOF at startup is used).
#
# This base size is compared to the current size. If the current size is
# bigger than the specified percentage, the rewrite is triggered. Also
# you need to specify a minimal size for the AOF file to be rewritten, this
# is useful to avoid rewriting the AOF file even if the percentage increase
# is reached but it is still pretty small.
#
# Specify a percentage of zero in order to disable the automatic AOF
# rewrite feature.
# 自动重写AOF文件

auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb

# An AOF file may be found to be truncated at the end during the Redis
# startup process, when the AOF data gets loaded back into memory.
# This may happen when the system where Redis is running
# crashes, especially when an ext4 filesystem is mounted without the
# data=ordered option (however this can't happen when Redis itself
# crashes or aborts but the operating system still works correctly).
#
# Redis can either exit with an error when this happens, or load as much
# data as possible (the default now) and start if the AOF file is found
# to be truncated at the end. The following option controls this behavior.
#
# If aof-load-truncated is set to yes, a truncated AOF file is loaded and
# the Redis server starts emitting a log to inform the user of the event.
# Otherwise if the option is set to no, the server aborts with an error
# and refuses to start. When the option is set to no, the user requires
# to fix the AOF file using the "redis-check-aof" utility before to restart
# the server.
#
# Note that if the AOF file will be found to be corrupted in the middle
# the server will still exit with an error. This option only applies when
# Redis will try to read more data from the AOF file but not enough bytes
# will be found.
# AOF文件可能在尾部是不完整的（这跟system关闭有问题，尤其是mount ext4文件系统时
# 没有加上data=ordered选项。只会发生在os死时，redis自己死不会不完整）。
# 那redis重启时load进内存的时候就有问题了。
# 发生的时候，可以选择redis启动报错，并且通知用户和写日志，或者load尽量多正常的数据。
# 如果aof-load-truncated是yes，会自动发布一个log给客户端然后load（默认）。
# 如果是no，用户必须手动redis-check-aof修复AOF文件才可以。
# 注意，如果在读取的过程中，发现这个aof是损坏的，服务器也是会退出的，
# 这个选项仅仅用于当服务器尝试读取更多的数据但又找不到相应的数据时。
aof-load-truncated yes

# When rewriting the AOF file, Redis is able to use an RDB preamble in the
# AOF file for faster rewrites and recoveries. When this option is turned
# on the rewritten AOF file is composed of two different stanzas:
#
#   [RDB file][AOF tail]
#
# When loading Redis recognizes that the AOF file starts with the "REDIS"
# string and loads the prefixed RDB file, and continues loading the AOF
# tail.
aof-use-rdb-preamble yes

################################ LUA SCRIPTING  ###############################

# Max execution time of a Lua script in milliseconds.
#
# If the maximum execution time is reached Redis will log that a script is
# still in execution after the maximum allowed time and will start to
# reply to queries with an error.
#
# When a long running script exceeds the maximum execution time only the
# SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be
# used to stop a script that did not yet called write commands. The second
# is the only way to shut down the server in the case a write command was
# already issued by the script but the user doesn't want to wait for the natural
# termination of the script.
#
# Set it to 0 or a negative value for unlimited execution without warnings.
# Lua 脚本的最大执行时间，毫秒为单位
lua-time-limit 5000

################################ REDIS CLUSTER  ###############################

# Normal Redis instances can't be part of a Redis Cluster; only nodes that are
# started as cluster nodes can. In order to start a Redis instance as a
# cluster node enable the cluster support uncommenting the following:
#
# cluster-enabled yes

# Every cluster node has a cluster configuration file. This file is not
# intended to be edited by hand. It is created and updated by Redis nodes.
# Every Redis Cluster node requires a different cluster configuration file.
# Make sure that instances running in the same system do not have
# overlapping cluster configuration file names.
#
# cluster-config-file nodes-6379.conf

# Cluster node timeout is the amount of milliseconds a node must be unreachable
# for it to be considered in failure state.
# Most other internal time limits are multiple of the node timeout.
#
# cluster-node-timeout 15000

# A replica of a failing master will avoid to start a failover if its data
# looks too old.
#
# There is no simple way for a replica to actually have an exact measure of
# its "data age", so the following two checks are performed:
#
# 1) If there are multiple replicas able to failover, they exchange messages
#    in order to try to give an advantage to the replica with the best
#    replication offset (more data from the master processed).
#    Replicas will try to get their rank by offset, and apply to the start
#    of the failover a delay proportional to their rank.
#
# 2) Every single replica computes the time of the last interaction with
#    its master. This can be the last ping or command received (if the master
#    is still in the "connected" state), or the time that elapsed since the
#    disconnection with the master (if the replication link is currently down).
#    If the last interaction is too old, the replica will not try to failover
#    at all.
#
# The point "2" can be tuned by user. Specifically a replica will not perform
# the failover if, since the last interaction with the master, the time
# elapsed is greater than:
#
#   (node-timeout * replica-validity-factor) + repl-ping-replica-period
#
# So for example if node-timeout is 30 seconds, and the replica-validity-factor
# is 10, and assuming a default repl-ping-replica-period of 10 seconds, the
# replica will not try to failover if it was not able to talk with the master
# for longer than 310 seconds.
#
# A large replica-validity-factor may allow replicas with too old data to failover
# a master, while a too small value may prevent the cluster from being able to
# elect a replica at all.
#
# For maximum availability, it is possible to set the replica-validity-factor
# to a value of 0, which means, that replicas will always try to failover the
# master regardless of the last time they interacted with the master.
# (However they'll always try to apply a delay proportional to their
# offset rank).
#
# Zero is the only value able to guarantee that when all the partitions heal
# the cluster will always be able to continue.
#
# cluster-replica-validity-factor 10

