详细介绍：MySQL高可用集群

https://dev.mysql.com/doc/mysql-shell/8.4/en/mysql-innodb-cluster.html

1 什么是MySQL高可用集群

• MySQL高可用集群：MySQLInnoDBCluster
• InnoDBCluster是MySQL官方实现高可用+读写分离的架构方案，包含以下组件
  • MySQLGroupReplication：简称MGR，是MySQL的主从同步高可用方案，包括数据同步和角色选举
  • MySQLShell是InnoDBCluster的管理工具，用来创建和管理集群
  • MySQLRouter是业务流量入口，支持对MGR的主从角色判断，可以配置不同的端口分别对外提供读写服务，实现读写分离
• MySQLInnoDBCluster架构图

• InnoDBCluster将三个MySQL数据库实例构成一个高可用集群
• 其中一个实例是具有读写能力的主成员
• 其他两个实例是具有只读能力的次成员
• 组复制将数据从主成员复制到次成员
• MySQLRouter将连接读写端口的客户端请求转发到主成员，将连接到只读端口的客户端请求转发到次成员

2 搭建高可用集群示例

2.1 准备三个MySQL实例

2.2.1 准备MySQL实例20000

• 创建目录

mkdir -p /opt/mysql/20000/{data,log,tmp}

• 准备配置文件

vi /opt/mysql/20000/my.cnf[mysql]
#设置mysql客户端默认编码
default-character-set=utf8
[mysqld]
port=20000
pid-file= /opt/mysql/20000/mysqld.pid
socket= /opt/mysql/20000/mysqld.sock
datadir= /opt/mysql/20000/data
log-error=/opt/mysql/20000/log/mysqld.log
tmpdir=/opt/mysql/20000/tmp
mysqlx-port=20010
mysqlx-socket=/opt/mysql/20000/mysqldx.sock
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
#服务器唯一ID，默认是1
server-id=20000
#启用二进制日志
log-bin=mysql-bin
#最大连接数
max_connections=1000
#设置默认时区
default-time_zone='+8:00'
# 0:区分大小写
# 1:不区分大小写
lower_case_table_names=1
user = mysql
#启用全局事务标识符（GTID）模式
gtid_mode=on
#强制GTID的一致性。这意味着在执行事务时，MySQL将确保所有涉及的服务器都使用相同的GTID集。
enforce_gtid_consistency=on
#启用并行复制
binlog_transaction_dependency_tracking=WRITESET
replica_preserve_commit_order=ON
replica_parallel_type=LOGICAL_CLOCK
transaction_write_set_extraction=XXHASH64

• 初始化库

chown -R mysql:mysql /opt/mysql/20000
mysqld --defaults-file=/opt/mysql/20000/my.cnf --initialize

• 启库

mysqld --defaults-file=/opt/mysql/20000/my.cnf &

• 初始化密码

#查看临时密码
cat /opt/mysql/20000/log/mysqld.log|grep "A temporary password"
#登录
mysql -uroot -p'ji2m:aJ9K26y' --socket=/opt/mysql/20000/mysqld.sock
>ALTER USER 'root'@'localhost' identified by '123456';
CREATE USER 'root'@'%' IDENTIFIED BY '123456';
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%';
flush privileges;

