MHA+ProxySQL实现读写分离高可用
最近在研究ProxySQL，觉得还挺不错的，所以就简单的折腾了一下，ProxySQL目前也是Percona在推荐的一个读写分离的中间件。关于详细的介绍可以参考官方文档。https://github.com/sysown/proxysql/wiki
本文主要介绍的是MHA+ProxySQL读写分离以及高可用，ProxySQL的细节请参考文档，目前已经有人写的非常详细了，文章最后会给出链接。当然和Group Replication，PXC搭配那是更完美的。关于MHA的配置参考我前面的文章，本文就不再介绍。下面来看看
MHA和ProxySQL搭配使用的架构图：
测试环境（1主2从）：
M-> 192.168.0.20 S1-> 192.168.0.30 S2-> 192.168.0.40 proxysql -> 192.168.0.10
1. 检查主从复制是否正常：
[root@db_server_yayun_04 ~]# masterha_check_repl --conf=/data/mha/3306/mha.cnf Thu Jun 15 17:45:32 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Thu Jun 15 17:45:32 2017 - [info] Reading application default configuration from /data/mha/3306/mha.cnf.. Thu Jun 15 17:45:32 2017 - [info] Updating application default configuration from /usr/local/bin/load_cnf.. Thu Jun 15 17:45:32 2017 - [info] Reading server configuration from /data/mha/3306/mha.cnf.. Thu Jun 15 17:45:32 2017 - [info] Setting max_ping_errors to 10, ping_interval to 3. Thu Jun 15 17:45:32 2017 - [info] MHA::MasterMonitor version 0.57. Thu Jun 15 17:45:32 2017 - [info] GTID failover mode = 1 Thu Jun 15 17:45:32 2017 - [info] Dead Servers: Thu Jun 15 17:45:32 2017 - [info] Alive Servers: Thu Jun 15 17:45:32 2017 - [info] 192.168.0.20(192.168.0.20:3306) Thu Jun 15 17:45:32 2017 - [info] 192.168.0.30(192.168.0.30:3306) Thu Jun 15 17:45:32 2017 - [info] 192.168.0.40(192.168.0.40:3306) Thu Jun 15 17:45:32 2017 - [info] Alive Slaves: Thu Jun 15 17:45:32 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Thu Jun 15 17:45:32 2017 - [info] GTID ON Thu Jun 15 17:45:32 2017 - [info] Replicating from 192.168.0.20(192.168.0.20:3306) Thu Jun 15 17:45:32 2017 - [info] Primary candidate for the new Master (candidate_master is set) Thu Jun 15 17:45:32 2017 - [info] 192.168.0.40(192.168.0.40:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Thu Jun 15 17:45:32 2017 - [info] GTID ON Thu Jun 15 17:45:32 2017 - [info] Replicating from 192.168.0.20(192.168.0.20:3306) Thu Jun 15 17:45:32 2017 - [info] Primary candidate for the new Master (candidate_master is set) Thu Jun 15 17:45:32 2017 - [info] Current Alive Master: 192.168.0.20(192.168.0.20:3306) Thu Jun 15 17:45:32 2017 - [info] Checking slave configurations.. Thu Jun 15 17:45:32 2017 - [info] Checking replication filtering settings.. Thu Jun 15 17:45:32 2017 - [info] binlog_do_db= , binlog_ignore_db= Thu Jun 15 17:45:32 2017 - [info] Replication filtering check ok. Thu Jun 15 17:45:32 2017 - [info] GTID (with auto-pos) is supported. Skipping all SSH and Node package checking. Thu Jun 15 17:45:32 2017 - [info] Checking SSH publickey authentication settings on the current master.. Thu Jun 15 17:45:33 2017 - [info] HealthCheck: SSH to 192.168.0.20 is reachable. Thu Jun 15 17:45:33 2017 - [info] 192.168.0.20(192.168.0.20:3306) (current master) +--192.168.0.30(192.168.0.30:3306) +--192.168.0.40(192.168.0.40:3306) Thu Jun 15 17:45:33 2017 - [info] Checking replication health on 192.168.0.30.. Thu Jun 15 17:45:33 2017 - [info] ok. Thu Jun 15 17:45:33 2017 - [info] Checking replication health on 192.168.0.40.. Thu Jun 15 17:45:33 2017 - [info] ok. Thu Jun 15 17:45:33 2017 - [warning] master_ip_failover_script is not defined. Thu Jun 15 17:45:33 2017 - [warning] shutdown_script is not defined. Thu Jun 15 17:45:33 2017 - [info] Got exit code 0 (Not master dead). MySQL Replication Health is OK. [root@db_server_yayun_04 ~]#
2. 配置后端MySQL。登入ProxySQL，把MySQL主从的信息添加进去。将主库master也就是做写入的节点放到HG 100中，salve节点做读放到HG 1000。在proxysql输入命令：
mysql -uadmin -padmin -h127.0.0.1 -P6032
[admin@127.0.0.1][(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(100,'192.168.0.20',3306,1,1000,10,'test my proxysql'); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(1000,'192.168.0.30',3306,1,1000,10,'test my proxysql'); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(1000,'192.168.0.40',3306,1,1000,10,'test my proxysql'); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> select * from mysql_servers; +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | 100 | 192.168.0.20 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test my proxysql | | 1000 | 192.168.0.30 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test my proxysql | | 1000 | 192.168.0.40 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test my proxysql | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ 3 rows in set (0.00 sec)
3. 配置后端MySQL用户。这个用户需要先在后端MySQL(20,30,40)里真实存在，一个是监控账号、一个是程序账号。
(1) 监控账号（用来监控后端mysql是否存活以及read_only变量）：
GRANT SUPER, REPLICATION CLIENT ON *.* TO 'proxysql'@'192.168.0.10' IDENTIFIED BY 'proxysql';
(2) 程序账号（这里为了后面测试方便给了all权限）：
GRANT all ON *.* TO 'yayun'@'192.168.0.10' identified by 'yayun';
4. 在后端MySQL里添加完之后再配置ProxySQL：这里需要注意，default_hostgroup需要和上面的对应。（proxysql）