# Cluster replicas are able to migrate to orphaned masters, that are masters
# that are left without working replicas. This improves the cluster ability
# to resist to failures as otherwise an orphaned master can't be failed over
# in case of failure if it has no working replicas.
#
# Replicas migrate to orphaned masters only if there are still at least a
# given number of other working replicas for their old master. This number
# is the "migration barrier". A migration barrier of 1 means that a replica
# will migrate only if there is at least 1 other working replica for its master
# and so forth. It usually reflects the number of replicas you want for every
# master in your cluster.
#
# Default is 1 (replicas migrate only if their masters remain with at least
# one replica). To disable migration just set it to a very large value.
# A value of 0 can be set but is useful only for debugging and dangerous
# in production.
#
# cluster-migration-barrier 1

# By default Redis Cluster nodes stop accepting queries if they detect there
# is at least an hash slot uncovered (no available node is serving it).
# This way if the cluster is partially down (for example a range of hash slots
# are no longer covered) all the cluster becomes, eventually, unavailable.
# It automatically returns available as soon as all the slots are covered again.
#
# However sometimes you want the subset of the cluster which is working,
# to continue to accept queries for the part of the key space that is still
# covered. In order to do so, just set the cluster-require-full-coverage
# option to no.
#
# cluster-require-full-coverage yes

# This option, when set to yes, prevents replicas from trying to failover its
# master during master failures. However the master can still perform a
# manual failover, if forced to do so.
#
# This is useful in different scenarios, especially in the case of multiple
# data center operations, where we want one side to never be promoted if not
# in the case of a total DC failure.
#
# cluster-replica-no-failover no

# In order to setup your cluster make sure to read the documentation
# available at http://redis.io web site.

########################## CLUSTER DOCKER/NAT support  ########################

# In certain deployments, Redis Cluster nodes address discovery fails, because
# addresses are NAT-ted or because ports are forwarded (the typical case is
# Docker and other containers).
#
# In order to make Redis Cluster working in such environments, a static
# configuration where each node knows its public address is needed. The
# following two options are used for this scope, and are:
#
# * cluster-announce-ip
# * cluster-announce-port
# * cluster-announce-bus-port
#
# Each instruct the node about its address, client port, and cluster message
# bus port. The information is then published in the header of the bus packets
# so that other nodes will be able to correctly map the address of the node
# publishing the information.
#
# If the above options are not used, the normal Redis Cluster auto-detection
# will be used instead.
#
# Note that when remapped, the bus port may not be at the fixed offset of
# clients port + 10000, so you can specify any port and bus-port depending
# on how they get remapped. If the bus-port is not set, a fixed offset of
# 10000 will be used as usually.
#
# Example:
#
# cluster-announce-ip 10.1.1.5
# cluster-announce-port 6379
# cluster-announce-bus-port 6380

################################## SLOW LOG ###################################

# The Redis Slow Log is a system to log queries that exceeded a specified
# execution time. The execution time does not include the I/O operations
# like talking with the client, sending the reply and so forth,
# but just the time needed to actually execute the command (this is the only
# stage of command execution where the thread is blocked and can not serve
# other requests in the meantime).
#
# You can configure the slow log with two parameters: one tells Redis
# what is the execution time, in microseconds, to exceed in order for the
# command to get logged, and the other parameter is the length of the
# slow log. When a new command is logged the oldest one is removed from the
# queue of logged commands.

# The following time is expressed in microseconds, so 1000000 is equivalent
# to one second. Note that a negative number disables the slow log, while
# a value of zero forces the logging of every command.
# Redis慢查询日志可以记录超过指定时间的查询
slowlog-log-slower-than 10000

# There is no limit to this length. Just be aware that it will consume memory.
# You can reclaim memory used by the slow log with SLOWLOG RESET.
# 这个长度没有限制。只是要主要会消耗内存。你可以通过 SLOWLOG RESET 来回收内存。
slowlog-max-len 128

################################ LATENCY MONITOR ##############################

# The Redis latency monitoring subsystem samples different operations
# at runtime in order to collect data related to possible sources of
# latency of a Redis instance.
#
# Via the LATENCY command this information is available to the user that can
# print graphs and obtain reports.
#
# The system only logs operations that were performed in a time equal or
# greater than the amount of milliseconds specified via the
# latency-monitor-threshold configuration directive. When its value is set
# to zero, the latency monitor is turned off.
#
# By default latency monitoring is disabled since it is mostly not needed
# if you don't have latency issues, and collecting data has a performance
# impact, that while very small, can be measured under big load. Latency
# monitoring can easily be enabled at runtime using the command
# "CONFIG SET latency-monitor-threshold " if needed.
# redis延时监控系统在运行时会采样一些操作，以便收集可能导致延时的数据根源。
# 通过 LATENCY命令 可以打印一些图样和获取一些报告，方便监控
# 这个系统仅仅记录那个执行时间大于或等于预定时间（毫秒）的操作, 
# 这个预定时间是通过latency-monitor-threshold配置来指定的，
# 当设置为0时，这个监控系统处于停止状态
latency-monitor-threshold 0

