整个MHA+keepalived+lvs+mysql高可用架构配置说明

整个MHA+keepalived+lvs+mysql高可用架构配置说明
1.1. 环境简介
1.1.1、vmvare虚拟机，系统版本CentOS7.5 x86_64位最小化安装，mysql的版本5.7.21，
1.1.2、虚拟机器的ssh端口均为默认22,
1.1.3、虚拟机的iptables全部关闭，
1.1.4、虚拟机的selinux全部关闭，
1.1.5、虚拟机服务器时间全部一致 ntpdate 0.asia.pool.ntp.org
1.1.6、3台机器的ssh端口为22**
1.2、此次试验采用的是3台机器，机器具体部署如下：
角色 IP地址（内网） 主机名称 节点机器部署服务 业务用途
Monitor 192.168.52.250 db250 mha4mysql-manager-0.58-0.el6
Master 192.168.52.251 db251 mha4mysql-node-0.58-0.el6 写入(keepalived)

slave(备master) 192.168.52.252 db252 mha4mysql-node-0.58-0.el6 keepalived
Slave 192.168.52.253 db253 mha4mysql-node-0.58-0.el6
读+备份数据
Lvs01 192.168.52.248 lvs248 lvs+keepalived
从库负载均衡
Lvs02 192.168.52.249 lvs249 lvs+keepavlied
从库负载均衡
Mysql write vip： 192.168.52.199
Mysql read vip： 192.168.52.159
1.3 系统架构图：

故障后架构图

1.4 架构实现原理：
1． 读操作
1 ） LVS 实现读操作的负载均衡；
2） Keepalived 在上层管理 LVS， 并对两台从库进行健康检测（通过定义 Ch
eck 脚本） ；
3） 一台从库出现故障后， Keepalived 将其剔除出负载均衡集群；

2. 写操作
   1 ） 在 Master 上绑定写 VIP（MHA 启动后会通过脚本进行操作）；
   2） MHA 监控 Master 状态，当 Master 出现故障后（宕机、复制暂停）时;
   3） 通过 Failover 脚本，卸载 Master 上的 WVIP；
   4） 通过 Failover 脚本在 Backup Master 上绑定 WVIP，提升其为主库；
   5） 同步并应用差异日志， 并将从库指向新主库；
   问题：当 MHA 把 Master 切换到了 Backup Master 上后， LVS 如何处理分发在 Ba
   ckup Master 上的读操作？
   解释： 由于 Keepalived 会通过脚本定期监控 Backup Master 的状态， 包括同步、
   SQL 线程、 I/O 线程， 所以当 Backup Master 升级为主库后， 这些状态都将消失，
   Keepalived 将自动将 Backup Master 剔除出负载均衡集群。
   1.5 说明介绍：
   Db252和db253是db251的slave从库，复制环境搭建后面会简单演示,其中master对外提供写服务，备选master（实际的slave，主机名server03）提供读服务，slave也提供相关的读服务，一旦master宕机，将会把备
   选备master提升为新的master，slave指向新的master,db250上部署Monitor（MHA Manager监控），主要是监控主从复制的集群中主库master是否正常，一旦master挂掉，MHA Manager会自动完成主库和slave从库的自动切换
   1.6 安装mysql
   Mater和slave都需要安装
   wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
   yum localinstall mysql57-community-release-el7-8.noarch.rpm
   yum install mysql-community-server -y
   systemctl enable mysqld
   systemctl daemon-reload
   systemctl start mysqld
   systemctl status mysqld
   grep 'temporary password' /var/log/mysqld.log
   mysql -uroot -p
   [root@server04 ~]# mysql -u root
   ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

service mysqld restart
192.168.52.251
vim /etc/my.cnf

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
character-set-server=utf8
server-id=1
log-bin=master-log
relay-log=relay-log
innodb_file_per_table = ON
skip_name_resolve = ON
max_connections = 5000#不在配置文件中限定只读，但是要记得在slave上限制只读

symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
192.168.52.252
vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
character-set-server=utf8
server-id=2
log-bin=master-log
relay-log=relay-log
relay_log_purge=0
read_only=1
skip_name_resolve=1
innodb_file_per_table=1
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
192.168.52.253
vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
character-set-server=utf8

server-id=3
log-bin=master-log
relay-log=relay-log
relay_log_purge=0
read_only=1
skip_name_resolve=1
innodb_file_per_table=1
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