• 给root账号赋InnoDB Cluster 相关权限

mysql -uroot -p'123456' --socket=/opt/mysql/20000/mysqld.sock
>
GRANT CLONE_ADMIN, CONNECTION_ADMIN, CREATE USER,
EXECUTE, FILE, GROUP_REPLICATION_ADMIN, PERSIST_RO_VARIABLES_ADMIN, PROCESS, RELOAD, REPLICATION CLIENT, REPLICATION SLAVE, REPLICATION_APPLIER, REPLICATION_SLAVE_ADMIN, ROLE_ADMIN, SELECT, SHUTDOWN, SYSTEM_VARIABLES_ADMIN ON *.* TO 'root'@'%' WITH GRANT OPTION;
GRANT DELETE,
INSERT,
UPDATE ON mysql.* TO 'root'@'%' WITH GRANT OPTION;
GRANT ALTER,
ALTER ROUTINE, CREATE,
CREATE ROUTINE, CREATE TEMPORARY TABLES, CREATE VIEW,
DELETE,
DROP, EVENT, EXECUTE, INDEX, INSERT, LOCK TABLES, REFERENCES,
SHOW VIEW,
TRIGGER,
UPDATE ON mysql_innodb_cluster_metadata.* TO 'root'@'%' WITH GRANT OPTION;
GRANT ALTER,
ALTER ROUTINE, CREATE,
CREATE ROUTINE, CREATE TEMPORARY TABLES, CREATE VIEW,
DELETE,
DROP, EVENT, EXECUTE, INDEX, INSERT, LOCK TABLES, REFERENCES,
SHOW VIEW,
TRIGGER,
UPDATE ON mysql_innodb_cluster_metadata_bkp.* TO 'root'@'%' WITH GRANT OPTION;
GRANT ALTER,
ALTER ROUTINE, CREATE,
CREATE ROUTINE, CREATE TEMPORARY TABLES, CREATE VIEW,
DELETE,
DROP, EVENT, EXECUTE, INDEX, INSERT, LOCK TABLES, REFERENCES,
SHOW VIEW,
TRIGGER,
UPDATE ON mysql_innodb_cluster_metadata_previous.* TO 'root'@'%' WITH GRANT OPTION;

2.2.2 复制实例20001

cp -rf /opt/mysql/20000 /opt/mysql/20001
sed -i "s#20000#20001#g" /opt/mysql/20001/my.cnf
sed -i "s#20010#20011#g" /opt/mysql/20001/my.cnf
rm -f /opt/mysql/20001/data/auto.cnf
chown -R mysql:mysql /opt/mysql/20001
mysqld --defaults-file=/opt/mysql/20001/my.cnf &

2.2.3 复制实例20002

cp -rf /opt/mysql/20000 /opt/mysql/20002
sed -i "s#20000#20002#g" /opt/mysql/20002/my.cnf
sed -i "s#20010#20012#g" /opt/mysql/20001/my.cnf
rm -f /opt/mysql/20002/data/auto.cnf
chown -R mysql:mysql /opt/mysql/20002
mysqld --defaults-file=/opt/mysql/20002/my.cnf &

2.2MySQL Shell部署集群

2.2.1 安装MySQL Shell

MySQL :: Download MySQL Shell

2.2.2 MySQL Shell 集群相关常用命令

mysqlsh root@192.168.221.100:20000 --js
> dba.help(); --查看帮助文档
? dba.deploySandboxInstance --查看具体操作的帮助文档

2.2.3 检测实例是否满足要求

mysqlsh root@192.168.221.100:20000 --js
> dba.checkInstanceConfiguration('root@192.168.221.100:20000');
dba.checkInstanceConfiguration('root@192.168.221.100:20001');
dba.checkInstanceConfiguration('root@192.168.221.100:20002');

返回ok表示验证通过

2.2.4 初始化InnoDB Cluster配置

mysqlsh root@192.168.221.100:20000 --js
> dba.configureInstance('root@192.168.221.100:20000');
dba.configureInstance('root@192.168.221.100:20001');
dba.configureInstance('root@192.168.221.100:20002');

2.2.5 使用主实例创建集群

• 创建集群

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.createCluster('myCluster');

• 创建集群后默认会将当前节点添加进集群，并作为主节点
• 默认创建单主模式集群

• 查看集群状态

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.status();

2.2.6 添加副本实例

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.addInstance('root@192.168.221.100:20001');
cluster.addInstance('root@192.168.221.100:20002');
cluster.status();

新添加进来的实例默认作为副本节点

2.3 InnoDB Cluster数据同步测试

• 主库20000添加数据

mysql -uroot -p'123456' --socket=/opt/mysql/20000/mysqld.sock
> create database test;
use test;
create table test (id int,name varchar(10));
ALTER TABLE test ADD PRIMARY KEY id(id);
insert into test values(1,
'a'),(2,
'b'),(3,
'c');

