摘要：本文分享一下“MHA+中间件ProxySQL”如何来实现读写分离+负载均衡的相关知识。
本文分享自华为云社区《MySQL高可用架构MHA+ProxySQL实现读写分离和负载均衡》，作者：小麦苗DB宝。
一、MHA+ProxySQL架构
我们都知道，MHA（Master High Availability Manager and tools for MySQL）目前在MySQL高可用方面是一个相对成熟的解决方案，是一套作为MySQL高可用性环境下故障切换和主从提升的高可用软件。它的架构是要求一个MySQL复制集群必须最少有3台数据库服务器，一主二从，即一台充当Master，一台充当备用Master，另一台充当从库。但是，如果不连接任何外部的数据库中间件，那么就会导致所有的业务压力流向主库，从而造成主库压力过大，而2个从库除了本身的IO和SQL线程外，无任何业务压力，会严重造成资源的浪费。因此，我们可以把MHA和ProxySQL结合使用来实现读写分离和负载均衡。所有的业务通过中间件ProxySQL后，会被分配到不同的MySQL机器上。从而，前端的写操作会流向主库，而读操作会被负载均衡的转发到2个从库上。
MHA+ProxySQL架构如下图所示：
https://cdn.jsdelivr.net/gh/lhrbest/pic/img/20210416111756.png
二、快速搭建MHA环境
2.1 下载MHA镜像
- 小麦苗的Docker Hub的地址：https://hub.docker.com/u/lhrbest
-- 下载镜像
docker pull registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-master1-ip131 docker pull registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-slave1-ip132 docker pull registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-slave2-ip133 docker pull registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-monitor-ip134
-- 重命名镜像
docker tag registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-master1-ip131 lhrbest/mha-lhr-master1-ip131 docker tag registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-slave1-ip132 lhrbest/mha-lhr-slave1-ip132 docker tag registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-slave2-ip133 lhrbest/mha-lhr-slave2-ip133 docker tag registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-monitor-ip134 lhrbest/mha-lhr-monitor-ip134
一共4个镜像，3个MHA Node，一个MHA Manager，压缩包大概3G，下载完成后：
[root@lhrdocker ~]# docker images | grep mha registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-monitor-ip134 latest 7d29597dc997 14 hours ago 1.53GB registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-slave2-ip133 latest d3717794e93a 40 hours ago 4.56GB registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-slave1-ip132 latest f62ee813e487 40 hours ago 4.56GB registry.cn-hangzhou.aliyuncs.com/lhrbest/mha-lhr-master1-ip131 latest ae7be48d83dc 40 hours ago 4.56GB
2.2 编辑yml文件，创建MHA相关容器
编辑yml文件，使用docker-compose来创建MHA相关容器，注意docker-compose.yml文件的格式，对空格、缩进、对齐都有严格要求：
# 创建存放yml文件的路径 mkdir -p /root/mha # 编辑文件/root/mha/docker-compose.yml cat > /root/mha/docker-compose.yml <<"EOF" version: '3.8' services: MHA-LHR-Master1-ip131: container_name: "MHA-LHR-Master1-ip131" restart: "always" hostname: MHA-LHR-Master1-ip131 privileged: true image: lhrbest/mha-lhr-master1-ip131 ports: - "33131:3306" - "2201:22" networks: mhalhr: ipv4_address: 192.168.68.131 MHA-LHR-Slave1-ip132: container_name: "MHA-LHR-Slave1-ip132" restart: "always" hostname: MHA-LHR-Slave1-ip132 privileged: true image: lhrbest/mha-lhr-slave1-ip132 ports: - "33132:3306" - "2202:22" networks: mhalhr: ipv4_address: 192.168.68.132 MHA-LHR-Slave2-ip133: container_name: "MHA-LHR-Slave2-ip133" restart: "always" hostname: MHA-LHR-Slave2-ip133 privileged: true image: lhrbest/mha-lhr-slave2-ip133 ports: - "33133:3306" - "2203:22" networks: mhalhr: ipv4_address: 192.168.68.133 MHA-LHR-Monitor-ip134: container_name: "MHA-LHR-Monitor-ip134" restart: "always" hostname: MHA-LHR-Monitor-ip134 privileged: true image: lhrbest/mha-lhr-monitor-ip134 ports: - "33134:3306" - "2204:22" networks: mhalhr: ipv4_address: 192.168.68.134 networks: mhalhr: name: mhalhr ipam: config: - subnet: "192.168.68.0/16" EOF
2.3 安装docker-compose软件（若已安装，可忽略）
-
安装 Docker Compose官方文档：https://docs.docker.com/compose/
-
编辑docker-compose.yml文件官方文档：https://docs.docker.com/compose/compose-file/
