1. 节点信息

hostname	IP地址	mysql  MGR
mysql1	172.16.230.51
mysql2	172.16.230.52
mysql3	172.16.230.53

 

 

 

 

 

2. 三个节点安装mysql8 实例

 

3. 每个节点初始化mysql账号

create user 'fengjian'@'%' identified by '123456';
grant all on *.* to  'fengjian'@'%' with grant option;

 

4. 下载 mysql shell

[root@mysql1 ~]# wget https://cdn.mysql.com//Downloads/MySQL-Shell/mysql-shell-8.0.23-linux-glibc2.12-x86-64bit.tar.gz
[root@mysql1 ~]# tar -zxvf mysql-shell-8.0.23-linux-glibc2.12-x86-64bit.tar.gz
[root@mysql1 ~]# mv mysql-shell-8.0.23-linux-glibc2.12-x86-64bit /usr/local/mysqlshell
[root@mysql3 ~]# chown -R  mysql.mysql /usr/local/mysqlshell 

5. 拷贝mysqlshell 到其他节点

[root@mysql1 ~]#scp - /usr/local/mysqlshell  root@172.16.230.52:/usr/local/
[root@mysql2 ~]#chown -R  mysql.mysql /usr/local/mysqlshell 

[root@mysql1 ~]# scp - /usr/local/mysqlshell  root@172.16.230.52:/usr/local/
[root@mysql3 ~]# chown -R  mysql.mysql /usr/local/mysqlshell 

 

6. 利用mysql shell 构建MGR

[root@mysql1 ~]# /usr/local/mysqlshell/bin/mysqlsh

# 链接一个mysql节点
shell.connect('fengjian@172.16.230.51:3306')

#定义一个集群
var cluster = dba.createCluster('SenyintCluster')

# 其他节点实例加入到集群
cluster.addinstance('fengjian@172.16.230.52:3306')

 

 

cluster.addinstance('fengjian@172.16.230.53:3306')

#查看集群状态
cluster.status()



# 当链接超时需要 重新链接
MySQL  172.16.230.51:3306 ssl  JS > shell.connect('fengjian@172.16.230.51:3306')
#cluster 表示获取
var cluster = dba.getCluster('SenyintCluster')

 

报错信息:

 MySQL  172.16.230.51:3306 ssl  JS > var cluster=dba.createCluster('SenyintCluster')
A new InnoDB cluster will be created on instance '172.16.230.51:3306'.

Validating instance configuration at 172.16.230.51:3306...

This instance reports its own address as mysql1:3306

NOTE: Some configuration options need to be fixed:
+-----------------------------+---------------+----------------+----------------------------+
| Variable                    | Current Value | Required Value | Note                       |
+-----------------------------+---------------+----------------+----------------------------+
| slave_preserve_commit_order | OFF           | ON             | Update the server variable |
+-----------------------------+---------------+----------------+----------------------------+

NOTE: Please use the dba.configureInstance() command to repair these issues.

ERROR: Instance must be configured and validated with dba.checkInstanceConfiguration() and dba.configureInstance() before it can be used in an InnoDB cluster.
Dba.createCluster: Instance check failed (RuntimeError)

修复:
set global slave_preserve_commit_order = 1;

 

数据复制: 分两种情况

1.  正常复制通道 group_replication_applier 状态:   online 无延迟状态下复制

2.  延迟复制通道 group_replication_recovery 出现在复制延迟扬中, MGR 节点退化recovery 状态, SQL_Thread 从 relay_log中应用数据.

 

 

 

多主模式如何实现多点写入(multi-master)

1. 修改了每个节点的 auto_increment_offset, auto_increment_increment

2. 每个节点一个独立的GTID区间

3. 实现同一条数据, 同时一时间只能在一个节点上update, 同时下次修改必须保证前面的数据应用完毕

 MySQL  172.16.230.51:3306 ssl  JS > cluster.status()
{
    "clusterName": "SenyintCluster", 
    "defaultReplicaSet": {
        "name": "default", 
        "primary": "mysql1:3306", 
        "ssl": "REQUIRED", 
        "status": "OK", 
        "statusText": "Cluster is ONLINE and can tolerate up to ONE failure.", 
        "topology": {
            "mysql1:3306": {
                "address": "mysql1:3306", 
                "mode": "R/W", 
                "readReplicas": {}, 
                "replicationLag": null, 
                "role": "HA", 
                "status": "ONLINE", 
                "version": "8.0.22"
            }, 
            "mysql2:3306": {
                "address": "mysql2:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "replicationLag": null, 
                "role": "HA", 
                "status": "ONLINE", 
                "version": "8.0.22"
            }, 
            "mysql3:3306": {
                "address": "mysql3:3306", 
                "mode": "R/O", 
                "readReplicas": {}, 
                "replicationLag": null, 
                "role": "HA", 
                "status": "ONLINE", 
                "version": "8.0.22"
            }
        }, 
        "topologyMode": "Single-Primary"
    }, 
    "groupInformationSourceMember": "mysql1:3306"
}

 

mysql shell 切换成 multi-master 模式

 MySQL  172.16.230.51:3306 ssl  JS > cluster.switchToMultiPrimaryMode()
Switching cluster 'SenyintCluster' to Multi-Primary mode...

Instance 'mysql1:3306' remains PRIMARY.
Instance 'mysql2:3306' was switched from SECONDARY to PRIMARY.
Instance 'mysql3:3306' was switched from SECONDARY to PRIMARY.

The cluster successfully switched to Multi-Primary mode.