• 从库20001查询数据

mysql -uroot -p'123456' --socket=/opt/mysql/20001/mysqld.sock
>
use test;
select * from test;

• 从库20002查询数据

mysql -uroot -p'123456' --socket=/opt/mysql/20002/mysqld.sock
>
use test;
select * from test;

2.4 InnoDB Cluster主从切换测试

• kill主库实例20000
• 查看组成员

mysql -uroot -p'123456' --socket=/opt/mysql/20001/mysqld.sock
>
SELECT CHANNEL_NAME,MEMBER_ID,MEMBER_HOST,MEMBER_PORT, MEMBER_ROLE FROM performance_schema.replication_group_members;

• 查看集群状态

mysqlsh root@192.168.221.100:20001 --js
> var cluster = dba.getCluster('myCluster');
cluster.status();

2.5 MySQL Shell集群常见操作

2.5.1 参数配置

• 使用cluster.options()查看当前集群的配置属性
• 集群参数配置分为两种方式
  • cluster.setOption()设置集群属性，所有节点的
  • cluster.setInstanceOption()设置指定节点属性

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.setOption("memberWeight",
50);
#重新加入集群重试次数改为5次
cluster.setOption("autoRejoinTries",
5);#将其中一个节点的权重改为75
cluster.setInstanceOption("192.168.221.100:20001",
"memberWeight",
75)；
#重新加入集群重试次数改为10次
cluster.setInstanceOption("192.168.221.100:20001",
"autoRejoinTries",
10)

2.5.2 配置节点权重

• memberWeight选项的值域为0~100之间的整数，缺省值为50;
• 该值是故障转移时自动选举主节点的百分比权重
• 具有较高memberWeight值的实例更有可能在单主集群被选为主节点

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
#查看集群的参数配置
cluster.options();#创建集群配置
dba.createCluster('myCluster', {memberWeight:75});
#添加实例时配置
var cluster = dba.getCluster();
cluster.addInstance('root@192.168.221.100:20001',{memberWeight:50});
#集群创建完后修改配置
cluster.setInstanceOption('192.168.221.100:20000',
'memberWeight',
100)

2.5.3 将节点重新加入集群

• 状态为missing的节点是组复制关闭或者中断
• 可使用cluster.rejionInstance()重新加入集群
• 会重新对该节点设置MGR相关参数

2.5.4 集群多数节点异常恢复

• 当集群多个节点异常，则失去了仲裁机制，无法选举出主节点
• 使用cluster.forceQuorumUsingPartitionOf将集群剥离为单节点运行

2.5.5 集群节点角色切换

• 单主模式指定主节点切换

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.setPrimaryInstance('192.168.221.100:20001');

• 单主模式切换为多主模式

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.switchToMultiPrimaryMode();

• 多主模式切换为单主模式

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.switchToSinglePrimaryMode("192.168.221.100:20000")

2.5.6 销毁集群

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.dissolve();

2.5.7 创建集群管理用户

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.setupAdminAccount('test');

• 该操作会创建MySQL系统账号
• mysqlsh连接集群时也可使用该账号登录

2.6 MySQL Router连接集群

2.6.1 安装MySQL Router

MySQL :: Download MySQL Router

2.6.2 配置路由

mysqlrouter --bootstrap root@192.168.221.100:20000 --force --user=root

2.6.3 查看集群路由信息

mysqlsh root@192.168.221.100:20000 --js
> var cluster = dba.getCluster('myCluster');
cluster.listRouters();

2.6.4 启动路由

mysqlrouter &

2.6.5 通过路由连接MySQL

• mysqlclient连接路由

mysql -uroot -p123456 -P6446 -h192.168.221.100

• mysqlsh连接路由

mysqlsh root@192.168.221.100:6446 --sql

2.7 MySQL Router连接测试

• R/W端口测试读写
• R/O端口测试读写
• R/W Split端口测试读写