第二：新建用户repl_user设置密码123456
重置root密码：123456

#更改密码
mysql -u root
#更改密码策略
set global validate_password_policy=0;
set global validate_password_length=4;
SET PASSWORD = PASSWORD('123456');
GRANT ALL PRIVILEGES ON . TO 'root'@'192.168.52.%' IDENTIFIED BY '123456' WITH GRANT OPTION;
flush privileges;
主从复制授权：
第三：在 3 个 mysql 节点做授权配置(主从复制授权)
Master:
grant replication slave,replication client on . to 'repluser'@'192.168.52.%' identified by '123456' ;
flush privileges;
#授权MHA管理用户-mhaadmin
grant all on . to 'mhaadmin'@'192.168.52.%' identified by 'mhapass' ;
flush privileges;
mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-log.000005 | 154 | | | |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
slave（两个从库）
#配置主从复制起点
change master to master_host='192.168.52.251',master_user='repluser',master_password='123456',master_log_file='master-log.000005',master_log_pos=154;
start slave;
show slave status\G
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
mysql> set global read_only=1; #查看slave IO和slave sql是否都正常
#查看主从复制情况
show grants for 'repluser'@'192.168.52.%';
mysql> flush privileges; #刷新权限
Query OK, 0 rows affected (0.00 sec)
删除多余用户
mysql> drop user root@'localhost';
mysql> select user,host from mysql.user;

1.7 ssh授信
配置三台机器的ssh互信（三台都要操作）
ssh-keygen -t rsa
ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]

#测试是否成功
ssh 192.168.52.251 date
1.8 安装MHA软件
安装MHA软件（在三个节点上都装mha的node软件）
#先安装依赖
wget http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
rpm -ivh epel-release-latest-7.noarch.rpm
yum install perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-Parallel-ForkManager　-y
下载软件
wget https://qiniu.wsfnk.com/mha4mysql-node-0.58-0.el7.centos.noarch.rpm
rpm -ivh mha4mysql-node-0.58-0.el7.centos.noarch.rpm

仅在manager节点上安装mha管理软件(192.168.52.250)
wget https://qiniu.wsfnk.com/mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
yum install perl-Parallel-ForkManager -y
rpm -ivh mha4mysql-manager-0.58-0.el7.centos.noarch.rpm

yum install mailx -y    #该软件是用来发送邮件的

-rwxr-xr-x 1 root root 5172 Jan 7 14:09 masterha_secondary_check
-rwxr-xr-x 1 root root 1739 Jan 7 14:09 masterha_stop
-rwxr-xr-x 1 root root 8337 Jan 7 14:14 purge_relay_logs
-rwxr-xr-x 1 root root 7525 Jan 7 14:14 save_binary_logs
1.9 配置MHA软件
192.168.52.250机器操作：