############################# EVENT NOTIFICATION ##############################

# Redis can notify Pub/Sub clients about events happening in the key space.
# This feature is documented at http://redis.io/topics/notifications
#
# For instance if keyspace events notification is enabled, and a client
# performs a DEL operation on key "foo" stored in the Database 0, two
# messages will be published via Pub/Sub:
#
# PUBLISH __keyspace@0__:foo del
# PUBLISH __keyevent@0__:del foo
#
# It is possible to select the events that Redis will notify among a set
# of classes. Every class is identified by a single character:
#
#  K     Keyspace events, published with __keyspace@__ prefix.
#  E     Keyevent events, published with __keyevent@__ prefix.
#  g     Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
#  $     String commands
#  l     List commands
#  s     Set commands
#  h     Hash commands
#  z     Sorted set commands
#  x     Expired events (events generated every time a key expires)
#  e     Evicted events (events generated when a key is evicted for maxmemory)
#  A     Alias for g$lshzxe, so that the "AKE" string means all the events.
#
#  The "notify-keyspace-events" takes as argument a string that is composed
#  of zero or multiple characters. The empty string means that notifications
#  are disabled.
#
#  Example: to enable list and generic events, from the point of view of the
#           event name, use:
#
#  notify-keyspace-events Elg
#
#  Example 2: to get the stream of the expired keys subscribing to channel
#             name __keyevent@0__:expired use:
#
#  notify-keyspace-events Ex
#
#  By default all notifications are disabled because most users don't need
#  this feature and the feature has some overhead. Note that if you don't
#  specify at least one of K or E, no events will be delivered.
# Redis能通知 Pub/Sub 客户端关于键空间发生的事件，默认关闭
notify-keyspace-events ""

############################### ADVANCED CONFIG ###############################

# Hashes are encoded using a memory efficient data structure when they have a
# small number of entries, and the biggest entry does not exceed a given
# threshold. These thresholds can be configured using the following directives.
# 当hash只有少量的entry时，并且最大的entry所占空间没有超过指定的限制时，会用一种节省内存的
# 数据结构来编码。可以通过下面的指令来设定限制
hash-max-ziplist-entries 512
hash-max-ziplist-value 64

# Lists are also encoded in a special way to save a lot of space.
# The number of entries allowed per internal list node can be specified
# as a fixed maximum size or a maximum number of elements.
# For a fixed maximum size, use -5 through -1, meaning:
# -5: max size: 64 Kb  <-- not recommended for normal workloads
# -4: max size: 32 Kb  <-- not recommended
# -3: max size: 16 Kb  <-- probably not recommended
# -2: max size: 8 Kb   <-- good
# -1: max size: 4 Kb   <-- good
# Positive numbers mean store up to _exactly_ that number of elements
# per list node.
# The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size),
# but if your use case is unique, adjust the settings as necessary.
# 与hash似，数据元素较少的list，可以用另一种方式来编码从而节省大量空间。
# 这种特殊的方式只有在符合下面限制时才可以用
list-max-ziplist-size -2

# Lists may also be compressed.
# Compress depth is the number of quicklist ziplist nodes from *each* side of
# the list to *exclude* from compression.  The head and tail of the list
# are always uncompressed for fast push/pop operations.  Settings are:
# 0: disable all list compression
# 1: depth 1 means "don't start compressing until after 1 node into the list,
#    going from either the head or tail"
#    So: [head]->node->node->...->node->[tail]
#    [head], [tail] will always be uncompressed; inner nodes will compress.
# 2: [head]->[next]->node->node->...->node->[prev]->[tail]
#    2 here means: don't compress head or head->next or tail->prev or tail,
#    but compress all nodes between them.
# 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail]
# etc.
list-compress-depth 0

# Sets have a special encoding in just one case: when a set is composed
# of just strings that happen to be integers in radix 10 in the range
# of 64 bit signed integers.
# The following configuration setting sets the limit in the size of the
# set in order to use this special memory saving encoding.
# set有一种特殊编码的情况：当set数据全是十进制64位有符号整型数字构成的字符串时。
# 下面这个配置项就是用来设置set使用这种编码来节省内存的最大长度。
set-max-intset-entries 512

# Similarly to hashes and lists, sorted sets are also specially encoded in
# order to save a lot of space. This encoding is only used when the length and
# elements of a sorted set are below the following limits:
# 与hash和list相似，有序集合也可以用一种特别的编码方式来节省大量空间。
# 这种编码只适合长度和元素都小于下面限制的有序集
zset-max-ziplist-entries 128
zset-max-ziplist-value 64

# HyperLogLog sparse representation bytes limit. The limit includes the
# 16 bytes header. When an HyperLogLog using the sparse representation crosses
# this limit, it is converted into the dense representation.
#
# A value greater than 16000 is totally useless, since at that point the
# dense representation is more memory efficient.
#
# The suggested value is ~ 3000 in order to have the benefits of
# the space efficient encoding without slowing down too much PFADD,
# which is O(N) with the sparse encoding. The value can be raised to
# ~ 10000 when CPU is not a concern, but space is, and the data set is
# composed of many HyperLogLogs with cardinality in the 0 - 15000 range.
# HyperLogLog稀疏结构表示字节的限制。该限制包括
# 16个字节的头。当HyperLogLog使用稀疏结构表示
# 这些限制，它会被转换成密度表示。
# 值大于16000是完全没用的，因为在该点
# 密集的表示是更多的内存效率。
# 建议值是3000左右，以便具有的内存好处, 减少内存的消耗
hll-sparse-max-bytes 3000

# Streams macro node max size / items. The stream data structure is a radix
# tree of big nodes that encode multiple items inside. Using this configuration
# it is possible to configure how big a single node can be in bytes, and the
# maximum number of items it may contain before switching to a new node when
# appending new stream entries. If any of the following settings are set to
# zero, the limit is ignored, so for instance it is possible to set just a
# max entires limit by setting max-bytes to 0 and max-entries to the desired
# value.
stream-node-max-bytes 4096
stream-node-max-entries 100

# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
# order to help rehashing the main Redis hash table (the one mapping top-level
# keys to values). The hash table implementation Redis uses (see dict.c)
# performs a lazy rehashing: the more operation you run into a hash table
# that is rehashing, the more rehashing "steps" are performed, so if the
# server is idle the rehashing is never complete and some more memory is used
# by the hash table.
#
# The default is to use this millisecond 10 times every second in order to
# actively rehash the main dictionaries, freeing memory when possible.
#
# If unsure:
# use "activerehashing no" if you have hard latency requirements and it is
# not a good thing in your environment that Redis can reply from time to time
# to queries with 2 milliseconds delay.
#
# use "activerehashing yes" if you don't have such hard requirements but
# want to free memory asap when possible.
# 启用哈希刷新，每100个CPU毫秒会拿出1个毫秒来刷新Redis的主哈希表（顶级键值映射表）
activerehashing yes

# The client output buffer limits can be used to force disconnection of clients
# that are not reading data from the server fast enough for some reason (a
# common reason is that a Pub/Sub client can't consume messages as fast as the
# publisher can produce them).
#
# The limit can be set differently for the three different classes of clients:
#
# normal -> normal clients including MONITOR clients
# replica  -> replica clients
# pubsub -> clients subscribed to at least one pubsub channel or pattern
#
# The syntax of every client-output-buffer-limit directive is the following:
#
# client-output-buffer-limit    
#
# A client is immediately disconnected once the hard limit is reached, or if
# the soft limit is reached and remains reached for the specified number of
# seconds (continuously).
# So for instance if the hard limit is 32 megabytes and the soft limit is
# 16 megabytes / 10 seconds, the client will get disconnected immediately
# if the size of the output buffers reach 32 megabytes, but will also get
# disconnected if the client reaches 16 megabytes and continuously overcomes
# the limit for 10 seconds.
#
# By default normal clients are not limited because they don't receive data
# without asking (in a push way), but just after a request, so only
# asynchronous clients may create a scenario where data is requested faster
# than it can read.
#
# Instead there is a default limit for pubsub and replica clients, since
# subscribers and replicas receive data in a push fashion.
#
# Both the hard or the soft limit can be disabled by setting them to zero.
# 客户端的输出缓冲区的限制，可用于强制断开那些因为某种原因从服务器读取数据的速度不够快的客户端
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60

# Client query buffers accumulate new commands. They are limited to a fixed
# amount by default in order to avoid that a protocol desynchronization (for
# instance due to a bug in the client) will lead to unbound memory usage in
# the query buffer. However you can configure it here if you have very special
# needs, such us huge multi/exec requests or alike.
#
# client-query-buffer-limit 1gb

# In the Redis protocol, bulk requests, that are, elements representing single
# strings, are normally limited ot 512 mb. However you can change this limit
# here.
#
# proto-max-bulk-len 512mb

# Redis calls an internal function to perform many background tasks, like
# closing connections of clients in timeout, purging expired keys that are
# never requested, and so forth.
#
# Not all tasks are performed with the same frequency, but Redis checks for
# tasks to perform according to the specified "hz" value.
#
# By default "hz" is set to 10. Raising the value will use more CPU when
# Redis is idle, but at the same time will make Redis more responsive when
# there are many keys expiring at the same time, and timeouts may be
# handled with more precision.
#
# The range is between 1 and 500, however a value over 100 is usually not
# a good idea. Most users should use the default of 10 and raise this up to
# 100 only in environments where very low latency is required.
# 默认情况下，“hz”的被设定为10。提高该值将在Redis空闲时使用更多的CPU时，但同时当有多个key
# 同时到期会使Redis的反应更灵敏，以及超时可以更精确地处理
hz 10

# Normally it is useful to have an HZ value which is proportional to the
# number of clients connected. This is useful in order, for instance, to
# avoid too many clients are processed for each background task invocation
# in order to avoid latency spikes.
#
# Since the default HZ value by default is conservatively set to 10, Redis
# offers, and enables by default, the ability to use an adaptive HZ value
# which will temporary raise when there are many connected clients.
#
# When dynamic HZ is enabled, the actual configured HZ will be used as
# as a baseline, but multiples of the configured HZ value will be actually
# used as needed once more clients are connected. In this way an idle
# instance will use very little CPU time while a busy instance will be
# more responsive.
dynamic-hz yes

# When a child rewrites the AOF file, if the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally and avoid
# big latency spikes.
# 当一个子进程重写AOF文件时，如果启用下面的选项，则文件每生成32M数据会被同步
aof-rewrite-incremental-fsync yes

# When redis saves RDB file, if the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally and avoid
# big latency spikes.
rdb-save-incremental-fsync yes

# Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good
# idea to start with the default settings and only change them after investigating
# how to improve the performances and how the keys LFU change over time, which
# is possible to inspect via the OBJECT FREQ command.
#
# There are two tunable parameters in the Redis LFU implementation: the
# counter logarithm factor and the counter decay time. It is important to
# understand what the two parameters mean before changing them.
#
# The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis
# uses a probabilistic increment with logarithmic behavior. Given the value
# of the old counter, when a key is accessed, the counter is incremented in
# this way:
#
# 1. A random number R between 0 and 1 is extracted.
# 2. A probability P is calculated as 1/(old_value*lfu_log_factor+1).
# 3. The counter is incremented only if R < P.
#
# The default lfu-log-factor is 10. This is a table of how the frequency
# counter changes with a different number of accesses with differend
# logarithmic factors:
#
# +--------+------------+------------+------------+------------+------------+
# | factor | 100 hits   | 1000 hits  | 100K hits  | 1M hits    | 10M hits   |
# +--------+------------+------------+------------+------------+------------+
# | 0      | 104        | 255        | 255        | 255        | 255        |
# +--------+------------+------------+------------+------------+------------+
# | 1      | 18         | 49         | 255        | 255        | 255        |
# +--------+------------+------------+------------+------------+------------+
# | 10     | 10         | 18         | 142        | 255        | 255        |
# +--------+------------+------------+------------+------------+------------+
# | 100    | 8          | 11         | 49         | 143        | 255        |
# +--------+------------+------------+------------+------------+------------+
#
# NOTE: The above table was obtained by running the following commands:
#
#   redis-benchmark -n 1000000 incr foo
#   redis-cli object freq foo
#
# NOTE 2: The counter initial value is 5 in order to give new objects a chance
# to accumulate hits.
#
# The counter decay time is the time, in minutes, that must elapse in order
# for the key counter to be divided by two (or decremented if it has a value
# less <= 10).
#
# The default value for the lfu-decay-time is 1. A Special value of 0 means to
# decay the counter every time it happens to be scanned.
#
# lfu-log-factor 10
# lfu-decay-time 1

########################### ACTIVE DEFRAGMENTATION #######################
#
# WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested
# even in production and manually tested by multiple engineers for some
# time.
#
# What is active defragmentation?
# -------------------------------
#
# Active (online) defragmentation allows a Redis server to compact the
# spaces left between small allocations and deallocations of data in memory,
# thus allowing to reclaim back memory.
#
# Fragmentation is a natural process that happens with every allocator (but
# less so with Jemalloc, fortunately) and certain workloads. Normally a server
# restart is needed in order to lower the fragmentation, or at least to flush
# away all the data and create it again. However thanks to this feature
# implemented by Oran Agra for Redis 4.0 this process can happen at runtime
# in an "hot" way, while the server is running.
#
# Basically when the fragmentation is over a certain level (see the
# configuration options below) Redis will start to create new copies of the
# values in contiguous memory regions by exploiting certain specific Jemalloc
# features (in order to understand if an allocation is causing fragmentation
# and to allocate it in a better place), and at the same time, will release the
# old copies of the data. This process, repeated incrementally for all the keys
# will cause the fragmentation to drop back to normal values.
#
# Important things to understand:
#
# 1. This feature is disabled by default, and only works if you compiled Redis
#    to use the copy of Jemalloc we ship with the source code of Redis.
#    This is the default with Linux builds.
#
# 2. You never need to enable this feature if you don't have fragmentation
#    issues.
#
# 3. Once you experience fragmentation, you can enable this feature when
#    needed with the command "CONFIG SET activedefrag yes".
#
# The configuration parameters are able to fine tune the behavior of the
# defragmentation process. If you are not sure about what they mean it is
# a good idea to leave the defaults untouched.

# Enabled active defragmentation
# activedefrag yes

# Minimum amount of fragmentation waste to start active defrag
# active-defrag-ignore-bytes 100mb

# Minimum percentage of fragmentation to start active defrag
# active-defrag-threshold-lower 10

# Maximum percentage of fragmentation at which we use maximum effort
# active-defrag-threshold-upper 100

# Minimal effort for defrag in CPU percentage
# active-defrag-cycle-min 5

# Maximal effort for defrag in CPU percentage
# active-defrag-cycle-max 75

# Maximum number of set/hash/zset/list fields that will be processed from
# the main dictionary scan
# active-defrag-max-scan-fields 1000

sentinel_7001.conf样例（我的多个故障转移通知）：

# Example sentinel.conf

# *** IMPORTANT ***
#
# By default Sentinel will not be reachable from interfaces different than
# localhost, either use the 'bind' directive to bind to a list of network
# interfaces, or disable protected mode with "protected-mode no" by
# adding it to this configuration file.
#
# Before doing that MAKE SURE the instance is protected from the outside
# world via firewalling or other means.
#
# For example you may use one of the following:
#
# bind 127.0.0.1 192.168.1.1
#
# protected-mode no

# port 
# The port that this sentinel instance will run on
#port 26379
port 7101

# By default Redis Sentinel does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis-sentinel.pid when
# daemonized.
#daemonize no
daemonize yes

# When running daemonized, Redis Sentinel writes a pid file in
# /var/run/redis-sentinel.pid by default. You can specify a custom pid file
# location here.
pidfile "/var/run/redis-sentinel_7101.pid"

# Specify the log file name. Also the empty string can be used to force
# Sentinel to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile "/var/log/redis/sentinel_7101.log"

# sentinel announce-ip 
# sentinel announce-port 
#
# The above two configuration directives are useful in environments where,
# because of NAT, Sentinel is reachable from outside via a non-local address.
#
# When announce-ip is provided, the Sentinel will claim the specified IP address
# in HELLO messages used to gossip its presence, instead of auto-detecting the
# local address as it usually does.
#
# Similarly when announce-port is provided and is valid and non-zero, Sentinel
# will announce the specified TCP port.
#
# The two options don't need to be used together, if only announce-ip is
# provided, the Sentinel will announce the specified IP and the server port
# as specified by the "port" option. If only announce-port is provided, the
# Sentinel will announce the auto-detected local IP and the specified port.
#
# Example:
#
# sentinel announce-ip 1.2.3.4

# dir 
# Every long running process should have a well-defined working directory.
# For Redis Sentinel to chdir to /tmp at startup is the simplest thing
# for the process to don't interfere with administrative tasks such as
# unmounting filesystems.
dir "/tmp"

