MHA—MySQL 主从之Master高可用

MHA—MySQL 主从之Master高可用

实验准备工作

• 主机角色划分：

192.168.50.9     node9      MySQL主节点
192.168.50.10    node10     MySQL从节点
192.168.50.16    node16     MySQL从节点
192.168.50.17  172.16.50.17  node17     MasterHA Manager & ProxySQL

1. 主节点

#修改配置文件
vim /etc/my.cnf.d/server.cnf
[mysqld]
innodb_file_per_table=ON
skip_name_resolve=ON

server_id=1
log_bin=master-log
relay_log=relay-log
#重启服务
systemctl restart mariadb

1. 两个从节点分别执行(不同主机注意修改自己的server_id)

#修改配置文件
vim /etc/my.cnf.d/server.cnf
[mysqld]
innodb_file_per_table=ON
skip_name_resolve=ON

server_id=2
relay_log=relay-log
log_bin=master-log
relay_log_purge=0
read-only=1
#重启服务
systemctl restart mariadb

1. 创建ssh密钥，使任意两台主机间能够通过ssh自由通信

此处为了操作简单，可以使所有主机的密钥相同，具体做法为：在任意一台主机上生成一对密钥，将密钥发送至所有主机的对应目录下

#假如在node9节点主机上执行
ssh-keygen -t rsa -P ''
ssh-copy-id -i id_rsa.pub root@192.168.50.9
#测试ssh连接可用性并更新know_hosts文件内容
ssh root@192.168.50.9 'ip a'
ssh root@192.168.50.10 'ip a'
ssh root@192.168.50.16 'ip a'
ssh root@192.168.50.17 'ip a'
#
scp -p id_rsa authorized_keys id_rsa.pub known_hosts root@192.168.50.10:/root/.ssh/
scp -p id_rsa authorized_keys id_rsa.pub known_hosts root@192.168.50.16:/root/.ssh/
scp -p id_rsa authorized_keys id_rsa.pub known_hosts root@192.168.50.17:/root/.ssh/

1. 获取mha4mysql-manager和mha4mysql-node两个程序包并安装

   • 在manager主机上需要同时安装manager和node包

yum install ./mha4mysql-manager-0.56-0.el6.noarch.rpm ./mha4mysql-node-0.56-0.el6.noarch.rpm

• 在node主机上仅需安装mha4mysql-node包

yum install ./mha4mysql-node-0.56-0.el6.noarch.rpm

1. 初始化MHA

因为192.168.50.16从节点主机未开启日志同步，故此处仅设置192.168.50.10作为主节点的备用节点

#创建目录
mkdir /etc/masterha
#创建、修改并增加配置文件内容
vim /etc/masterha/app1.cnf
[server default]
user=mhaadmin
password=mhapass
manager_workdir=/data/masterha/app1
manager_log=/data/masterha/app1/manager.log
remote_workdir=/data/masterha/app1
ssh_user=root
repl_user=repladmin
repl_password=replpass
ping_interval=1

[server1]
hostname=192.168.50.9
candidate_master=1

[server2]
hostname=192.168.50.10
candidate_master=1

[server3]
hostname=192.168.50.16
candidate_master=0

1. 在node9主节点服务器上为mha创建并授权用户

GRANT ALL ON *.* TO 'mhaadmin'@'192.168.50.%' IDENTIFIED BY 'mhapass';
GRANT ALL ON *.* TO 'repladmin'@'192.168.50.%' IDENTIFIED BY 'replpass';
FLUSH PRIVILEGES;

1. 验证各主机是否可以基于ssh实现自由通信

masterha_check_ssh --conf=/etc/masterha/app1.cnf
#成功信息
[info] All SSH connection tests passed successfully

1. 对各mysql主机进行健康状态监测

masterha_check_repl --conf=/etc/masterha/app1.cnf
#成功信息
MySQL Replication Health is OK.

1. 启动进程

nohup masterha_manager --conf=/etc/masterha/app1.cnf &>> /data/masterha/app1/manager.log &

1. 监测状态

masterha_check_status --conf=/etc/masterha/app1.cnf 
#显示结果
app1 (pid:4663) is running(0:PING_OK), master:192.168.50.9

1. 验证failover效果

   • 在node9上停止mysql服务

killall -9 mysqld mysqld_safe

• 在mha主机上会出现以下提示

[1]+  Done                    nohup masterha_manager --conf=/etc/masterha/app1.cnf &>>/data/masterha/app1/manager.log

• 查看mha日志

less /data/masterha/app1/manager.log
#出现如下内容
----- Failover Report -----

app1: MySQL Master failover 192.168.50.9(192.168.50.9:3306) to 192.168.50.10(192.168.50.10:3306) succeeded

Master 192.168.50.9(192.168.50.9:3306) is down!

Check MHA Manager logs at localhost.localdomain:/data/masterha/app1/manager.log for details.

Started automated(non-interactive) failover.
The latest slave 192.168.50.10(192.168.50.10:3306) has all relay logs for recovery.
Selected 192.168.50.10(192.168.50.10:3306) as a new master.
192.168.50.10(192.168.50.10:3306): OK: Applying all logs succeeded.
192.168.50.16(192.168.50.16:3306): This host has the latest relay log events.
Generating relay diff files from the latest slave succeeded.
192.168.50.16(192.168.50.16:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.50.10(192.168.50.10:3306)
192.168.50.10(192.168.50.10:3306): Resetting slave info succeeded.
Master failover to 192.168.50.10(192.168.50.10:3306) completed successfully.

• 修改node2（新的主节点）数据库的内容，从节点会同步执行

  1. 停止MHA的方法：

masterha_stop --conf=/etc/masterha/app1.cnf