[root@db250 bin]# cd /usr/bin/
[root@db250 bin]# find ./ -name apply_diff_relay_logs
./apply_diff_relay_logs
[root@db250 bin]# cp /usr/bin/save_binary_logs /usr/local/bin/
[root@db250 bin]# cp /usr/bin/purge_relay_logs /usr/local/bin/
[root@db250 bin]# cp /usr/bin/filter_mysqlbinlog /usr/local/bin/
[root@db250 bin]# cp /usr/bin/apply_diff_relaylogs /usr/local/bin/
[root@db250 bin]# ln -s /usr/local/mysql/bin/mysql /usr/bin/mysql
[root@db250 bin]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/mysqlbinlog
[root@db250 bin]# cp -r /usr/bin/masterha* /usr/local/bin
[root@db250 bin]# cd /usr/local/bin/
[root@db250 bin]# ll
total 88
-rwxr-xr-x 1 root root 17639 Jan 7 14:14 apply_diff_relay_logs
-rwxr-xr-x 1 root root 4807 Jan 7 14:14 filter_mysqlbinlog
-rwxr-xr-x 1 root root 1995 Jan 7 14:09 masterha_check_repl
-rwxr-xr-x 1 root root 1779 Jan 7 14:09 masterha_check_ssh
-rwxr-xr-x 1 root root 1865 Jan 7 14:09 masterha_check_status
-rwxr-xr-x 1 root root 3201 Jan 7 14:09 masterha_conf_host
-rwxr-xr-x 1 root root 2517 Jan 7 14:09 masterha_manager
-rwxr-xr-x 1 root root 2165 Jan 7 14:09 masterha_master_monitor
-rwxr-xr-x 1 root root 2373 Jan 7 14:09 masterha_master_switch

MHA配置文件如下
mkdir -p /etc/masterha
[root@db250 app1]# cat /etc/masterha/app1.cnf
[server default]
manager_log=/var/log/masterha/app1/manager.log
manager_workdir=/var/log/masterha/app1.log
master_binlog_dir=/var/lib/mysql
master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
password=123456
ping_interval=1
remote_workdir=/tmp
repl_password=123456
repl_user=repluser
secondary_check_script=/usr/local/bin/masterha_secondary_check -s db251 -s db252 --user=root --master_host=db252 --master_ip=192.168.52.252 --master_port=3306
shutdown_script=""
ssh_port=22
ssh_user=root

[server1]
hostname=192.168.52.251
candidate_master=1
port=3306

[server2]
candidate_master=1
check_repl_delay=0
hostname=192.168.52.252
port=3306

[server3]
hostname=192.168.52.253
port=3306

二、设置relay log的清除方式（在每个slave节点上）：
三个节点服务器本地hosts解析
[root@db250 app1]# vim /etc/hosts
192.168.52.250 db250
192.168.52.251 db251
192.168.52.252 db252
192.168.52.253 db253

在slave master01 192.168.52.252操作：
[root@db251 ~]# mysql -uroot -p123456 -e "set global relay_log_purge=0"
mysql: [Warning] Using a password on the command line interface can be insecure.

在slave master02 192.168.52.253操作：
[root@ db252 ~]# mysql -uroot -p123456 -e "set global relay_log_purge=0"
mysql: [Warning] Using a password on the command line interface can be insecure.

注意：
MHA在发生切换的过程中，从库的恢复过程中依赖于relay log的相关信息，所以这里要将relay log的自动清除设置为OFF，采用手动清除relay log的方式。在默认情况下，从服务器上的中继日志会在SQL线程执行完毕后被自动删除。但是在MHA环境中，这些中继日志在恢复其他从服务器时可能会被用到，因此需要禁用中继日志的自动删除功能。定期清除中继日志需要考虑到复制延时的问题。在ext3的文件系统下，删除大的文件需要一定的时间，会导致严重的复制延时。为了避免复制延时，需要暂时为中继日志创建硬链接，因为在linux系统中通过硬链接删除大文件速度会很快。（在mysql数据库中，删除大表时，通常也采用建立硬链接的方式）

2.2设置定期清理relay脚本（两台slave服务器）：
[root@ db252~]# cat /data/scripts/purge_relay_log.sh
#!/bin/bash
user=root
passwd=123456
port=3306
log_dir='/data/masterha/log'
work_dir='/data'
purge='/usr/local/bin/purge_relay_logs'

if [ ! -d $log_dir ]
then
mkdir $log_dir -p
fi

$purge --user=$user --password=$passwd --disable_relay_log_purge --port=$port --workdir=$work_dir >> $log_dir/purge_relay_logs.log 2>

