Mycat 主从切换（mysql）
centos7
mysql5.7
服务器信息如下（实验环境，关闭机器的iptables防火墙和selinux）：
服务器主机名 ip 说明
Mycat-node 10.0.1.43 mycat服务器，
Mysql-node1 10.0.1.44 物理数据库Master数据库
Mysql-node2 10.0.1.44 物理数据库Slave数据库
三台机器分布修改主机名，并做hosts绑定
vim /etc/hosts
10.0.1.43 Mycat-node
10.0.1.44 Mysql-node1
10.0.1.45 Mysql-node2
Mysql主从复制（两个节点的mysql登录用户名和密码都是root/123456）
首先是Mysql-node1主节点配置操作
[root@Mysql-node1 ~]# cp /etc/my.cnf /etc/my.cnf.back
[root@Mysql-node1 ~]# vim /etc/my.cnf
[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
server-id=1
log-bin=mysql-bin
binlog-ignore-db = mysql,information_schema
sync_binlog = 1
binlog_checksum = none
binlog_format = mixed
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
:wq
[root@Mysql-node1 ~]# systemctl restart mysqld
登录mysql，授予slave从机复制权限
[root@Mysql-node1 ~]# mysql -uroot -p'123456'
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_length=1;
Query OK, 0 rows affected (0.00 sec)
mysql> grant replication slave,replication client on *.* to slave@'10.0.1.45' identified by "slave@123";
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> FLUSH TABLES WITH READ LOCK;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+--------------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+--------------------------+-------------------+
| mysql-bin.000001 | 734 | | mysql,information_schema | |
+------------------+----------+--------------+--------------------------+-------------------+
1 row in set (0.00 sec)
接着是slave从节点操作
[root@Mysql-node2 ~]# cp /etc/my.cnf /etc/my.cnf.back
[root@Mysql-node2 ~]# vim /etc/my.cnf
1 # For advice on how to change settings please see
2 # http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
3
4 [mysqld]
5 #
6 # Remove leading # and set to the amount of RAM for the most important data
7 # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
8 # innodb_buffer_pool_size = 128M
9 #
10 # Remove leading # to turn on a very important data integrity option: logging
11 # changes to the binary log between backups.
12 # log_bin
13 #
14 # Remove leading # to set options mainly useful for reporting servers.
15 # The server defaults are faster for transactions and fast SELECTs.
16 # Adjust sizes as needed, experiment to find the optimal values.
17 # join_buffer_size = 128M
18 # sort_buffer_size = 2M
19 # read_rnd_buffer_size = 2M
20 datadir=/var/lib/mysql
21 socket=/var/lib/mysql/mysql.sock
22
23 # Disabling symbolic-links is recommended to prevent assorted security risks
24 symbolic-links=0
25
26 server-id=2
27 log-bin=mysql-bin
28 replicate-ignore-db=mysql
29 slave-skip-errors = all
30
31
32
33 log-error=/var/log/mysqld.log
34 pid-file=/var/run/mysqld/mysqld.pid
:wq
[root@Mysql-node2 ~]# systemctl restart mysqld
登录slave节点的mysql，进行主从同步设置
[root@Mysql-node2 ~]# mysql -uroot -p'123456'
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> change master to master_host='10.0.1.44', \
-> master_user='slave', \
-> master_password='slave@123', \
-> master_log_file='mysql-bin.000001', \
-> master_log_pos=734;
Query OK, 0 rows affected, 2 warnings (0.30 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status \G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.0.1.44
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 734
Relay_Log_File: Mysql-node2-relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes #状态为YES主从复制环境已经OK ，不是YES要找原因
Slave_SQL_Running: Yes #状态为YES主从复制环境已经OK
Replicate_Do_DB:
Replicate_Ignore_DB: mysql
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 734
Relay_Log_Space: 533
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: d04f522b-6c79-11e9-bf10-000c2970f7f9
Master_Info_File: /var/lib/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
ERROR:
No query specified
在Mysql-node1主节点上操作
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)
在Mysql-node1上创建数据库
Mycat中间件安装、配置和测试（Mycat-node节点机器上操作）
Mycat安装
mkdir /test
cd /test
[root@Mycat-node test]# wget http://dl.mycat.io/1.6.6.1/Mycat-server-1.6.6.1-release-20181031195535-linux.tar.gz
[root@Mycat-node test]# tar zxf Mycat-server-1.6.6.1-release-20181031195535-linux.tar.gz
[root@Mycat-node test]# ll
total 198460
-rw-r--r-- 1 root root 185646832 May 2 09:12 jdk-8u181-linux-x64.tar.gz
drwxr-xr-x 7 root root 85 May 7 21:19 mycat
-rw-r--r-- 1 root root 17544969 Nov 7 12:25 Mycat-server-1.6.6.1-release-20181031195535-linux.tar.gz