# sentinel monitor    
#
# Tells Sentinel to monitor this master, and to consider it in O_DOWN
# (Objectively Down) state only if at least  sentinels agree.
#
# Note that whatever is the ODOWN quorum, a Sentinel will require to
# be elected by the majority of the known Sentinels in order to
# start a failover, so no failover can be performed in minority.
#
# Replicas are auto-discovered, so you don't need to specify replicas in
# any way. Sentinel itself will rewrite this configuration file adding
# the replicas using additional configuration options.
# Also note that the configuration file is rewritten when a
# replica is promoted to master.
#
# Note: master name should not include special characters or spaces.
# The valid charset is A-z 0-9 and the three characters ".-_".
# 哨兵监控这个master，在至少quorum个哨兵实例都认为master down后把master标记为odown
# （objective down客观down；相对应的存在sdown，subjective down，主观down）状态。
# slaves是自动发现，所以你没必要明确指定slaves。
#sentinel monitor mymaster 127.0.0.1 6379 2
sentinel myid a00a954cb39f50b22e068df4298d63c2b6baa084

# 设置master slavers验证密码(要想使用哨兵模式检查，只能将主、从节点的验证密码设置成一样的，至于是复制的验证还是读写的验证尚不清楚)
sentinel deny-scripts-reconfig yes
# sentinel auth-pass  
#
# Set the password to use to authenticate with the master and replicas.
# Useful if there is a password set in the Redis instances to monitor.
#
# Note that the master password is also used for replicas, so it is not
# possible to set a different password in masters and replicas instances
# if you want to be able to monitor these instances with Sentinel.
#
# However you can have Redis instances without the authentication enabled
# mixed with Redis instances requiring the authentication (as long as the
# password set is the same for all the instances requiring the password) as
# the AUTH command will have no effect in Redis instances with authentication
# switched off.
#
# Example:
#
# sentinel auth-pass mymaster MySUPER--secret-0123passw0rd

# sentinel down-after-milliseconds  
#
# Number of milliseconds the master (or any attached replica or sentinel) should
# be unreachable (as in, not acceptable reply to PING, continuously, for the
# specified period) in order to consider it in S_DOWN state (Subjectively
# Down).
#
# Default is 30 seconds.
# master或slave多长时间（默认30秒）不能使用后标记为s_down状态。
#sentinel down-after-milliseconds mymaster 30000
sentinel monitor mymaster 127.0.0.1 7001 1

# sentinel parallel-syncs  
#
# How many replicas we can reconfigure to point to the new replica simultaneously
# during the failover. Use a low number if you use the replicas to serve query
# to avoid that all the replicas will be unreachable at about the same
# time while performing the synchronization with the master.
sentinel down-after-milliseconds mymaster 15000

# sentinel failover-timeout  
#
# Specifies the failover timeout in milliseconds. It is used in many ways:
#
# - The time needed to re-start a failover after a previous failover was
#   already tried against the same master by a given Sentinel, is two
#   times the failover timeout.
#
# - The time needed for a replica replicating to a wrong master according
#   to a Sentinel current configuration, to be forced to replicate
#   with the right master, is exactly the failover timeout (counting since
#   the moment a Sentinel detected the misconfiguration).
#
# - The time needed to cancel a failover that is already in progress but
#   did not produced any configuration change (SLAVEOF NO ONE yet not
#   acknowledged by the promoted replica).
#
# - The maximum time a failover in progress waits for all the replicas to be
#   reconfigured as replicas of the new master. However even after this time
#   the replicas will be reconfigured by the Sentinels anyway, but not with
#   the exact parallel-syncs progression as specified.
#
# Default is 3 minutes.
# 若sentinel在该配置值内未能完成failover操作（即故障时master/slave自动切换），则认为本次failover失败
sentinel notification-script mymaster /var/redis/sentnel_notify.sh

# SCRIPTS EXECUTION
#
# sentinel notification-script and sentinel reconfig-script are used in order
# to configure scripts that are called to notify the system administrator
# or to reconfigure clients after a failover. The scripts are executed
# with the following rules for error handling:
#
# If script exits with "1" the execution is retried later (up to a maximum
# number of times currently set to 10).
#
# If script exits with "2" (or an higher value) the script execution is
# not retried.
#
# If script terminates because it receives a signal the behavior is the same
# as exit code 1.
#
# A script has a maximum running time of 60 seconds. After this limit is
# reached the script is terminated with a SIGKILL and the execution retried.

# NOTIFICATION SCRIPT
#
# sentinel notification-script  
#
# Call the specified notification script for any sentinel event that is
# generated in the WARNING level (for instance -sdown, -odown, and so forth).
# This script should notify the system administrator via email, SMS, or any
# other messaging system, that there is something wrong with the monitored
# Redis systems.
#
# The script is called with just two arguments: the first is the event type
# and the second the event description.
#
# The script must exist and be executable in order for sentinel to start if
# this option is provided.
#
# Example:
#
# 哨兵监控master，在故障转移多次(10次)尝试后失败就弃用用户写好的脚本告警(
sentinel auth-pass mymaster [email protected]

# CLIENTS RECONFIGURATION SCRIPT
#
# 客户端的告警脚本启用
# sentinel client-reconfig-script  
#
# When the master changed because of a failover a script can be called in
# order to perform application-specific tasks to notify the clients that the
# configuration has changed and the master is at a different address.
#
# The following arguments are passed to the script:
#
#       
#
#  is currently always "failover"
#  is either "leader" or "observer"
#
# The arguments from-ip, from-port, to-ip, to-port are used to communicate
# the old address of the master and the new address of the elected replica
# (now a master).
#
# This script should be resistant to multiple invocations.
#
# Example:
#
# sentinel client-reconfig-script mymaster /var/redis/reconfig.sh