脚本介绍：
--user mysql //用户名
--password mysql //密码
--port //端口号
--workdir //指定创建relay log的硬链接的位置，默认是/var/tmp，由于系统不同分区创建硬链接文件会失败，故需要执行硬链接具体位置，成功执行脚本后，硬链接的中继日志文件被删除
--disable_relay_log_purge //默认情况下，如果relay_log_purge=1，脚本会什么都不清理，自动退出，通过设定这个参数，当relay_log_purge=1的情况下会将relay_log_purge设置为0。清理relay log之后，最后将参数设置为OFF。

purge_relay_logs脚本删除中继日志不会阻塞SQL线程。下面我们手动执行看看什么情况:
[root@ db252 ~]# purge_relay_logs --user=root --password=123456 --port=3306 -disable_relay_log_purge --workdir=/data/
2018-07-01 11:53:16: purge_relay_logs script started.
Found relay_log.info: /data/mysql/relay-log.info
Opening /data/mysql/logs/relay-log/relay-bin.000001 ..
Opening /data/mysql/logs/relay-log/relay-bin.000002 ..
Executing SET GLOBAL relay_log_purge=1; FLUSH LOGS; sleeping a few seconds so that SQL thread can delete older relay log files (if it keeps up); SET GLOBAL relay_log_purge=0; .. ok.
2018-07-01 11:53:20: All relay log purging operations succeeded.

主从failover脚本
[root@db250 app1]# cat /usr/local/bin/master_ip_failover
#!/usr/bin/env perl

#Copyright (C) 2011 DeNA Co.,Ltd.

#This program is free software; you can redistribute it and/or modify
#t under the terms of the GNU General Public License as published by
#the Free Software Foundation; either version 2 of the License, or
#(at your option) any later version.

#This program is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#GNU General Public License for more details.
#You should have received a copy of the GNU General Public License
#along with this program; if not, write to the Free Software
#Foundation, Inc.,
#51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

##Note: This is a sample script and is not complete. Modify the script based on your environment.
######################################################
use strict;
use warnings FATAL => 'all';

use Getopt::Long;
use MHA::DBHelper;

my (
$command, $ssh_user, $orig_master_host,
$orig_master_ip, $orig_master_port, $new_master_host,
$new_master_ip, $new_master_port, $new_master_user,
$new_master_password
);
my $vip = '192.168.52.199';
my $ssh_start_vip = "systemctl start keepalived";
my $ssh_stop_vip = "systemctl stop keepalived ";

GetOptions(
'command=s' => \$command,
'ssh_user=s' => \$ssh_user,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
'new_master_user=s' => \$new_master_user,
'new_master_password=s' => \$new_master_password,
);

exit &main();

sub main {

print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";

if ( $command eq "stop" || $command eq "stopssh" ) {

#$orig_master_host, $orig_master_ip, $orig_master_port are passed.
#If you manage master ip address at global catalog database,
#invalidate orig_master_ip here.
my $exit_code = 1;
eval {
  print "Disabling the VIP on old master: $orig_master_host \n";
  &stop_vip();
  #updating global catalog, etc
  $exit_code = 0;
};
if ($@) {
  warn "Got Error: $@\n";
  exit $exit_code;
}
exit $exit_code;

}
elsif ( $command eq "start" ) {

#all arguments are passed.
#If you manage master ip address at global catalog database,
#activate new_master_ip here.
#You can also grant write access (create user, set read_only=0, etc) here.
my $exit_code = 10;
eval {
  print "Enabling the VIP - $vip on the new master - $new_master_host \n";
  &start_vip();
  $exit_code = 0;
    };
if ($@) {
  warn $@;

  #If you want to continue failover, exit 10.
  exit $exit_code;
}
exit $exit_code;

