MySQL Group Replication 动态添加成员节点

野性酷女 2022-07-13 10:29 109阅读 0赞

# 1. 背景 #

前面文章已经介绍如何部署MySQL GR 的两种模式:

*  [MySQL Group Replication 搭建 (Multi-Primary Mode)][MySQL Group Replication _ _Multi-Primary Mode]
 *  [MySQL Group Replication 搭建 (Single-Primary Mode)][MySQL Group Replication _ _Single-Primary Mode]

在前面的部署里面，因为是预先知道需要部署的组节点规模，所以我们能够在my.cnf里面体现出组成员信息。但是，前面的部署并没有体现出动态添加组节点。

这篇文章介绍如何动态地往一个组里面添加新的成员。

**前提**: MySQL GR 3节点（s1、s2、s3）部署成功，模式定为Multi-Primary Mode，Single-Primary Mode也是一样的处理。

**目标**: 不重启已有GR节点的基础上，添加新成员s4、s5，组成5节点的GR。

# 2. 部署过程 #

> 假设已经通过3节点的部署(部署参考上面的博客)

## 2.1 在线修改已有GR节点配置 ##

**分别登陆s1、s2、s3，执行以下命令，修改GR配置**:

mysql> set global group_replication_group_seeds="127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903,127.0.0.1:24904,127.0.0.1:24905";
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> show variables like '%group_replication_group_seeds%';
    +-------------------------------+---------------------------------------------------------------------------------+
    | Variable_name                 | Value                                                                           |
    +-------------------------------+---------------------------------------------------------------------------------+
    | group_replication_group_seeds | 127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903,127.0.0.1:24904,127.0.0.1:24905 |
    +-------------------------------+---------------------------------------------------------------------------------+
    1 row in set (0.00 sec)

## 2.2 部署s4 ##

安装s4:

mysql-5.7/bin/mysqld --initialize-insecure --basedir=$PWD/mysql-5.7 --datadir=$PWD/data/s4

增加配置s4.cnf:

# server configuration
    [mysqld]
    datadir=/dba/mysql/data/s4
    basedir=/dba/mysql/mysql-5.7/
    
    port=24804
    socket=/dba/mysql/data/s4/s4.sock
    
    server_id=4
    gtid_mode=ON
    enforce_gtid_consistency=ON
    master_info_repository=TABLE
    relay_log_info_repository=TABLE
    binlog_checksum=NONE
    log_slave_updates=ON
    log_bin=binlog
    binlog_format=ROW
    
    transaction_write_set_extraction=XXHASH64
    loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
    loose-group_replication_start_on_boot=off
    loose-group_replication_local_address= "127.0.0.1:24904"
    loose-group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903,127.0.0.1:24904,127.0.0.1:24905"
    loose-group_replication_bootstrap_group= off
    loose-group_replication_single_primary_mode=false
    loose-group_replication_enforce_update_everywhere_checks=true

启动s4:

nohup mysql-5.7/bin/mysqld --defaults-file=data/s4/s4.cnf >data/s4/nohup.out 2>data/s4/nohup.out &

使用以下命令登陆s4:

mysql -uroot -h127.0.0.1 -P24804 --skip-password

修改root密码:

SET SQL_LOG_BIN=0;
    ALTER USER 'root'@'localhost' IDENTIFIED BY 'mysql';
    SET SQL_LOG_BIN=1;

创建gr所需要用户并授权:

SET SQL_LOG_BIN=0;
    CREATE USER rpl_user@'%';
    GRANT REPLICATION SLAVE ON *.* TO rpl_user@'%' IDENTIFIED BY 'rpl_pass';
    FLUSH PRIVILEGES;
    SET SQL_LOG_BIN=1;
    CHANGE MASTER TO MASTER_USER='rpl_user', MASTER_PASSWORD='rpl_pass' FOR CHANNEL 'group_replication_recovery';

安装组复制插件并开启插件

INSTALL PLUGIN group_replication SONAME 'group_replication.so';
    
    START GROUP_REPLICATION;

验证s4已经加入GR集群:

## 2.3 部署s5 ##

与s4相同的部署即可以将s5加入GR集群:

s5.cnf配置:

# server configuration
    [mysqld]
    datadir=/dba/mysql/data/s5
    basedir=/dba/mysql/mysql-5.7/
    
    port=24805
    socket=/dba/mysql/data/s5/s5.sock
    
    server_id=5
    gtid_mode=ON
    enforce_gtid_consistency=ON
    master_info_repository=TABLE
    relay_log_info_repository=TABLE
    binlog_checksum=NONE
    log_slave_updates=ON
    log_bin=binlog
    binlog_format=ROW
    
    transaction_write_set_extraction=XXHASH64
    loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
    loose-group_replication_start_on_boot=off
    loose-group_replication_local_address= "127.0.0.1:24905"
    loose-group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903,127.0.0.1:24904,127.0.0.1:24905"
    loose-group_replication_bootstrap_group= off
    loose-group_replication_single_primary_mode=false
    loose-group_replication_enforce_update_everywhere_checks=true

启动s5

nohup mysql-5.7/bin/mysqld --defaults-file=data/s5/s5.cnf >data/s5/nohup.out 2>data/s5/nohup.out &

其他后续步骤省略，依据s4的部署执行即可。

最后也成功将s5加入GR集群:

## 2.4 后续操作 ##

到这里我们已经完成了s4和s5的动态添加，当然，为了下次s1、s2、s3重启后gr配置仍然能够生效，我们需要修改s1.cnf、s2.cnf和s3.cnf里面的一个配置项为:

loose-group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903,127.0.0.1:24904,127.0.0.1:24905"

这样能够确保下次重启这些节点，GR的配置能够是最新的配置。

[MySQL Group Replication _ _Multi-Primary Mode]: http://blog.csdn.net/d6619309/article/details/53691790
[MySQL Group Replication _ _Single-Primary Mode]: http://blog.csdn.net/d6619309/article/details/53786995