# SECURITY
#
# By default SENTINEL SET will not be able to change the notification-script
# and client-reconfig-script at runtime. This avoids a trivial security issue
# where clients can set the script to anything and trigger a failover in order
# to get the program executed.

sentinel config-epoch mymaster 2

# REDIS COMMANDS RENAMING
#
# Sometimes the Redis server has certain commands, that are needed for Sentinel
# to work correctly, renamed to unguessable strings. This is often the case
# of CONFIG and SLAVEOF in the context of providers that provide Redis as
# a service, and don't want the customers to reconfigure the instances outside
# of the administration console.
#
# In such case it is possible to tell Sentinel to use different command names
# instead of the normal ones. For example if the master "mymaster", and the
# associated replicas, have "CONFIG" all renamed to "GUESSME", I could use:
#
# SENTINEL rename-command mymaster CONFIG GUESSME
#
# After such configuration is set, every time Sentinel would use CONFIG it will
# use GUESSME instead. Note that there is no actual need to respect the command
# case, so writing "config guessme" is the same in the example above.
#
# SENTINEL SET can also be used in order to perform this configuration at runtime.
#
# In order to set a command back to its original name (undo the renaming), it
# is possible to just rename a command to itsef:
#
# SENTINEL rename-command mymaster CONFIG CONFIG

#这个好像原始配置没有啊，指故障转移时最多可以有多个个从节点同时对新柱节点进行数据同步
sentinel leader-epoch mymaster 5
sentinel known-replica mymaster 127.0.0.1 7002

# Generated by CONFIG REWRITE
protected-mode no
sentinel known-replica mymaster 127.0.0.1 7003
sentinel known-sentinel mymaster 127.0.0.1 7102 79414accf7161cbaf275b733b68e447e2ba80a84
sentinel known-sentinel mymaster 127.0.0.1 7103 b4b9bb3729cd6ec1ccd144ac04ee8c62ee78be9b
sentinel current-epoch 5

4. 写好启停脚本、故障转移本地通知脚本

启停脚本：

#!/bin/bash
#这个主要是1主两从，然后三个哨兵监控启动脚本

#先kill存在的，
ps -ef|grep redis-sentinel|grep -v grep|awk '{print $2}'|while read line;do kill -9 $line;done
ps -ef|grep redis-server|grep -v grep|awk '{print $2}'|while read line;do kill -9 $line;done

#再启动master
cd /opt/redis-5.0.10/conf/redis_master
redis-server /opt/redis-5.0.10/conf/redis_master/redis_master_7001.conf &

#再启动slave
cd /opt/redis-5.0.10/conf/redis_slave
redis-server /opt/redis-5.0.10/conf/redis_slave/redis_slave_7002.conf &
redis-server /opt/redis-5.0.10/conf/redis_slave/redis_slave_7003.conf &

#再启动哨兵
cd /opt/redis-5.0.10/conf/redis_master
redis-sentinel sentinel_7101.conf &
redis-sentinel sentinel_7102.conf &
redis-sentinel sentinel_7103.conf &

本地通知脚本(简单的记录)：

#!/bin/bash
#传递进来的参数除了第一个是当前shell脚本的文件名外
#剩下的就是        
params="$1 $2 $3 $4 $5 $6 $7 "
datestr=`date +"%Y-%m-%d %H:%M:%S"`
tipstr="哨兵检测到redis集群故障转移:"
echo "${datestr} ${tipstr}${params}" >> /var/log/redis/sentinel_notify_sh.txt

5.测试主从复制、故障转移、数据恢复

在Linux中用：redis-cli -h ip -p port -a password 命令启动客户端

5.1 测试主从复制

①启动主客户端，写入数据

②启动从客户端cli，能读取主节点数据，但默认不能写入数据

5.2 测试故障转移

①kill master进程

②启动各个从客户端cli，查看当前节点主从状态

主节点挂掉了

7002的从节点变成了主节点

7003的从节点还是从节点，指向主节点是7002的

是replica-priority 数字较小的7002端口的从节点升为了master节点

再kill 7002这个新master的进程

7003变成新的master，0个slave连接它

 

再启动7001的server和7002的server

7003 还是主节点，

写入数据

从节点还是能得到这些数据

下线，当前7003的master

7002升级为master

为什么？因为默认之前7001的replica-propro是100，优先级低

5.3 测试 数据恢复

现在是7002为master，7001和7003为slave，当kill所有server时，在启动，按原来应该是7001为master，看结果到底是不是：

发现依然还是7002最后的状态下谁是master就是master，为什么？

可以看到进程pid也已经变了，保留了最后的状态，因为sentinel哨兵都没有挂，而且一瞬间server都挂了，来不及选后挂的为master

 

测试数据都还在。

再来测试，把server、sentinel全都一起挂掉，再重启

进程pid都变化了，依然还是7002是master，说明持久化过程中，会有将最后状态的master slave信息持久化在文件里，就算全部所有都挂掉了，还是能记住那个是主节点。

 

那么现在，测试，全部挂掉，不起之前记录的7002主节点，只启用7003测试：

只起7003这个slave，发现不能变成主节点，那么如果，这时候启动sentinel呢？因为不管是日志记录7002master，还是sentinel初始启动的配置记录都是7001的master进行监听，大概率还是不能与7003通信？