[admin@127.0.0.1][(none)]> insert into mysql_users(username,password,active,default_hostgroup,transaction_persistent) values('yayun','yayun',1,100,1); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> select * from mysql_users; +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ | username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ | yayun | yayun | 1 | 0 | 100 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ 1 row in set (0.00 sec) [admin@127.0.0.1][(none)]>
5. 设置健康监测账号（proxysql）：
[admin@127.0.0.1][(none)]> set mysql-monitor_username='proxysql'; Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> set mysql-monitor_password='proxysql'; Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]>
6. 加载配置和变量：因为修改了servers、users和variables，所以加载的时候要执行：
[admin@127.0.0.1][(none)]> load mysql servers to runtime; Query OK, 0 rows affected (0.01 sec) [admin@127.0.0.1][(none)]> load mysql users to runtime; Query OK, 0 rows affected (0.00 sec) [admin@127.0.0.1][(none)]> load mysql variables to runtime; Query OK, 0 rows affected (0.00 sec) [admin@127.0.0.1][(none)]> save mysql servers to disk; Query OK, 0 rows affected (0.05 sec) [admin@127.0.0.1][(none)]> save mysql users to disk; Query OK, 0 rows affected (0.02 sec) [admin@127.0.0.1][(none)]> save mysql variables to disk; Query OK, 74 rows affected (0.01 sec) [admin@127.0.0.1][(none)]>
7. 连接数据库，通过proxysql的客户端接口访问(6033)：(我这里从40从库上面发起连接)
mysql -uyayun -pyayun -h192.168.0.10 -P6033
[root@db_server_yayun_04 ~]# mysql -uyayun -pyayun -h192.168.0.10 -P6033 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 4 Server version: 5.5.30 (ProxySQL) Copyright (c) 2000, 2016, 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. [yayun@192.168.0.10][(none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | | yayun | +--------------------+ 5 rows in set (0.01 sec) [yayun@192.168.0.10][(none)]>
8. 创建表并且写入数据进行查询：
[yayun@192.168.0.10][(none)]> use yayun Database changed, 2 warnings [yayun@192.168.0.10][yayun]> create table t1 ( id int); Query OK, 0 rows affected (0.08 sec) [yayun@192.168.0.10][yayun]> insert into t1 select 1; Query OK, 1 row affected (0.05 sec) Records: 1 Duplicates: 0 Warnings: 0 [yayun@192.168.0.10][yayun]> select * from t1; +------+ | id | +------+ | 1 | +------+ 1 row in set (0.00 sec) [yayun@192.168.0.10][yayun]>
可以看到创建了表，并且插入了数据，查询也没问题。proxysql有个类似审计的功能，可以查看各类SQL的执行情况。在proxysql执行SQL查看。
[admin@127.0.0.1][(none)]> select * from stats_mysql_query_digest; +-----------+--------------------+----------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+ | hostgroup | schemaname | username | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time | +-----------+--------------------+----------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+ | 100 | yayun | yayun | 0xA9518ABEA63705E6 | create table t1 ( id int) | 1 | 1497577980 | 1497577980 | 79733 | 79733 | 79733 | | 100 | yayun | yayun | 0x3765930C7143F468 | select * from t1 | 1 | 1497577997 | 1497577997 | 1537 | 1537 | 1537 | | 100 | yayun | yayun | 0x4BBB5CD4BC2CFD94 | insert into t1 select ? | 1 | 1497577986 | 1497577986 | 33350 | 33350 | 33350 | | 100 | information_schema | yayun | 0x620B328FE9D6D71A | SELECT DATABASE() | 1 | 1497577955 | 1497577955 | 4994 | 4994 | 4994 | | 100 | information_schema | yayun | 0x594F2C744B698066 | select USER() | 1 | 1497577951 | 1497577951 | 0 | 0 | 0 | | 100 | information_schema | yayun | 0x226CD90D52A2BA0B | select @@version_comment limit ? | 1 | 1497577951 | 1497577951 | 0 | 0 | 0 | +-----------+--------------------+----------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+ 6 rows in set (0.00 sec) [admin@127.0.0.1][(none)]>
9. 可以看到读写都发送到了组100上面，组100是主库，说明没有读写分离。那是因为还有配置没有完成，我们需要自己定义规则。
定义路由规则，如：除select * from tb for update的select全部发送到slave，其他的的语句发送到master。
[admin@127.0.0.1][(none)]> INSERT INTO mysql_query_rules(active,match_pattern,destination_hostgroup,apply) VALUES(1,'^SELECT.*FOR UPDATE$',100,1); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> INSERT INTO mysql_query_rules(active,match_pattern,destination_hostgroup,apply) VALUES(1,'^SELECT',1000,1); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> load mysql query rules to runtime; Query OK, 0 rows affected (0.00 sec) [admin@127.0.0.1][(none)]> save mysql query rules to disk; Query OK, 0 rows affected (0.02 sec) [admin@127.0.0.1][(none)]> select rule_id,active,match_pattern,destination_hostgroup,apply from runtime_mysql_query_rules; +---------+--------+----------------------+-----------------------+-------+ | rule_id | active | match_pattern | destination_hostgroup | apply | +---------+--------+----------------------+-----------------------+-------+ | 1 | 1 | ^SELECT.*FOR UPDATE$ | 100 | 1 | | 2 | 1 | ^SELECT | 1000 | 1 | +---------+--------+----------------------+-----------------------+-------+ 2 rows in set (0.00 sec) [admin@127.0.0.1][(none)]>