}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. OK \n";
#do nothing
exit 0;
}
else {
&usage();
exit 1;
}
}

sub start_vip() {
ssh $ssh_user\@$new_master_host \" $ssh_start_vip \";
}

#A simple system call that disable the VIP on the old_master
sub stop_vip() {
ssh $ssh_user\@$orig_master_host \" $ssh_stop_vip \";
}

sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}

chmod +x /usr/local/bin/master_ip_failover

1.10 MHA相关测试
测试SSH免密码登录
masterha_check_ssh --conf=/etc/masterha/app1.cnf

测试MHA数据库同步
masterha_check_repl --conf=/etc/masterha/app1.cnf
chmod +x /usr/local/bin/masterha_check_repl

查看MHA Manager监控是否正常：
masterha_check_status --conf=/etc/masterha/app1.cnf

关闭MHA Manage监控
masterha_stop --conf=/etc/masterha/app1.cnf

1.11 启动mha数据监控
masterha_check_status --conf=/etc/masterha/app1.cnf
mkdir -p /var/log/masterha/app1/

nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/masterha/app1/manager.log 2>&1 &
ps -ef|grep perl

1.12 配置vip实现MHA架构中主库故障自动切换
192.168.52.251和192.168.52.252
Yum install keepalived -y

192.168.52.251
[root@db251 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {br/>[email protected]
}
notification_email_from [email protected]
smtp_server 192.168.52.251
smtp_connect_timeout 30
router_id LVS_01
}

vrrp_instance VI_1 {
#state MASTER
state BACKUP
interface ens33
virtual_router_id 51
priority 100
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.2.199/24
}
}

systemctl start keepalived

192.168.52.252
[root@db252 ~]# vim /etc/keepalived/keepalived.conf

global_defs {
notification_email {br/>[email protected]
}
notification_email_from [email protected]
smtp_server 192.168.52.252
smtp_connect_timeout 30
router_id LVS_01
}**

vrrp_instance VI_1 {
#state MASTER
state BACKUP
interface ens33
virtual_router_id 51
priority 90
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.52.199/24
}
}

systemctl start keepalived

#####特别注意！！！！！
上面两台服务器的keepalived都设置为了BACKUP模式，在keepalived中2种模式，分别是master->backup模式和backup->backup模式。这两种模式有很大区别。在master->backup模式下，一旦主库宕机，虚拟ip会自动漂移到从库，当主库修复后，keepalived启动后，还会把虚拟ip抢占过来，即使设置了非抢占模式（nopreempt）抢占ip的动作也会发生。在backup->backup模式下，当主库宕机后虚拟ip会自动漂移到从库上，当原主库恢复和keepalived服务启动后，并不会抢占新主的虚拟ip，即使是优先级高于从库的优先级别，也不会发生抢占。为了减少ip漂移次数，通常是把修复好的主库当做新的备库。
++++到此处MHA架构中keepalived服务安装配置完成++++

1.13检查故障切换后MHA集群相关服务的变化
配置文件/etc/masterha/app1.cnf变化
1、在db250 192.168.52.250管理节点查看一下配置文件/etc/masterha/app1.cnf可以发现[server1]的内容已经被自动去掉了：
2、masterha_manager 服务自动退出
3、源master192.168.52.251机器上keepalived服务被停掉了
4、查看日志/var/log/masterha/app1/manager.log

#######重要提示！！！
当db251 192.168.52.251 机器上的mysql挂掉后，db252 192.168.52.252机器提升为master时，192.168.52.251 机器上的keepalived会停掉，而 192.168.52.252机器的keepalived会开启，VIP票到199机器上。
此时需要重启192.168.52.251上的mysql,一般都是要恢复它作为252新主的从库，此时192.168.52.251机器上的keepalived千万不要开启，因为开启keepalived，会抢占252机器上的VIP,导致程序连接数据库出现混乱。同时192.168.52.251机器和192.168.52.252机器上的keepalived服务不要设置为开机自启动
1.14 mha高可用重新加入监控
1、出问题的master:
show master status;

Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs;
these UUIDs must be different for replication to work.

