MHA群集管理

MHA群集管理

环境:

192.168.205.37: as MHA server
192.168.205.47: as Master server
192.168.205.57: as Slave1 server
192.168.205.67: as Slave2 server

版本:

OS: centos 7 1810 with mini install
mariadb-server 5.5.60
mha4mysql-manager-0.56-0.el6.noarch.rpm
mha4mysql-node-0.56-0.el6.noarch.rpm

目地:

MHA使用perl脚本写的程序,当主节点down时如果从节点复制没有完成时,当他成为主节点后,它需要尝试将主节点的二进制日志复制到新的主节点,从而保证数据的完整性,所以它需要sshkey验证。我们使用一台做为管理节点,其中三个为数据库节点,一主两从,模拟主节点down机,看从是如何被提升为主节点的。

安装数据库

  1. 安装mariadb使用如下脚本:
    [[email protected] data]#cat maridb_yum.sh 
    #!/bin/bash
    ID=`ip a show dev eth0 | sed -r '3!d;[email protected](.*inet)(.*)(/.*)@\[email protected]' | cut -d. -f4`
    rpm -q mariadb-server ||yum install -y mariadb-server
    [ -d /data/mysql ] || mkdir -p /data/mysql
    [ -d /data/logs ] || mkdir -p /data/logs
    chown mysql:mysql /data/{mysql,logs}
    sed -i '[email protected]=/var/lib/[email protected]=/data/[email protected]' /etc/my.cnf
    grep "log-bin" /etc/my.cnf || sed -i '/\[mysqld\]/a log-bin=/data/logs/bin' /etc/my.cnf
    grep "innodb_file_per_table" /etc/my.cnf || sed -i '/\[mysqld\]/a innodb_file_per_table = on' /etc/my.cnf
    grep "skip_name_resolve" /etc/my.cnf || sed -i '/\[mysqld\]/a skip_name_resolve = on' /etc/my.cnf
    grep "server-id" /etc/my.cnf || sed -i "/\[mysqld\]/a server-id=$ID" /etc/my.cnf
    service mariadb restart
  2. 修改两个从节点的配置文件
    [[email protected] data]#vi /etc/my.cnf
    [mysqld]
    read_only   
    relay_log_purge=0     #不删除中继日志
  3. 建立主节点的复制位置和帐号

    MariaDB [(none)]> show master logs;
    +------------+-----------+
    | Log_name   | File_size |
    +------------+-----------+
    | bin.000001 |     30373 |
    | bin.000002 |   1038814 |
    | bin.000003 |       245 |
    +------------+-----------+
    3 rows in set (0.00 sec)
    
    MariaDB [(none)]> grant replication slave on *.* to [email protected]'192.168.205.%' identified by 'centos';
    Query OK, 0 rows affected (0.00 sec)
    MariaDB [(none)]> grant all on *.* to [email protected]'192.168.205.%' identified by 'centos'; 
    Query OK, 0 rows affected (0.00 sec)
  4. 配置从节点的change master to并启动线程

    MariaDB [(none)]> CHANGE MASTER TO
        ->   MASTER_HOST='192.168.205.47',
        ->   MASTER_USER='repluser',
        ->   MASTER_PASSWORD='centos',
        ->   MASTER_PORT=3306,
        ->   MASTER_LOG_FILE='bin.000003',
        ->   MASTER_LOG_POS=245;
    Query OK, 0 rows affected (0.01 sec)
    
    MariaDB [(none)]> start slave;
    Query OK, 0 rows affected (0.00 sec)
    MariaDB [(none)]> show slave status\G
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 192.168.205.47
                      Master_User: repluser
                      Master_Port: 3306
                    Connect_Retry: 60
                  Master_Log_File: bin.000003
              Read_Master_Log_Pos: 401
                   Relay_Log_File: mariadb-relay-bin.000002
                    Relay_Log_Pos: 679
            Relay_Master_Log_File: bin.000003
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes

    MHA实现

  5. 安装包,mha依赖epel源,我们要把epel起用
    [[email protected] ~]#yum install mha4mysql-manager-0.56-0.el6.noarch.rpm mha4mysql-node-0.56-0.el6.noarch.rpm 
  6. 在所有的sql节点上安装node包
    [[email protected] ~]#yum install mha4mysql-node-0.56-0.el6.noarch.rpm 
    [[email protected] data]#yum install mha4mysql-node-0.56-0.el6.noarch.rpm 
    [[email protected] data]#yum install mha4mysql-node-0.56-0.el6.noarch.rpm 
  7. 配置ssh key 验证
    [[email protected] ~]#ssh-keygen 
    [[email protected] ~]#ssh-copy-id 192.168.205.37
    [[email protected] ~]#cat .ssh/authorized_keys 
    [[email protected] ~]#scp -r .ssh 192.168.205.47:/root/
    [[email protected] ~]#scp -r .ssh 192.168.205.57:/root/
    [[email protected] ~]#scp -r .ssh 192.168.205.67:/root/
  8. 生成配置MHA文件
    [[email protected] ~]#mkdir /etc/mha
    [[email protected] ~]#vim /etc/mha/app1.cnf
    [server default]
    master_binlog_dir=/data/logs/ 
    user=mhauser
    password=centos
    manager_workdir=/data/mastermha/app1/
    manager_log=/data/mastermha/app1/manager.log
    remote_workdir=/data/mastermha/app1/
    ssh_user=root
    repl_user=repluser
    repl_password=centos
    ping_interval=1
    [server1]
    hostname=192.168.205.47
    candidate_master=1
    [server2]                                                                                                                          
    hostname=192.168.205.57
    [server3]
    hostname=192.168.205.67
    candidate_master=1
  9. 启动之前进行检查ssh,repl复制是否准备好
    [[email protected] ~]#masterha_check_ssh --conf=/etc/mha/app1.cnf
    [[email protected] ~]#masterha_check_repl --conf=/etc/mha/app1.cnf
  10. 起动进程,此进程前台运行,当主节点失败时切换完成后它会终止,所以要想持续要重启进程
    [[email protected] ~]#masterha_manager --conf=/etc/mha/app1.cnf
    Mon Aug 12 23:33:22 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
    Mon Aug 12 23:33:22 2019 - [info] Reading application default configuration from /etc/mha/app1.cnf..
    Mon Aug 12 23:33:22 2019 - [info] Reading server configuration from /etc/mha/app1.cnf..