[root@lhrdocker ~]# curl --insecure -L https://github.com/docker/compose/releases/download/1.28.4/docker-compose-Linux-x86_64 -o /usr/local/bin/docker-compose % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 638 100 638 0 0 530 0 0:00:01 0:00:01 --:--:-- 531 100 11.6M 100 11.6M 0 0 1994k 0 0:00:06 0:00:06 --:--:-- 2943k [root@lhrdocker ~]# chmod +x /usr/local/bin/docker-compose [root@lhrdocker ~]# docker-compose -v docker-compose version 1.28.4, build cabd5cfb
2.4 创建MHA容器
# 启动mha环境的容器，一定要进入文件夹/root/mha/后再操作 -- docker rm -f MHA-LHR-Master1-ip131 MHA-LHR-Slave1-ip132 MHA-LHR-Slave2-ip133 MHA-LHR-Monitor-ip134 [root@lhrdocker ~]# cd /root/mha/ [root@lhrdocker mha]# [root@lhrdocker mha]# docker-compose up -d Creating network "mhalhr" with the default driver Creating MHA-LHR-Monitor-ip134 ... done Creating MHA-LHR-Slave2-ip133 ... done Creating MHA-LHR-Master1-ip131 ... done Creating MHA-LHR-Slave1-ip132 ... done [root@docker35 ~]# docker ps | grep "mha\|COMMAND" CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 2978361198b7 lhrbest/mha-lhr-master1-ip131 "/usr/sbin/init" 2 minutes ago Up 2 minutes 16500-16599/tcp, 0.0.0.0:2201->22/tcp, 0.0.0.0:33131->3306/tcp MHA-LHR-Master1-ip131 a64e2e86589c lhrbest/mha-lhr-slave1-ip132 "/usr/sbin/init" 2 minutes ago Up 2 minutes 16500-16599/tcp, 0.0.0.0:2202->22/tcp, 0.0.0.0:33132->3306/tcp MHA-LHR-Slave1-ip132 d7d6ce34800b lhrbest/mha-lhr-monitor-ip134 "/usr/sbin/init" 2 minutes ago Up 2 minutes 0.0.0.0:2204->22/tcp, 0.0.0.0:33134->3306/tcp MHA-LHR-Monitor-ip134 dacd22edb2f8 lhrbest/mha-lhr-slave2-ip133 "/usr/sbin/init" 2 minutes ago Up 2 minutes 16500-16599/tcp, 0.0.0.0:2203->22/tcp, 0.0.0.0:33133->3306/tcp MHA-LHR-Slave2-ip133
2.5 主库131添加VIP
# 进入主库131 docker exec -it MHA-LHR-Master1-ip131 bash # 添加VIP135 /sbin/ifconfig eth0:1 192.168.68.135/24 ifconfig # 如果删除的话 ip addr del 192.168.68.135/24 dev eth1
添加完成后：
[root@MHA-LHR-Master1-ip131 /]# ifconfig eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.68.131 netmask 255.255.0.0 broadcast 192.168.255.255 ether 02:42:c0:a8:44:83 txqueuelen 0 (Ethernet) RX packets 220 bytes 15883 (15.5 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 189 bytes 17524 (17.1 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.68.135 netmask 255.255.255.0 broadcast 192.168.68.255 ether 02:42:c0:a8:44:83 txqueuelen 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 loop txqueuelen 1000 (Local Loopback) RX packets 5 bytes 400 (400.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 5 bytes 400 (400.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 # 管理节点已经可以ping通VIP了 [root@MHA-LHR-Monitor-ip134 /]# ping 192.168.68.135 PING 192.168.68.135 (192.168.68.135) 56(84) bytes of data. 64 bytes from 192.168.68.135: icmp_seq=1 ttl=64 time=0.172 ms 64 bytes from 192.168.68.135: icmp_seq=2 ttl=64 time=0.076 ms ^C --- 192.168.68.135 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1000ms rtt min/avg/max/mdev = 0.076/0.124/0.172/0.048 ms
到这一步就可以验证主从复制是否正确，若正确，则可以直接测试MHA了。
mysql -uroot -plhr -h192.168.68.131 -P3306 show slave hosts; mysql> show slave hosts; +-----------+----------------+------+-----------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +-----------+----------------+------+-----------+--------------------------------------+ | 573306133 | 192.168.68.133 | 3306 | 573306131 | d391ce7e-aec3-11ea-94cd-0242c0a84485 | | 573306132 | 192.168.68.132 | 3306 | 573306131 | d24a77d1-aec3-11ea-9399-0242c0a84484 | +-----------+----------------+------+-----------+--------------------------------------+ 2 rows in set (0.00 sec)
https://cdn.jsdelivr.net/gh/lhrbest/pic/img/20210416111806.png