清理掉统计信息，再次进行测试。
select * from stats_mysql_query_digest_reset;
再次运行读写，然后再查看，发现已经实现读写分离。
[admin@127.0.0.1][(none)]> select * from stats_mysql_query_digest; +-----------+------------+----------+--------------------+-------------------------+------------+------------+------------+----------+----------+----------+ | hostgroup | schemaname | username | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time | +-----------+------------+----------+--------------------+-------------------------+------------+------------+------------+----------+----------+----------+ | 1000 | yayun | yayun | 0x3765930C7143F468 | select * from t1 | 1 | 1497578494 | 1497578494 | 21751 | 21751 | 21751 | | 100 | yayun | yayun | 0x4BBB5CD4BC2CFD94 | insert into t1 select ? | 1 | 1497578492 | 1497578492 | 54852 | 54852 | 54852 | +-----------+------------+----------+--------------------+-------------------------+------------+------------+------------+----------+----------+----------+ 2 rows in set (0.00 sec) [admin@127.0.0.1][(none)]>
重点来了，如何配合MHA实现高可用呢？那么需要利用到proxysql里面的mysql_replication_hostgroups表。mysql_replication_hostgroups 表的主要作用是监视指定主机组中所有服务器的read_only值，并且根据read_only的值将服务器分配给写入器或读取器主机组，定义 hostgroup 的主从关系。ProxySQL monitor 模块会监控 HG 后端所有servers 的 read_only 变量，如果发现从库的 read_only 变为0、主库变为1，则认为角色互换了，自动改写 mysql_servers 表里面 hostgroup 关系，达到自动 Failover 效果。
我们看看mysql_replication_hostgroups表结构：
[admin@127.0.0.1][(none)]> show create table mysql_replication_hostgroups\G *************************** 1. row *************************** table: mysql_replication_hostgroups Create Table: CREATE TABLE mysql_replication_hostgroups ( writer_hostgroup INT CHECK (writer_hostgroup>=0) NOT NULL PRIMARY KEY, reader_hostgroup INT NOT NULL CHECK (reader_hostgroup<>writer_hostgroup AND reader_hostgroup>0), comment VARCHAR, UNIQUE (reader_hostgroup)) 1 row in set (0.00 sec) [admin@127.0.0.1][(none)]>
3个字段很明显，写主机组，读主机组，备注。那么我们现在插入数据。我们的100是写，1000是读。
[admin@127.0.0.1][(none)]> insert into mysql_replication_hostgroups (writer_hostgroup,reader_hostgroup,comment)values(100,1000,'测试我的读写分离高可用'); Query OK, 1 row affected (0.00 sec) [admin@127.0.0.1][(none)]> load mysql servers to runtime; Query OK, 0 rows affected (0.01 sec) [admin@127.0.0.1][(none)]> save mysql servers to disk; Query OK, 0 rows affected (0.03 sec) [admin@127.0.0.1][(none)]> select * from runtime_mysql_replication_hostgroups; +------------------+------------------+-----------------------------------+ | writer_hostgroup | reader_hostgroup | comment | +------------------+------------------+-----------------------------------+ | 100 | 1000 | 测试我的读写分离高可用 | +------------------+------------------+-----------------------------------+ 1 row in set (0.00 sec) [admin@127.0.0.1][(none)]>
我们用vc-mysql-sniffer在从库抓一下。看看能看见什么。
[root@db_server_yayun_03 ~]# ./vc-mysql-sniffer # Time: 061617 10:26:45 # User@Host: unknown_user[unknown_user] @ 192.168.0.10:36371 [] # Query_time: 0.005198 SHOW GLOBAL VARIABLES LIKE 'read_only'; # Time: 061617 10:26:46 # User@Host: unknown_user[unknown_user] @ 192.168.0.10:36372 [] # Query_time: 0.000564 SHOW SLAVE STATUS; # Time: 061617 10:26:46 # User@Host: unknown_user[unknown_user] @ 192.168.0.10:36372 [] # Query_time: 0.004008 SHOW GLOBAL VARIABLES LIKE 'read_only'; # Time: 061617 10:26:48 # User@Host: unknown_user[unknown_user] @ 192.168.0.10:36371 [] # Query_time: 0.004923 SHOW GLOBAL VARIABLES LIKE 'read_only'; # Time: 061617 10:26:49 # User@Host: unknown_user[unknown_user] @ 192.168.0.10:36372 [] # Query_time: 0.003617 SHOW GLOBAL VARIABLES LIKE 'read_only';
可以看见在检查read_only变量。我们先看看现在主机组的关系：
[admin@127.0.0.1][(none)]> select * from runtime_mysql_servers; +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | 100 | 192.168.0.20 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.30 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.40 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ 3 rows in set (0.00 sec) [admin@127.0.0.1][(none)]>
可以看见100主机组是主库，1000主机组是从库。下面使用MHA在线变换主从关系。我们把从库40提升为主库。