-rw-r--r-- 1 root root 25680 Apr 27 2017 mysql57-community-release-el7-11.noarch.rpm
[root@Mycat-node test]# mv mycat/ /usr/local/
[root@Mycat-node test]# cd /usr/local/
[root@Mycat-node local]# ll
total 0
drwxr-xr-x. 2 root root 6 Apr 11 2018 bin
drwxr-xr-x. 2 root root 6 Apr 11 2018 etc
drwxr-xr-x. 2 root root 6 Apr 11 2018 games
drwxr-xr-x. 2 root root 6 Apr 11 2018 include
drwxr-xr-x 3 root root 26 May 2 09:20 jdk
drwxr-xr-x. 2 root root 6 Apr 11 2018 lib
drwxr-xr-x. 2 root root 6 Apr 11 2018 lib64
drwxr-xr-x. 2 root root 6 Apr 11 2018 libexec
drwxr-xr-x 7 root root 85 May 7 21:19 mycat
drwxr-xr-x. 2 root root 6 Apr 11 2018 sbin
drwxr-xr-x. 5 root root 49 Apr 29 00:05 share
drwxr-xr-x. 2 root root 6 Apr 11 2018 src
[root@Mycat-node local]# chmod 755 -R mycat/
[root@Mycat-node local]# ll
total 0
drwxr-xr-x. 2 root root 6 Apr 11 2018 bin
drwxr-xr-x. 2 root root 6 Apr 11 2018 etc
drwxr-xr-x. 2 root root 6 Apr 11 2018 games
drwxr-xr-x. 2 root root 6 Apr 11 2018 include
drwxr-xr-x 3 root root 26 May 2 09:20 jdk
drwxr-xr-x. 2 root root 6 Apr 11 2018 lib
drwxr-xr-x. 2 root root 6 Apr 11 2018 lib64
drwxr-xr-x. 2 root root 6 Apr 11 2018 libexec
drwxr-xr-x 7 root root 85 May 7 21:19 mycat
drwxr-xr-x. 2 root root 6 Apr 11 2018 sbin
drwxr-xr-x. 5 root root 49 Apr 29 00:05 share
drwxr-xr-x. 2 root root 6 Apr 11 2018 src
Mycat相关配置
[root@Mycat-node conf]# cd /usr/local/mycat/conf
[root@Mycat-node conf]# ll
total 104
-rwxr-xr-x 1 root root 88 Oct 31 2018 autopartition-long.txt
-rwxr-xr-x 1 root root 48 Oct 31 2018 auto-sharding-long.txt
-rwxr-xr-x 1 root root 62 Oct 31 2018 auto-sharding-rang-mod.txt
-rwxr-xr-x 1 root root 334 Oct 31 2018 cacheservice.properties
-rwxr-xr-x 1 root root 3244 Oct 31 2018 dbseq.sql
-rwxr-xr-x 1 root root 439 Oct 31 2018 ehcache.xml
-rwxr-xr-x 1 root root 2132 Oct 31 2018 index_to_charset.properties
-rwxr-xr-x 1 root root 1253 Oct 31 2018 log4j2.xml
-rwxr-xr-x 1 root root 178 Oct 31 2018 migrateTables.properties
-rwxr-xr-x 1 root root 262 Oct 31 2018 myid.properties
-rwxr-xr-x 1 root root 15 Oct 31 2018 partition-hash-int.txt
-rwxr-xr-x 1 root root 102 Oct 31 2018 partition-range-mod.txt
-rwxr-xr-x 1 root root 4678 Oct 31 2018 rule.xml
-rwxr-xr-x 1 root root 4219 Oct 31 2018 schema.xml
-rwxr-xr-x 1 root root 413 Oct 31 2018 sequence_conf.properties
-rwxr-xr-x 1 root root 75 Oct 31 2018 sequence_db_conf.properties
-rwxr-xr-x 1 root root 27 Oct 31 2018 sequence_distributed_conf.properties
-rwxr-xr-x 1 root root 51 Oct 31 2018 sequence_time_conf.properties
-rwxr-xr-x 1 root root 4851 Oct 31 2018 server.xml
-rwxr-xr-x 1 root root 16 Oct 31 2018 sharding-by-enum.txt
-rwxr-xr-x 1 root root 4299 Oct 31 2018 wrapper.conf
drwxr-xr-x 2 root root 4096 May 7 21:19 zkconf
drwxr-xr-x 2 root root 36 May 7 21:19 zkdownload
[root@Mycat-node conf]# cp server.xml server.xml.back
[root@Mycat-node conf]# cp schema.xml schema.xml.back
[root@Mycat-node conf]# vim server.xml
<user name="galaxis" defaultAccount="true">
<property name="password">123456</property>
<property name="schemas">mycat</property>
<!-- 表级 DML 权限设置 -->
<!--
<privileges check="false">
<schema name="TESTDB" dml="0110" >
<table name="tb01" dml="0000"></table>
<table name="tb02" dml="1111"></table>
</schema>
</privileges>
-->
</user>
<!-- #由于这里只定义了一个标签，所以把多余的都注释了.
<user name="user">
<property name="password">user</property>
<property name="schemas">TESTDB</property>
<property name="readOnly">true</property>
</user>
-->
实现主从自动切换的schema.xml配置：MySQL写节点宕机后自动切换到备用节点（也就是把从机也配置成writeHosts）：
[root@Mycat-node conf]# vim schema.xml
show slave status
[root@Mycat-node conf]# cd ../bin/
[root@Mycat-node bin]# ll
total 384
-rwxr-xr-x 1 root root 3567 Oct 31 2018 dataMigrate.sh
-rwxr-xr-x 1 root root 1225 Oct 31 2018 init_zk_data.sh
-rwxr-xr-x 1 root root 15714 Oct 31 2018 mycat
-rwxr-xr-x 1 root root 2941 Oct 31 2018 rehash.sh
-rwxr-xr-x 1 root root 2496 Oct 31 2018 startup_nowrap.sh
-rwxr-xr-x 1 root root 140198 Oct 31 2018 wrapper-linux-ppc-64
-rwxr-xr-x 1 root root 99401 Oct 31 2018 wrapper-linux-x86-32
-rwxr-xr-x 1 root root 111027 Oct 31 2018 wrapper-linux-x86-64
[root@Mycat-node bin]# ./mycat start
Starting Mycat-server...
[root@Mycat-node bin]# ./mycat status
Mycat-server is running (7700).
参考：https://www.cnblogs.com/kevingrace/p/9365840.html