2、解决方法：
rm -rf /var/lib/mysql/auto.cnf
systemctl restart mysqld

3、数据库从库同步主库

show master status；
#配置主从复制起点

change master to master_host='192.168.52.251',master_user='repluser',master_password='123456',master_log_file='master-log.000004',master_log_pos=154; #注意masterIP地址
start slave;
show slave status\G

4、切换完毕后缺少

secondary_check_script=/usr/local/bin/masterha_secondary_check -s db251 -s db252 --user=root --master_host=db252 --master_ip=192.168.52.252 --master_port=3306

添加：
[server1]
hostname=192.168.52.252
candidate_master=1
port=3306

5、测试
测试ssh
masterha_check_ssh --conf=/etc/masterha/app1.cnf

测试MHA数据库同步，并自动启动
masterha_check_repl --conf=/etc/masterha/app1.cnf

查看MHA Manager监控是否正常：
masterha_check_status --conf=/etc/masterha/app1.cnf

6、日志查看
tailf /var/log/masterha/app1/manager.log

7、开启MHA Manager监控
nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/masterha/app1/manager.log 2>&1 &

8、查询manger程序

ps -ef|grep perl
1.15 安装配置LVS+keepalived
192.168.52.251（backup_master）和192.168.52.252（slave）
[root@db251 ~]# vi /etc/rc.d/init.d/realserver
#!/bin/sh
# chkconfig: - 80 90
# description:realserver
# mysql_vip start realserver*
mysql_vip=192.168.52.199
. /etc/rc.d/init.d/functions
case "$1" in
start)
ifconfig lo:0 $mysql_vip netmask 255.255.255.255 broadcast $mysql_vip
/sbin/route add -host $mysql_vip dev lo:0
echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
sysctl -p >/dev/null 2>&1
echo "RealServer Start OK"
;;
stop)
ifconfig lo:0 down
route del $mysql_vip >/dev/null 2>&1
echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "RealServer Stoped"
;;
)
echo "Usage: $0 {start|stop}"
exit 1
esac
exit 0

chmod +x /etc/rc.d/init.d/realserver #添加脚本执行权限
chkconfig realserver on #添加开机启动
/etc/rc.d/init.d/realserver start #开启，参数stop为关闭

Lvs01-192.168.52.248,配置文件249和248一致
[root@lvs248 ~]# yum install ipvsadm keepalived gcc gcc-c++ make openssl-devel kernel-devel ncurses-devel -y
[root@lvs248 ~]# lsmod |grep ip_vs
ip_vs 141432 0
nf_conntrack 133053 1 ip_vs
libcrc32c 12644 3 xfs,ip_vs,nf_conntrack
[root@lvs248 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf-bak
[root@lvs248 ~]# >/etc/keepalived/keepalived.conf
[root@lvs248 ~]# vim /etc/keepalived/keepalived.conf

    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
    auth_type PASS
    auth_pass 1111
    }

    virtual_ipaddress {
            192.168.52.159
    }

}

virtual_server 192.168.52.159 3306 {

            delay_loop 6
            lb_algo wlc
            lb_kind DR
            #persistence_timeout 120
            protocol TCP

    real_server 192.168.52.252 3306 {

            weight 1
            TCP_CHECK {
                    connect_timeout 3
                    nb_get_retry 3
                    delay_before_retry 3
                    connect_port 3306
            }
            MISC_CHECK {
                     misc_path "/etc/keepalived/check_slave.py 192.168.52.252 3306"
                     misc_dynamic

}
}

    real_server 192.168.52.253 3306 {

            weight 1
            TCP_CHECK {
                    connect_timeout 3
                    nb_get_retry 3
                    delay_before_retry 3
                    connect_port 3306
    }
             MISC_CHECK {
                     misc_path "/etc/keepalived/check_slave.py 192.168.52.253 3306"
                     misc_dynamic
    }
}