[root@db_server_yayun_04 ~]# masterha_master_switch --master_state=alive --conf=/data/mha/3306/mha.cnf --new_master_host=192.168.0.40 --new_master_port=3306 --orig_master_is_new_slave Fri Jun 16 10:30:39 2017 - [info] MHA::MasterRotate version 0.57. Fri Jun 16 10:30:39 2017 - [info] Starting online master switch.. Fri Jun 16 10:30:39 2017 - [info] Fri Jun 16 10:30:39 2017 - [info] * Phase 1: Configuration Check Phase.. Fri Jun 16 10:30:39 2017 - [info] Fri Jun 16 10:30:39 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Fri Jun 16 10:30:39 2017 - [info] Reading application default configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:30:39 2017 - [info] Updating application default configuration from /usr/local/bin/load_cnf.. Fri Jun 16 10:30:39 2017 - [info] Reading server configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:30:39 2017 - [info] Setting max_ping_errors to 10, ping_interval to 3. Fri Jun 16 10:30:39 2017 - [info] GTID failover mode = 1 Fri Jun 16 10:30:39 2017 - [info] Current Alive Master: 192.168.0.20(192.168.0.20:3306) Fri Jun 16 10:30:39 2017 - [info] Alive Slaves: Fri Jun 16 10:30:39 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:30:39 2017 - [info] GTID ON Fri Jun 16 10:30:39 2017 - [info] Replicating from 192.168.0.20(192.168.0.20:3306) Fri Jun 16 10:30:39 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:30:39 2017 - [info] 192.168.0.40(192.168.0.40:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:30:39 2017 - [info] GTID ON Fri Jun 16 10:30:39 2017 - [info] Replicating from 192.168.0.20(192.168.0.20:3306) Fri Jun 16 10:30:39 2017 - [info] Primary candidate for the new Master (candidate_master is set) It is better to execute FLUSH NO_WRITE_TO_BINLOG TABLES on the master before switching. Is it ok to execute on 192.168.0.20(192.168.0.20:3306)? (YES/no): y Fri Jun 16 10:30:40 2017 - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time.. Fri Jun 16 10:30:40 2017 - [info] ok. Fri Jun 16 10:30:40 2017 - [info] Checking MHA is not monitoring or doing failover.. Fri Jun 16 10:30:40 2017 - [info] Checking replication health on 192.168.0.30.. Fri Jun 16 10:30:40 2017 - [info] ok. Fri Jun 16 10:30:40 2017 - [info] Checking replication health on 192.168.0.40.. Fri Jun 16 10:30:40 2017 - [info] ok. Fri Jun 16 10:30:40 2017 - [info] 192.168.0.40 can be new master. Fri Jun 16 10:30:40 2017 - [info] From: 192.168.0.20(192.168.0.20:3306) (current master) +--192.168.0.30(192.168.0.30:3306) +--192.168.0.40(192.168.0.40:3306) To: 192.168.0.40(192.168.0.40:3306) (new master) +--192.168.0.30(192.168.0.30:3306) +--192.168.0.20(192.168.0.20:3306) Starting master switch from 192.168.0.20(192.168.0.20:3306) to 192.168.0.40(192.168.0.40:3306)? (yes/NO): yes Fri Jun 16 10:30:42 2017 - [info] Checking whether 192.168.0.40(192.168.0.40:3306) is ok for the new master.. Fri Jun 16 10:30:42 2017 - [info] ok. Fri Jun 16 10:30:42 2017 - [info] 192.168.0.20(192.168.0.20:3306): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host. Fri Jun 16 10:30:42 2017 - [info] 192.168.0.20(192.168.0.20:3306): Resetting slave pointing to the dummy host. Fri Jun 16 10:30:42 2017 - [info] ** Phase 1: Configuration Check Phase completed. Fri Jun 16 10:30:42 2017 - [info] Fri Jun 16 10:30:42 2017 - [info] * Phase 2: Rejecting updates Phase.. Fri Jun 16 10:30:42 2017 - [info] Fri Jun 16 10:30:42 2017 - [info] Executing master ip online change script to disable write on the current master: Fri Jun 16 10:30:42 2017 - [info] /usr/local/bin/master_ip_online_change --command=stop --orig_master_host=192.168.0.20 --orig_master_ip=192.168.0.20 --orig_master_port=3306 --orig_master_user='root' --orig_master_password='123' --new_master_host=192.168.0.40 --new_master_ip=192.168.0.40 --new_master_port=3306 --new_master_user='root' --new_master_password='123' --orig_master_ssh_user=root --new_master_ssh_user=root --orig_master_is_new_slave Fri Jun 16 10:30:42 2017 783184 Set read_only on the new master.. ok. Fri Jun 16 10:30:42 2017 786894 Drpping app user on the orig master.. Fri Jun 16 10:30:42 2017 787716 Waiting all running 3 threads are disconnected.. (max 1500 milliseconds) {'Time' => '0','Command' => 'Sleep','db' => undef,'Id' => '282','Info' => undef,'User' => 'proxysql','State' => '','Host' => '192.168.0.10:54482'} {'Time' => '1620','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '296','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.30:53451'} {'Time' => '874','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '310','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.40:53136'} Fri Jun 16 10:30:43 2017 294399 Waiting all running 2 threads are disconnected.. (max 1000 milliseconds) {'Time' => '1621','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '296','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.30:53451'} {'Time' => '875','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '310','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.40:53136'} Fri Jun 16 10:30:43 2017 800400 Waiting all running 2 threads are disconnected.. (max 500 