    测试

  11. 我们模拟一个正在写入操作时,主节点down, 看服务器能不能正常切换并不能复制丢失的数据

    MariaDB [(none)]> use test;
    Database changed
    MariaDB [test]> create table testlog (id int auto_increment primary key,name char(10),age int default 20);
    
    Query OK, 0 rows affected (0.01 sec)
    
    MariaDB [test]> 
    MariaDB [test]> delimiter $$
    MariaDB [test]> 
    MariaDB [test]> create procedure  sp_testlog() 
        -> begin  
        -> declare i int;
        -> set i = 1; 
        -> while i <= 100000 
        -> do  insert into testlog(name,age) values (concat('wang',i),i); 
        -> set i = i +1; 
        -> end while; 
        -> end$$
    Query OK, 0 rows affected (0.00 sec)
    
    MariaDB [test]> 
    MariaDB [test]> delimiter ;
    MariaDB [test]> call sp_testlog;
  12. 正在写入数据时我们及时关闭47服务器,MHA检测到节点,并响应,成功提升其它的为主后退出程序。
    [[email protected] ~]#masterha_manager --conf=/etc/mha/app1.cnf
    Mon Aug 12 23:33:22 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
    Mon Aug 12 23:33:22 2019 - [info] Reading application default configuration from /etc/mha/app1.cnf..
    Mon Aug 12 23:33:22 2019 - [info] Reading server configuration from /etc/mha/app1.cnf..
    Mon Aug 12 23:45:16 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
    Mon Aug 12 23:45:16 2019 - [info] Reading application default configuration from /etc/mha/app1.cnf..
    Mon Aug 12 23:45:16 2019 - [info] Reading server configuration from /etc/mha/app1.cnf..
    [[email protected] ~]#
  13. 我们可以查看日志看一下发生的情况,slave2提升为主

    [[email protected] data]#cat mastermha/app1/manager.log 
    ----- Failover Report -----
    
    app1: MySQL Master failover 192.168.205.47(192.168.205.47:3306) to 192.168.205.67(192.168.205.67:3306) succeeded
    
    Master 192.168.205.47(192.168.205.47:3306) is down!
    
    Check MHA Manager logs at MHA:/data/mastermha/app1/manager.log for details.
    
    Started automated(non-interactive) failover.
    The latest slave 192.168.205.57(192.168.205.57:3306) has all relay logs for recovery.
    Selected 192.168.205.67(192.168.205.67:3306) as a new master.
    192.168.205.67(192.168.205.67:3306): OK: Applying all logs succeeded.
    192.168.205.57(192.168.205.57:3306): This host has the latest relay log events.
    Generating relay diff files from the latest slave succeeded.
    192.168.205.57(192.168.205.57:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.205.67(192.168.205.67:3306)
    192.168.205.67(192.168.205.67:3306): Resetting slave info succeeded.
    Master failover to 192.168.205.67(192.168.205.67:3306) completed successfully.
  14. 我们来核实一下,在slave2上看一下slave的状态,发现已经没了,因为它是主
    MariaDB [(none)]> show slave status\G
    Empty set (0.00 sec)
  15. 检查一下slave1,发现主节点指向了slave2
    MariaDB [test]> show slave status\G
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 192.168.205.67
                      Master_User: repluser
                      Master_Port: 3306
                    Connect_Retry: 60
                  Master_Log_File: bin.000005
              Read_Master_Log_Pos: 245
                   Relay_Log_File: mariadb-relay-bin.000002
                    Relay_Log_Pos: 523
            Relay_Master_Log_File: bin.000005
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes
  16. 在新主节点上看一下是否将read_only off掉,发现是,但不要忘记改回配置文件,如果重启的话又会变成read_only
    MariaDB [(none)]> show variables like 'read_only';
    +---------------+-------+
    | Variable_name | Value |
    +---------------+-------+
    | read_only     | OFF   |
    +---------------+-------+
    1 row in set (0.00 sec)

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转载自blog.51cto.com/127601/2428895
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