三、配置ProxySQL环境
3.1 申请ProxySQL主机并安装ProxySQL
docker rm -f MHA-LHR-ProxySQL-ip136 docker run -d --name MHA-LHR-ProxySQL-ip136 -h MHA-LHR-ProxySQL-ip136 \ -v /sys/fs/cgroup:/sys/fs/cgroup \ --network mhalhr --ip 192.168.68.136 \ -p 26032:6032 -p 26033:6033 -p 26080:6080 \ --privileged=true lhrbest/lhrcentos76:8.0 \ /usr/sbin/init docker network connect bridge MHA-LHR-ProxySQL-ip136 docker restart MHA-LHR-ProxySQL-ip136 docker cp proxysql2-2.0.15-1.1.el7.x86_64.rpm MHA-LHR-ProxySQL-ip136:/ docker exec -it MHA-LHR-ProxySQL-ip136 bash rpm -ivh proxysql2-2.0.15-1.1.el7.x86_64.rpm systemctl start proxysql systemctl status proxysql
3.2 添加远程登录用户
-- 添加远程登录用户 mysql -uadmin -padmin -h127.0.0.1 -P6032 select @@admin-admin_credentials; set admin-admin_credentials='admin:admin;root:lhr'; select @@admin-admin_credentials; load admin variables to runtime; save admin variables to disk; -- 远程登录 mysql -uroot -plhr -h192.168.66.35 -P26032
执行过程：
-- ProxySQL本地登录 [root@MHA-LHR-ProxySQL-ip136 /]# mysql -uadmin -padmin -h127.0.0.1 -P6032 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 162 Server version: 5.5.30 (ProxySQL Admin Module) Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> select @@admin-admin_credentials; +---------------------------+ | @@admin-admin_credentials | +---------------------------+ | admin:admin;lhr:lhr | +---------------------------+ 1 row in set (0.05 sec) mysql> set admin-admin_credentials='admin:admin;root:lhr'; Query OK, 1 row affected (0.00 sec) mysql> select @@admin-admin_credentials; +---------------------------+ | @@admin-admin_credentials | +---------------------------+ | admin:admin;root:lhr | +---------------------------+ 1 row in set (0.00 sec) mysql> load admin variables to runtime; Query OK, 0 rows affected (0.00 sec) mysql> save admin variables to disk; Query OK, 35 rows affected (0.13 sec) mysql> -- 远程登录 C:\Users\lhrxxt>mysql -uroot -plhr -h192.168.66.35 -P26032 mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 1045 (28000): ProxySQL Error: Access denied for user 'root'@'172.17.0.1' (using password: YES) C:\Users\lhrxxt>mysql -uroot -plhr -h192.168.66.35 -P26032 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 163 Server version: 5.5.30 (ProxySQL Admin Module) Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MySQL [(none)]> show databases; +-----+---------------+-------------------------------------+ | seq | name | file | +-----+---------------+-------------------------------------+ | 0 | main | | | 2 | disk | /var/lib/proxysql/proxysql.db | | 3 | stats | | | 4 | monitor | | | 5 | stats_history | /var/lib/proxysql/proxysql_stats.db | +-----+---------------+-------------------------------------+ 5 rows in set (0.05 sec)
3.3 开启ProxySQL的web监控功能
-- 开启web监控功能 SET admin-web_enabled='true'; LOAD ADMIN VARIABLES TO RUNTIME; SAVE ADMIN VARIABLES TO DISK; select * from global_variables where variable_name LIKE 'admin-web_enabled'; select @@admin-web_enabled; lsof -i:6080 -- 浏览器访问 https://192.168.66.35:26080 用户名和密码：stats:stats
https://cdn.jsdelivr.net/gh/lhrbest/pic/img/20210416111815.png
3.4 配置被监控的数据库
3.4.1 向ProxySQL插入被监控数据库
-- 1、向ProxySQL插入被监控数据库 select * from mysql_servers; insert into main.mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.68.131',3306); insert into main.mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.68.132',3306); insert into main.mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.68.133',3306); load mysql servers to runtime; save mysql servers to disk; select * from mysql_servers; MySQL [(none)]> select * from mysql_servers; +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.68.131 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 10 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 10 | 192.168.68.133 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.07 sec)