}

[root@lvs248 keepalived]# pwd
/etc/keepalived
[root@lvs248 keepalived]# ll
total 12
-rw-r--r-- 1 root root 816 Jan 11 11:05 check_slave.py
-rw-r--r-- 1 root root 1489 Jan 11 11:35 keepalived.conf
-rw-r--r-- 1 root root 3598 Jan 11 10:01 keepalived.conf-bak

vim /etc/keepalived/check_slave.py
#!/usr/bin/env python
#encoding:utf-8
import MySQLdb
import sys
ip=sys.argv[1]
user='repluser'
pwd='123456'
port=int(sys.argv[2])
sbm=200
Slave_IO_Running = ''
Slave_SQL_Running = ''
Seconds_Behind_Master = ''
e=''
try:
conn = MySQLdb.connect(host=ip,user=user,passwd=pwd,port=port,charset='utf8')
cur = conn.cursor()
cur.execute('show slave status')
db_info = cur.fetchall()
for n in db_info:
Slave_IO_Running = n[10]
Slave_SQL_Running = n[11]
Seconds_Behind_Master = n[32]
cur.close()
conn.close()
except MySQLdb.Error,e:
print "MySQLdb Error",e
ife == "":
ifdb_info != ():
ifSlave_IO_Running == "No" or Slave_SQL_Running == "No":
#print 'thread err'
exit(1)
else:
ifSeconds_Behind_Master > sbm:
#print 'timeout err'
exit(1)
else:
#print 'OK'
exit(0)
else:
#print 'slave err'
exit(1)
else:
#print 'db err'
exit(1)
~

[root@lvs248 keepalived]# systemctl start keepalived
[root@lvs248 keepalived]# systemctl status keepalived
[root@lvs248 keepalived]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.52.199:3306 wlc
-> 192.168.52.252:3306 Route 1 0 0
-> 192.168.52.253:3306 Route 1 0 0
1.16 测试
测试 read vip 负载均衡
分别在从库 db252、 db253、 创建可区分的库，库名分别为
read_one、 read_two
# db252
mysql> create database read_one;
Query OK, 1 row affected (0.00 sec)
mysql> show databases like 'read_one';
+---------------------+
| Database (read_one) |
+---------------------+
| read_one |
+---------------------+
1 row in set (0.00 sec)
# db252 操作略
[root@db251 ~]# mysql -uroot -p123456 -h 192.168.52.159 -P3306 -e "show databases"|egrep -v "schema|mysql|test|Database"
mysql: [Warning] Using a password on the command line interface can be insecure.
read_one
read_two
sys
[root@db251 ~]# mysql -uroot -p123456 -h 192.168.52.159 -P3306 -e "show databases"|egrep -v "schema|mysql|test|Database"
mysql: [Warning] Using a password on the command line interface can be insecure.
read_one
sys

测试从库故障被剔除，恢复被挂起
将 db253 数据库关闭，观察 lvs 状态
#lvs 未关闭 mysql 时的状态
[root@master1 keepalived]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.52.159:3306 wlc
-> 192.168.52.252:3306 Route 1 0 0
-> 192.168.52.253:3306 Route 1 0 0
[root@master1 keepalived]# msyql -uroot -h 192.168.52.159 -p
-bash: msyql: command not found
[root@master1 keepalived]# mysql -uroot -h 192.168.52.159 -p
Enter password:
^Z
[1]+ Stopped mysql -uroot -h 192.168.52.159 -p
#lvs 关闭 mysql 后的状态
[root@master1 keepalived]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.52.159:3306 wlc
-> 192.168.52.252:3306 Route 1 0 0

注：数据库开启后，会自动加入到节点中
[root@master1 keepalived]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.52.159:3306 wlc
-> 192.168.52.252:3306 Route 1 0 0
-> 192.168.52.253:3306 Route 1 0 0

