准备环境

资源有限只需要准备一台Linux主机
腾讯云主机159.75.158.18

（1）规划部署

（2）准备实例配置文件
编辑3个配置文件，分别是
my3381.cnf
my3382.cnf
my3383.cnf

配置文件内容以my3383.cnf为例
将其中对应的数字3383 改为对应端口到不同配置文件

[mysqld] log_timestamps=SYSTEM user=mysql basedir=/usr/local/mysql8 datadir=/data/3383/data log_bin=/data/3383/binlog/mysql-bin port=3383 server_id=20243383 socket=/tmp/mysql3383.sock gtid-mode=on enforce-gtid-consistency=true log_slave_updates=1 relay_log_info_repository=TABLE master_info_repository=TABLE relay_log_recovery=on 

（3）创建目录

mkdir -p /data/3381/data mkdir -p /data/3381/binlog mkdir -p /data/3382/data mkdir -p /data/3382/binlog mkdir -p /data/3383/data mkdir -p /data/3383/binlog chown mysql.mysql -R /data 

（4）初始化和启动库

/usr/local/mysql8/bin/mysqld --defaults-file=/etc/my3381.cnf --basedir=/usr/local/mysql8 --initialize-insecure --datadir=/data/3381/data --user=mysql &  /usr/local/mysql8/bin/mysqld --defaults-file=/etc/my3382.cnf --basedir=/usr/local/mysql8 --initialize-insecure --datadir=/data/3382/data --user=mysql &  /usr/local/mysql8/bin/mysqld --defaults-file=/etc/my3383.cnf --basedir=/usr/local/mysql8 --initialize-insecure --datadir=/data/3383/data --user=mysql &    /usr/local/mysql8/bin/mysqld_safe --defaults-file=/etc/my3381.cnf --user=mysql &  /usr/local/mysql8/bin/mysqld_safe --defaults-file=/etc/my3382.cnf --user=mysql &  /usr/local/mysql8/bin/mysqld_safe --defaults-file=/etc/my3383.cnf --user=mysql & 

（5）创建账号

为了简化步骤，直接执行

三个库都执行  mysql> create user admin@'%' identified by 'admin'; Query OK, 0 rows affected (0.02 sec)  mysql> grant all on *.* to admin@'%' with grant option; Query OK, 0 rows affected (0.01 sec) 

此步骤不规范，正常操作应当是
Create a new admin account for InnoDB cluster with minimal required grants

#在本地通过socket方式登入
$ mysqlsh -S /data/****/mysql.sock root@localhost

执行
dba.configureInstance()

选择
2) Create a new admin account for InnoDB cluster with minimal required grants

数据用户和密码

在使用
mysqlsh --uri 用户@IP:端口 进入mysql shell界面

搭建MySQL shell环境

（1）下载：
https://dev.mysql.com/downloads/shell/

下载的shell版本和数据库版本保持一致

（2）解压
tar -zxvf mysql-shell-8.0.25-linux-glibc2.12-x86-64bit.tar.gz -C /opt/idc/mysql-shell8.0.25

（3）配置环境变量
vi /etc/profile
export PATH=/opt/idc/mysql-shell8.0.25/bin:$PATH
source /etc/profile

使用shell搭建MGR

(1)检查是否适配MGR节点
dba.checkInstanceConfiguration(‘admin@159.75.158.18:3381’)

MySQL  JS > dba.checkInstanceConfiguration('admin@159.75.158.18:3381') Validating MySQL instance at VM-20-8-centos:3381 for use in an InnoDB cluster...  This instance reports its own address as VM-20-8-centos:3381 Clients and other cluster members will communicate with it through this address by default. If this is not correct, the report_host MySQL system variable should be changed.  Checking whether existing tables comply with Group Replication requirements... No incompatible tables detected  Checking instance configuration... Instance configuration is compatible with InnoDB cluster  The instance 'VM-20-8-centos:3381' is valid to be used in an InnoDB cluster.  {     "status": "ok" } 

另外两台节点需要做此操作
dba.checkInstanceConfiguration(‘admin@159.75.158.18:3382’)
dba.checkInstanceConfiguration(‘admin@159.75.158.18:3383’)

如果此步报错说不符合MGR节点要求，执行第二步

（2）
执行 dba.configureInstance() 命令开始检查当前实例是否满足安装MGR集群的条件，如果不满足可以直接配置成为MGR集群的一个节点：

dba.configureInstance(‘admin@159.75.158.18:3381’)

dba.configureInstance('admin@159.75.158.18:3381') Configuring MySQL instance at VM-20-8-centos:3381 for use in an InnoDB cluster...  This instance reports its own address as VM-20-8-centos:3381 Clients and other cluster members will communicate with it through this address by default. If this is not correct, the report_host MySQL system variable should be changed.  applierWorkerThreads will be set to the default value of 4.  The instance 'VM-20-8-centos:3381' is valid to be used in an InnoDB cluster. The instance 'VM-20-8-centos:3381' is already ready to be used in an InnoDB cluster.  Successfully enabled parallel appliers. 

根据需要选择YES，后再返回执行第一个，看结果是否是OK

另外两个节点同样执行相同步骤
dba.configureInstance(‘admin@159.75.158.18:3382’)
dba.configureInstance(‘admin@159.75.158.18:3383’)

（3）连接主节点
MySQL JS > \connect admin@159.75.158.18:3381

（4）创建集群
dba.createCluster(‘mgrCluster’)
var cluster = dba.getCluster()

（5）添加节点
这里要指定MGR专用账号，我们用的是测试账户不符合规范
cluster.addInstance(‘admin@159.75.158.18:3382’)
cluster.addInstance(‘admin@159.75.158.18:3383’)

（6）查看集群状态

cluster.status()

查看集群状态   MySQL  159.75.158.18:3381 ssl  JS > cluster.status()   {     "clusterName": "mgrCluster",      "defaultReplicaSet": {         "name": "default",          "primary": "VM-20-8-centos:3381",          "ssl": "REQUIRED",          "status": "OK",          "statusText": "Cluster is ONLINE and can tolerate up to ONE failure.",          "topology": {             "VM-20-8-centos:3381": {                 "address": "VM-20-8-centos:3381",                  "memberRole": "PRIMARY",                  "mode": "R/W",                  "readReplicas": {},                  "replicationLag": null,                  "role": "HA",                  "status": "ONLINE",                  "version": "8.0.25"             },              "VM-20-8-centos:3382": {                 "address": "VM-20-8-centos:3382",                  "memberRole": "SECONDARY",                  "mode": "R/O",                  "readReplicas": {},                  "replicationLag": null,                  "role": "HA",                  "status": "ONLINE",                  "version": "8.0.25"             },              "VM-20-8-centos:3383": {                 "address": "VM-20-8-centos:3383",                  "memberRole": "SECONDARY",                  "mode": "R/O",                  "readReplicas": {},                  "replicationLag": null,                  "role": "HA",                  "status": "ONLINE",                  "version": "8.0.25"             }         },          "topologyMode": "Single-Primary"     },      "groupInformationSourceMember": "VM-20-8-centos:3381" } 

R/O是只读，R/W是读写，PRIMARY是主节点。

补充

切换到多主模式
cluster.switchToMultiPrimaryMode()

切换到单主模式
cluster.switchToSinglePrimaryMode(‘159.75.158.18:3381’)