3.4.2 在所有被监控MySQL服务器上创建监控帐户
-- 2、在所有被监控MySQL服务器上创建帐户，注意：新版本中，这里的密码必须为monitor，可参考配置文件/etc/proxysql.cnf mysql -uroot -plhr -h192.168.66.35 -P33131 create user 'monitor'@'%' IDENTIFIED BY 'monitor'; GRANT all privileges ON *.* TO 'monitor'@'%' with grant option; select user,host from mysql.user; mysql> select user,host from mysql.user; +---------------+--------------+ | user | host | +---------------+--------------+ | mha | % | | monitor | % | | repl | % | | root | % | | mysql.session | localhost | | mysql.sys | localhost | | root | localhost | +---------------+--------------+ 7 rows in set (0.00 sec)
3.4.3 在所有被监控MySQL服务器上创建对外访问账户
-- 3、 在所有被监控MySQL服务器上创建对外访问账户： create user 'wr'@'%' IDENTIFIED BY 'lhr'; GRANT all privileges ON *.* TO 'wr'@'%' with grant option; -- 配置到ProxySQL中 insert into mysql_users(username,password,default_hostgroup) values('wr','lhr',10); update mysql_users set transaction_persistent=1 where username='wr'; load mysql users to runtime; save mysql users to disk; select * from mysql_users; MySQL [(none)]> select * from mysql_users; +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+ | username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | comment | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+ | wr | lhr | 1 | 0 | 10 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 | | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+---------+ 1 row in set (0.05 sec)
3.4.4 配置监控
-- 4、在ProxySQL端执行下列SQL语句： set mysql-monitor_username='monitor'; set mysql-monitor_password='monitor'; load mysql servers to runtime; save mysql servers to disk; select * from global_variables where variable_name in('mysql-monitor_username','mysql-monitor_password'); +------------------------+----------------+ | variable_name | variable_value | +------------------------+----------------+ | mysql-monitor_password | monitor | | mysql-monitor_username | monitor | +------------------------+----------------+ 2 rows in set (0.05 sec) -- 检查连接到MySQL的日志 select * from monitor.mysql_server_ping_log order by time_start_us desc limit 6; select * from monitor.mysql_server_connect_log order by time_start_us desc limit 6; MySQL [(none)]> select * from monitor.mysql_server_ping_log order by time_start_us desc limit 6; +----------------+------+------------------+----------------------+------------+ | hostname | port | time_start_us | ping_success_time_us | ping_error | +----------------+------+------------------+----------------------+------------+ | 192.168.68.132 | 3306 | 1614050308827202 | 252 | NULL | | 192.168.68.133 | 3306 | 1614050308716530 | 370 | NULL | | 192.168.68.131 | 3306 | 1614050308605853 | 542 | NULL | | 192.168.68.131 | 3306 | 1614050298778908 | 334 | NULL | | 192.168.68.133 | 3306 | 1614050298690947 | 297 | NULL | | 192.168.68.132 | 3306 | 1614050298605725 | 344 | NULL | +----------------+------+------------------+----------------------+------------+ 6 rows in set (0.06 sec) MySQL [(none)]> select * from monitor.mysql_server_connect_log order by time_start_us desc limit 6; +----------------+------+------------------+-------------------------+---------------+ | hostname | port | time_start_us | connect_success_time_us | connect_error | +----------------+------+------------------+-------------------------+---------------+ | 192.168.68.131 | 3306 | 1614050285481316 | 1173 | NULL | | 192.168.68.133 | 3306 | 1614050284894846 | 1008 | NULL | | 192.168.68.132 | 3306 | 1614050284309124 | 970 | NULL | | 192.168.68.131 | 3306 | 1614050225194575 | 1108 | NULL | | 192.168.68.133 | 3306 | 1614050224751771 | 987 | NULL | | 192.168.68.132 | 3306 | 1614050224309026 | 1294 | NULL | +----------------+------+------------------+-------------------------+---------------+ 6 rows in set (0.05 sec)