milliseconds) {'Time' => '1621','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '296','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.30:53451'} {'Time' => '875','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '310','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.40:53136'} Fri Jun 16 10:30:44 2017 306937 Set read_only=1 on the orig master.. ok. Fri Jun 16 10:30:44 2017 311939 Waiting all running 3 queries are disconnected.. (max 500 milliseconds) {'Time' => '0','Command' => 'Sleep','db' => undef,'Id' => '281','Info' => undef,'User' => 'proxysql','State' => '','Host' => '192.168.0.10:54481'} {'Time' => '1622','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '296','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.30:53451'} {'Time' => '876','Command' => 'Binlog Dump GTID','db' => undef,'Id' => '310','Info' => undef,'User' => 'repl','State' => 'Master has sent all binlog to slave; waiting for more updates','Host' => '192.168.0.40:53136'} Fri Jun 16 10:30:44 2017 810421 Killing all application threads.. Fri Jun 16 10:30:44 2017 816513 done. SIOCSIFFLAGS: Cannot assign requested address Fri Jun 16 10:30:45 2017 - [info] ok. Fri Jun 16 10:30:45 2017 - [info] Locking all tables on the orig master to reject updates from everybody (including root): Fri Jun 16 10:30:45 2017 - [info] Executing FLUSH TABLES WITH READ LOCK.. Fri Jun 16 10:30:45 2017 - [info] ok. Fri Jun 16 10:30:45 2017 - [info] Orig master binlog:pos is mysql-bin.000001:1610. Fri Jun 16 10:30:45 2017 - [info] Waiting to execute all relay logs on 192.168.0.40(192.168.0.40:3306).. Fri Jun 16 10:30:45 2017 - [info] master_pos_wait(mysql-bin.000001:1610) completed on 192.168.0.40(192.168.0.40:3306). Executed 0 events. Fri Jun 16 10:30:45 2017 - [info] done. Fri Jun 16 10:30:45 2017 - [info] Getting new master's binlog name and position.. Fri Jun 16 10:30:45 2017 - [info] mysql-bin.000002:194 Fri Jun 16 10:30:45 2017 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.0.40', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx'; Fri Jun 16 10:30:45 2017 - [info] Executing master ip online change script to allow write on the new master: Fri Jun 16 10:30:45 2017 - [info] /usr/local/bin/master_ip_online_change --command=start --orig_master_host=192.168.0.20 --orig_master_ip=192.168.0.20 --orig_master_port=3306 --orig_master_user='root' --orig_master_password='123' --new_master_host=192.168.0.40 --new_master_ip=192.168.0.40 --new_master_port=3306 --new_master_user='root' --new_master_password='123' --orig_master_ssh_user=root --new_master_ssh_user=root --orig_master_is_new_slave Fri Jun 16 10:30:45 2017 744690 Set read_only=0 on the new master. Fri Jun 16 10:30:45 2017 745124 Creating app user on the new master.. Fri Jun 16 10:30:45 2017 - [info] ok. Fri Jun 16 10:30:45 2017 - [info] Fri Jun 16 10:30:45 2017 - [info] * Switching slaves in parallel.. Fri Jun 16 10:30:45 2017 - [info] Fri Jun 16 10:30:45 2017 - [info] -- Slave switch on host 192.168.0.30(192.168.0.30:3306) started, pid: 9457 Fri Jun 16 10:30:45 2017 - [info] Fri Jun 16 10:30:45 2017 - [info] Log messages from 192.168.0.30 ... Fri Jun 16 10:30:45 2017 - [info] Fri Jun 16 10:30:45 2017 - [info] Waiting to execute all relay logs on 192.168.0.30(192.168.0.30:3306).. Fri Jun 16 10:30:45 2017 - [info] master_pos_wait(mysql-bin.000001:1610) completed on 192.168.0.30(192.168.0.30:3306). Executed 0 events. Fri Jun 16 10:30:45 2017 - [info] done. Fri Jun 16 10:30:45 2017 - [info] Resetting slave 192.168.0.30(192.168.0.30:3306) and starting replication from the new master 192.168.0.40(192.168.0.40:3306).. Fri Jun 16 10:30:45 2017 - [info] Executed CHANGE MASTER. Fri Jun 16 10:30:45 2017 - [info] Slave started. Fri Jun 16 10:30:45 2017 - [info] End of log messages from 192.168.0.30 ... Fri Jun 16 10:30:45 2017 - [info] Fri Jun 16 10:30:45 2017 - [info] -- Slave switch on host 192.168.0.30(192.168.0.30:3306) succeeded. Fri Jun 16 10:30:45 2017 - [info] Unlocking all tables on the orig master: Fri Jun 16 10:30:45 2017 - [info] Executing UNLOCK TABLES.. Fri Jun 16 10:30:45 2017 - [info] ok. Fri Jun 16 10:30:45 2017 - [info] Starting orig master as a new slave.. Fri Jun 16 10:30:45 2017 - [info] Resetting slave 192.168.0.20(192.168.0.20:3306) and starting replication from the new master 192.168.0.40(192.168.0.40:3306).. Fri Jun 16 10:30:45 2017 - [info] Executed CHANGE MASTER. Fri Jun 16 10:30:46 2017 - [info] Slave started. Fri Jun 16 10:30:46 2017 - [info] All new slave servers switched successfully. Fri Jun 16 10:30:46 2017 - [info] Fri Jun 16 10:30:46 2017 - [info] * Phase 5: New master cleanup phase.. Fri Jun 16 10:30:46 2017 - [info] Fri Jun 16 10:30:46 2017 - [info] 192.168.0.40: Resetting slave info succeeded. Fri Jun 16 10:30:46 2017 - [info] Switching master to 192.168.0.40(192.168.0.40:3306) completed successfully.