但是要测试，因为可能之前就有记录7003是个slave，如果

只启动一个哨兵

7003依然还是slave，可能因为之前配置的默认2个及以上节点认为master挂了才算选新主，

再启动一个新的sentinel测试

7003依然还是slave

再启动第三个 sentinel：

发现7003这个唯一的server依然还是slave

继续测试，启动之前结束状态时认为的7001是slave的server节点，该7001配置在sentinel里面是默认监听的节点，看是否能够通信重选master节点：

结果显示：7001也是结束状态之前的样子，slave，而且也不会触发重选主节点，7003也是slave

现在情况很明朗了，sentinel挂之前记住的是什么状态，后续再启动就是去跟之前记录的master通信，没通信到，也无法与slave通信，无法来主持重选master的工作；

slave数据也是根据本地持久化而来，还没找到新的master，数据只能读，无法写。

最后启动 7002 整体全挂之前的master：

挂掉前的master节点启动后，才会有新的master

查看故障转移本地通知脚本写入的log：

日志基本都是重选主，没选出来

那么开始挂掉当前7002的master再看日志：

刚才kill错了，kill了redis-sentinel 7102的了

再查看日志，发现日志没变化，而查看redis-cli中 已经发生故障转移了，将优先级更高的7003选为master了，就算只有两个sentinel的情况下刚好满足选主条件。

发现日志记录日期和时间不对，可能就是我的sentinel中配置些的通知本地的sh脚本有问题了。

打开发现，原来来csnd写文档，copy不小心末尾追加，弄多了，删除之，重启sentinel，想起来要故障迁移才会除非调用本地脚本来通知

先顺便测试 7001 slave，7003是master状态下，再杀掉7103的sentinel 只留一个sentinel，后再kill 7003的服务(把起来的7102的sentinel也杀掉)，看是否能够选主：

结果，只留一个sentinel选不了主了，说明跟设置中的两个以上认为master挂了的才能选主，指的是sentinel这个监控进程，而不是slave的个数，当然也可能是因为slave去掉了之后，只能下一个slave了，也只有1个不满足条件。

但是前面已经测试过，3个sentinel监控，1master 1slave，最后mster挂了，就留一个独苗的slave升级master，说明是用sentinel这个报告来决定的，否则slave只有一个了，怎么也满足不了2啊，到是能满足1。

而且官方的流程，也是sentinel发现主节点挂了，通知其它sentinel并发起投票先投自己来主持故障转移，超过半数以上，就是那个主持，现在是1个sentinel的情况下，1master 1slave，然后挂掉master，故障转移不了。一个可能是因为1不大于1，也可能因为文件中设置的数量为2导致的，需要去修改，然后重新测试

-------------------------------------------------------------------（咋先不管那个本地通知了，理解时sentinel的数量投票还是slave的数量影响故障转移重要多了）

 

sentinel投票影响大测试(sentinel monitor中默认2个数的限制，指的是sentinel个数)：

先恢复7001为mster：（启动脚本，全启动，7003为master，然后kill 7003 然后kill 7002，当7001为master了，再所有kill）

再所有server sentinel kill

修改sentinel中的 验证数量 为4个：

再按脚本启动，master1个， 5个 slave， 3个sentinel：

    修改脚本，发现sentinel会自动修改里面部分内容，搞得都错位了 sentinel monitor 中指明数量：

启动后，验证7001是master，然后kill 7001，5个slave中选举一个master看能否选成，如果选成，说明是对slave的数量，如果没宣称，说明是对sentinel数量的设置要求：

【结果】最终没有去选master出来，依然还是5个slave留在系统里，说明，这里sentinel monitor中 验证的数量说的就是sentinel的数量

 

测试只启1个sentinel且，监控从默认2个修改为1个 quorum

然后挂主节点，发现，保留的5个slave，头都是痛的，好像因为有地方设置的180秒内不能重新选为主节点，我的天，搞死人，而且还有bind的问题，最后就是不要bind这样外网都容易畅通的访问，危险性也会比较大，如果设置bind，麻烦也比较多，对应的sentinel也要设置bind

反正就是不要用一个sentinel去搞事情，至少3个，然后默认quorum 2个，恩姆，就这样了，搞死我了，他妈的谢个屁的文章，浪费老子元旦半天时间，草。

--------------------------------------------总结：--------------------------------------

①redis用端口配置多个实例，不建议用redis下的多个数据库形式，命名好key的规则就行，也就都是用:进行分隔

②redis配置主从结构，主外部主要写入，从默认只读(但主从复制可写)，为了网络io复制和master的写压力，最好一主两从，然后每个从下面又是两个从，这样子就比较好。

③master有性能压力，可以关闭持久化，让从来持久化就行，但是要做好措施，当集群或mater挂的时候，再启动，如果还是该mater为主节点，因为是清空的状态，从节点会跟着同步状态为情况导致数据丢失，要小心

④但测试结果表明，用哨兵模式之后，会保存集群最后选主的情况，集群重启时不管先后顺序都是等这个master起来，可能能缓解③中情况，但还是要信息。

⑤如果master起不来了，可以手动选着一个slave of 让其在一段时间后自动称为主节点，也可以，其它slave 再slaveof 指定这个节点，运行状态中手动配置

⑥使用哨兵模式，至少三台，默认的quorum 2个指的是至少2个哨兵认为master挂了，就开始选主，哨兵这个守护监控进程挂了，或者bind与 redis-server的配置不对应，也会无法进行有效投票选主，即使活着的哨兵个数大于quorum。

⑦可以在哨兵的日志里查看选主的情况，有没有选成功，那个哨兵没有进行有效的投票