四、故障切换
在Manager节点检查SSH、复制及MHA的状态。
docker exec -it MHA-LHR-Monitor-ip134 bash masterha_check_ssh --conf=/etc/mha/mha.cnf masterha_check_repl --conf=/etc/mha/mha.cnf masterha_check_status --conf=/etc/mha/mha.cnf -- 启动MHA监控进程 nohup masterha_manager --conf=/etc/mha/mha.cnf --ignore_last_failover < /dev/null > /usr/local/mha/manager_start.log 2>&1 & --关闭MHA监控进程 masterha_stop --conf=/etc/mha/mha.cnf [root@MHA-LHR-Monitor-ip134 /]# masterha_check_status --conf=/etc/mha/mha.cnf mha (pid:3738) is running(0:PING_OK), master:192.168.68.131
接下来，宕掉主库，继续观察ProxySQL的情况：
-- 宕掉主库
docker stop MHA-LHR-Master1-ip131
MHA自动执行了故障转移，主库切换为132，并发送告警邮件：
https://cdn.jsdelivr.net/gh/lhrbest/pic/img/20210416111828.png
此时，来查看ProxySQL的情况：
MySQL [(none)]> select * from mysql_servers; +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.131 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.133 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 4 rows in set (0.05 sec) MySQL [(none)]> select * from runtime_mysql_servers; +--------------+----------------+------+-----------+---------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+-----------+---------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.131 | 3306 | 0 | SHUNNED | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.133 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+-----------+---------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 4 rows in set (1.26 sec)
可以发现131已经变成SHUNNED状态，ProxySQL会避开这个主机。
此时再做压测等操作，所有负载会被分配到132和133上，此处不再测试。
接下来启动131，并以从库的身份加入原主从环境：
-- 启动131 docker start MHA-LHR-Master1-ip131 -- 在134的日志文件中找到恢复的语句 grep "All other slaves should start replication from here" /usr/local/mha/manager_running.log -- 在131上执行恢复 mysql -uroot -plhr -h192.168.68.131 -P3306 CHANGE MASTER TO MASTER_HOST='192.168.68.132', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='lhr'; start slave; show slave status \G -- 设置只读 set global read_only=1;
查询ProxySQL：
MySQL [(none)]> select * from mysql_servers; +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.131 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.133 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 4 rows in set (0.06 sec)
可以看到131为只读。若想让132只写，则可以删除相关记录：
MySQL [(none)]> delete from mysql_servers where hostgroup_id=20 and hostname='192.168.68.132'; Query OK, 1 row affected (0.06 sec) MySQL [(none)]> load mysql servers to runtime; Query OK, 0 rows affected (0.68 sec) MySQL [(none)]> save mysql servers to disk; Query OK, 0 rows affected (0.10 sec) MySQL [(none)]> select * from mysql_servers; +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.131 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.133 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.05 sec) MySQL [(none)]> select * from runtime_mysql_servers; +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.68.132 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.133 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 20 | 192.168.68.131 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.94 sec)
可以看到132为主库，131和133为从库。Orchestrator界面：
https://cdn.jsdelivr.net/gh/lhrbest/pic/img/20210416111835.png