测试 keepalived 高可用 vip 切换
192.168.52.248
[root@lvs248 keepalived]# systemctl stop keepalived

192.168.52.249
[root@lvs249 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.52.159:3306 wlc
-> 192.168.52.252:3306 Route 1 0 0
-> 192.168.52.253:3306 Route 1 0 0

192.168.52.249
[root@lvs249 keepalived]# systemctl stop keepalived

192.168.52.248
[root@lvs248 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.52.159:3306 wlc
-> 192.168.52.252:3306 Route 1 0 0
-> 192.168.52.253:3306 Route 1 0 0

1.17 报错日志和解决方法
报错日志：
[root@ MHA]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/mysqlbinlog
12345678910111213 Binlog found at /log/mysql, up to mysql-bin.000009
Tue Apr 5 22:43:55 2016 - [info] Binlog setting check done.
Tue Apr 5 22:43:55 2016 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Tue Apr 5 22:43:55 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='root' --slave_host=192.168.1.248 --slave_ip=192.168.1.248 --slave_port=4008 --workdir=/usr/local/mha --target_version=5.6.16-log --manager_version=0.57 --relay_log_info=/data/mysql/relay-log.info --relay_dir=/data/mysql/ --slave_pass=xxx
Tue Apr 5 22:43:55 2016 - [info] Connecting to [email protected](192.168.1.248:22)..
mysqlbinlog: unknown variable 'default-character-set=utf8'
mysqlbinlog version command failed with rc 7:0, please verify PATH, LD_LIBRARY_PATH, and client options
at /usr/local/bin/apply_diff_relay_logs line 493
Tue Apr 5 22:43:55 2016 - [error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln205] Slaves settings check failed!
Tue Apr 5 22:43:55 2016 - [error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln413] Slave configuration failed.
Tue Apr 5 22:43:55 2016 - [error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln424] Error happened on checking configurations. at /usr/local/bin/masterha_check_repl line 48
Tue Apr 5 22:43:55 2016 - [error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln523] Error happened on monitoring servers.
Tue Apr 5 22:43:55 2016 - [info] Got exit code 1 (Not master dead).
解决方案
注释掉my.cnf中的
[client]
#default-character-set=utf8
报错2：
[root@db52 ~]# tailf /var/log/mysqld.log
2019-01-10T03:10:01.260664Z 0 [ERROR] Error during --relay-log-recovery: Could not locate rotate event from the master.
2019-01-10T03:10:01.294452Z 0 [Note] InnoDB: Buffer pool(s) load completed at 190110 11:10:01
2019-01-10T03:10:01.294559Z 0 [ERROR] Slave: Failed to initialize the master info structure for channel ''; its record may still be present in 'mysql.slave_master_info' table, consider deleting it.
2019-01-10T03:10:01.294590Z 0 [ERROR] Failed to create or recover replication info repositories.
2019-01-10T03:10:01.294599Z 0 [Note] Some of the channels are not created/initialized properly. Check for additional messages above. You will not be able to start replication on those channels until the issue is resolved and the server restarted.
2019-01-10T03:10:01.301143Z 0 [Note] Event Scheduler: Loaded 0 events
2019-01-10T03:10:01.301320Z 0 [Note] /usr/sbin/mysqld: ready for connections.
解决方法：
mysql> reset slave;
Query OK, 0 rows affected (0.31 sec)
mysql> change master to master_host='192.168.20.52',master_user='repluser',master_password='123456',master_log_file='master-log.000015',master_log_pos=2923;
Query OK, 0 rows affected, 2 warnings (0.32 sec)
mysql> start slave;
Query OK, 0 rows affected (0.51 sec)
报错3：
Got fatal error 1236 from master when reading data from binary log: 'Could not find first log file name in binary log index file'

解决方法：
/usr//bin/mysqlbinlog --start-position=2923 /var/lib/mysql/mysql-bin.000015