可以看见已经成功切换。我们再来看看运行主机组的状态：
[admin@127.0.0.1][(none)]> select * from runtime_mysql_servers; +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | 100 | 192.168.0.40 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.30 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.40 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.20 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ 4 rows in set (0.00 sec) [admin@127.0.0.1][(none)]>
可以看见40自动设置成了主机组100，也就是master。我们进行读写测试。
[admin@127.0.0.1][(none)]> select * from stats_mysql_query_digest; +-----------+------------+----------+--------------------+-----------------------------+------------+------------+------------+----------+----------+----------+ | hostgroup | schemaname | username | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time | +-----------+------------+----------+--------------------+-----------------------------+------------+------------+------------+----------+----------+----------+ | 1000 | yayun | yayun | 0x3765930C7143F468 | select * from t1 | 1 | 1497580568 | 1497580568 | 34920 | 34920 | 34920 | | 100 | yayun | yayun | 0x5A680F86B3D8FB2B | select * from t1 for update | 1 | 1497580565 | 1497580565 | 9609 | 9609 | 9609 | | 100 | yayun | yayun | 0x4BBB5CD4BC2CFD94 | insert into t1 select ? | 1 | 1497580557 | 1497580557 | 133003 | 133003 | 133003 | | 100 | yayun | yayun | 0x99531AEFF718C501 | show tables | 1 | 1497580544 | 1497580544 | 2051 | 2051 | 2051 | | 100 | yayun | yayun | 0x74A739578E179F19 | show processlist | 1 | 1497580532 | 1497580532 | 4335 | 4335 | 4335 | +-----------+------------+----------+--------------------+-----------------------------+------------+------------+------------+----------+----------+----------+ 5 rows in set (0.00 sec) [admin@127.0.0.1][(none)]>
可以看见除了for update语句和insert发送到主库，查询是发送到了从库。当然虽然1000主机组里面有40，也就是会有非常少量的查询才会发送到主库。这个没法避免。
下面进行主库宕机测试，启动mha监控，关闭主库。mha切换日志，可以看见30当选主库：
[root@db_server_yayun_04 log]# cat manager.log Fri Jun 16 10:38:59 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Fri Jun 16 10:38:59 2017 - [info] Reading application default configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:38:59 2017 - [info] Updating application default configuration from /usr/local/bin/load_cnf.. Fri Jun 16 10:38:59 2017 - [info] Reading server configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:38:59 2017 - [info] Setting max_ping_errors to 10, ping_interval to 3. Fri Jun 16 10:39:53 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Fri Jun 16 10:39:53 2017 - [info] Reading application default configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:39:53 2017 - [info] Updating application default configuration from /usr/local/bin/load_cnf.. Fri Jun 16 10:39:53 2017 - [info] Reading server configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:39:53 2017 - [info] Setting max_ping_errors to 10, ping_interval to 3. nfo] 192.168.0.20(192.168.0.20:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:38:59 2017 - [info] GTID ON Fri Jun 16 10:38:59 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:38:59 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:38:59 2017 - [info] GTID ON Fri Jun 16 10:38:59 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:38:59 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:38:59 2017 - [info] Current Alive Master: 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:38:59 2017 - [info] Checking slave configurations.. Fri Jun 16 10:38:59 2017 - [info] Checking replication filtering settings.. Fri Jun 16 10:38:59 2017 - [info] binlog_do_db= , binlog_ignore_db= Fri Jun 16 10:38:59 2017 - [info] Replication filtering check ok. Fri Jun 16 10:38:59 2017 - [info] GTID (with auto-pos) is supported. Skipping all SSH and Node package checking. Fri Jun 16 10:38:59 2017 - [info] Checking SSH publickey authentication settings on the current master.. Fri Jun 16 10:38:59 2017 - [info] HealthCheck: SSH to 192.168.0.40 is reachable. Fri Jun 16 10:38:59 2017 - [info] 192.168.0.40(192.168.0.40:3306) (current master) +--192.168.0.20(192.168.0.20:3306) +--192.168.0.30(192.168.0.30:3306) Fri Jun 16 10:38:59 2017 - [warning] master_ip_failover_script is not defined. Fri Jun 16 10:38:59 2017 - [warning] shutdown_script is not defined. Fri Jun 16 10:38:59 2017 - [info] Set master ping interval 3 seconds. Fri Jun 16 10:38:59 2017 - [warning] secondary_check_script is not defined. It is highly recommended setting it to check master reachability from two or more routes. Fri Jun 16 10:38:59 2017 - [info] Starting ping health check on 192.168.0.40(192.168.0.40:3306).. Fri Jun 16 10:38:59 2017 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond.. Fri Jun 16 10:39:26 2017 - [warning] Got error on MySQL select ping: 2006 (MySQL server has gone away) Fri Jun 16 10:39:26 2017 - [info] Executing SSH check script: exit 0 Fri Jun 16 10:39:27 2017 - [info] HealthCheck: SSH to 192.168.0.40 is reachable. Fri Jun 16 10:39:29 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:29 2017 - [warning] Connection failed 2 time(s).. Fri Jun 16 10:39:32 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:32 2017 - [warning] Connection failed 3 time(s).. Fri Jun 16 10:39:35 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:35 2017 - [warning] Connection failed 4 time(s).. Fri Jun 16 10:39:38 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:38 2017 - [warning] Connection failed 5 time(s).. Fri Jun 16 10:39:41 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:41 2017 - [warning] Connection failed 6 time(s).. Fri Jun 16 10:39:44 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:44 2017 - [warning] Connection failed 7 time(s).. Fri Jun 16 10:39:47 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:47 2017 - [warning] Connection failed 8 time(s).. Fri Jun 16 10:39:50 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:50 2017 - [warning] Connection failed 9 time(s).. Fri Jun 16 10:39:53 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at 'reading initial communication packet', system error: 111) Fri Jun 16 10:39:53 2017 - [warning] Connection failed 10 time(s).. Fri Jun 16 10:39:53 2017 - [warning] Master is not reachable from health checker! Fri Jun 16 10:39:53 2017 - [warning] Master 192.168.0.40(192.168.0.40:3306) is not reachable! Fri Jun 16 10:39:53 2017 - [warning] SSH is reachable. Fri Jun 16 10:39:53 2017 - [info] Connecting to a master server failed. Reading configuration file /etc/masterha_default.cnf and /data/mha/3306/mha.cnf again, and trying to connect to all servers to check server status.. Fri Jun 16 10:39:53 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping. Fri Jun 16 10:39:53 2017 - [info] Reading application default configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:39:53 2017 - [info] Updating application default configuration from /usr/local/bin/load_cnf.. Fri Jun 16 10:39:53 2017 - [info] Reading server configuration from /data/mha/3306/mha.cnf.. Fri Jun 16 10:39:53 2017 - [info] Setting max_ping_errors to 10, ping_interval to 3. Fri Jun 16 10:39:53 2017 - [info] GTID failover mode = 1 Fri Jun 16 10:39:53 2017 - [info] Dead Servers: Fri Jun 16 10:39:53 2017 - [info] 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:53 2017 - [info] Alive Servers: Fri Jun 16 10:39:53 2017 - [info] 192.168.0.20(192.168.0.20:3306) Fri Jun 16 10:39:53 2017 - [info] 192.168.0.30(192.168.0.30:3306) Fri Jun 16 10:39:53 2017 - [info] Alive Slaves: Fri Jun 16 10:39:53 2017 - [info] 192.168.0.20(192.168.0.20:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:53 2017 - [info] GTID ON Fri Jun 16 10:39:53 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:53 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:53 2017 - [info] GTID ON Fri Jun 16 10:39:53 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:53 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:39:53 2017 - [info] Checking slave configurations.. Fri Jun 16 10:39:53 2017 - [info] Checking replication filtering settings.. Fri Jun 16 10:39:53 2017 - [info] Replication filtering check ok. Fri Jun 16 10:39:53 2017 - [info] Master is down! Fri Jun 16 10:39:53 2017 - [info] Terminating monitoring script. Fri Jun 16 10:39:53 2017 - [info] Got exit code 20 (Master dead). Fri Jun 16 10:39:53 2017 - [info] MHA::MasterFailover version 0.57. Fri Jun 16 10:39:53 2017 - [info] Starting master failover. Fri Jun 16 10:39:53 2017 - [info] Fri Jun 16 10:39:53 2017 - [info] * Phase 1: Configuration Check Phase.. Fri Jun 16 10:39:53 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] GTID failover mode = 1 Fri Jun 16 10:39:54 2017 - [info] Dead Servers: Fri Jun 16 10:39:54 2017 - [info] 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] Checking master reachability via MySQL(double check)... Fri Jun 16 10:39:54 2017 - [info] ok. Fri Jun 16 10:39:54 2017 - [info] Alive Servers: Fri Jun 16 10:39:54 2017 - [info] 192.168.0.20(192.168.0.20:3306) Fri Jun 16 10:39:54 2017 - [info] 192.168.0.30(192.168.0.30:3306) Fri Jun 16 10:39:54 2017 - [info] Alive Slaves: Fri Jun 16 10:39:54 2017 - [info] 192.168.0.20(192.168.0.20:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:39:54 2017 - [info] Starting GTID based failover. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] ** Phase 1: Configuration Check Phase completed. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 2: Dead Master Shutdown Phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Forcing shutdown so that applications never connect to the current master.. Fri Jun 16 10:39:54 2017 - [warning] master_ip_failover_script is not set. Skipping invalidating dead master IP address. Fri Jun 16 10:39:54 2017 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master. Fri Jun 16 10:39:54 2017 - [info] * Phase 2: Dead Master Shutdown Phase completed. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 3: Master Recovery Phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 3.1: Getting Latest Slaves Phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] The latest binary log file/position on all slaves is mysql-bin.000002:497 Fri Jun 16 10:39:54 2017 - [info] Retrieved Gtid Set: 900f20f2-f48c-11e6-8d78-000c2930a8b9:1 Fri Jun 16 10:39:54 2017 - [info] Latest slaves (Slaves that received relay log files to the latest): Fri Jun 16 10:39:54 2017 - [info] 192.168.0.20(192.168.0.20:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:39:54 2017 - [info] The oldest binary log file/position on all slaves is mysql-bin.000002:497 Fri Jun 16 10:39:54 2017 - [info] Retrieved Gtid Set: 900f20f2-f48c-11e6-8d78-000c2930a8b9:1 Fri Jun 16 10:39:54 2017 - [info] Oldest slaves: Fri Jun 16 10:39:54 2017 - [info] 192.168.0.20(192.168.0.20:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 3.3: Determining New Master Phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Searching new master from slaves.. Fri Jun 16 10:39:54 2017 - [info] Candidate masters from the configuration file: Fri Jun 16 10:39:54 2017 - [info] 192.168.0.30(192.168.0.30:3306) Version=5.7.17-log (oldest major version between slaves) log-bin:enabled Fri Jun 16 10:39:54 2017 - [info] GTID ON Fri Jun 16 10:39:54 2017 - [info] Replicating from 192.168.0.40(192.168.0.40:3306) Fri Jun 16 10:39:54 2017 - [info] Primary candidate for the new Master (candidate_master is set) Fri Jun 16 10:39:54 2017 - [info] Non-candidate masters: Fri Jun 16 10:39:54 2017 - [info] Searching from candidate_master slaves which have received the latest relay log events.. Fri Jun 16 10:39:54 2017 - [info] New master is 192.168.0.30(192.168.0.30:3306) Fri Jun 16 10:39:54 2017 - [info] Starting master failover.. Fri Jun 16 10:39:54 2017 - [info] From: 192.168.0.40(192.168.0.40:3306) (current master) +--192.168.0.20(192.168.0.20:3306) +--192.168.0.30(192.168.0.30:3306) To: 192.168.0.30(192.168.0.30:3306) (new master) +--192.168.0.20(192.168.0.20:3306) Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 3.3: New Master Recovery Phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Waiting all logs to be applied.. Fri Jun 16 10:39:54 2017 - [info] done. Fri Jun 16 10:39:54 2017 - [info] Replicating from the latest slave 192.168.0.20(192.168.0.20:3306) and waiting to apply.. Fri Jun 16 10:39:54 2017 - [info] Waiting all logs to be applied on the latest slave.. Fri Jun 16 10:39:54 2017 - [info] Resetting slave 192.168.0.30(192.168.0.30:3306) and starting replication from the new master 192.168.0.20(192.168.0.20:3306).. Fri Jun 16 10:39:54 2017 - [info] Executed CHANGE MASTER. Fri Jun 16 10:39:54 2017 - [info] Slave started. Fri Jun 16 10:39:54 2017 - [info] Waiting to execute all relay logs on 192.168.0.30(192.168.0.30:3306).. Fri Jun 16 10:39:54 2017 - [info] master_pos_wait(mysql-bin.000001:1879) completed on 192.168.0.30(192.168.0.30:3306). Executed 4 events. Fri Jun 16 10:39:54 2017 - [info] done. Fri Jun 16 10:39:54 2017 - [info] done. Fri Jun 16 10:39:54 2017 - [info] Getting new master's binlog name and position.. Fri Jun 16 10:39:54 2017 - [info] mysql-bin.000002:459 Fri Jun 16 10:39:54 2017 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.0.30', MASTER_PORT=3306, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='xxx'; Fri Jun 16 10:39:54 2017 - [info] Master Recovery succeeded. File:Pos:Exec_Gtid_Set: mysql-bin.000002, 459, 56195f28-36e2-11e7-991b-000c29e3f5ab:1-6, 900f20f2-f48c-11e6-8d78-000c2930a8b9:1 Fri Jun 16 10:39:54 2017 - [warning] master_ip_failover_script is not set. Skipping taking over new master IP address. Fri Jun 16 10:39:54 2017 - [info] Setting read_only=0 on 192.168.0.30(192.168.0.30:3306).. Fri Jun 16 10:39:54 2017 - [info] ok. Fri Jun 16 10:39:54 2017 - [info] ** Finished master recovery successfully. Fri Jun 16 10:39:54 2017 - [info] * Phase 3: Master Recovery Phase completed. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 4: Slaves Recovery Phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 4.1: Starting Slaves in parallel.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] -- Slave recovery on host 192.168.0.20(192.168.0.20:3306) started, pid: 9905. Check tmp log /data/mha/3306/log/192.168.0.20_3306_20170616103953.log if it takes time.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Log messages from 192.168.0.20 ... Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Resetting slave 192.168.0.20(192.168.0.20:3306) and starting replication from the new master 192.168.0.30(192.168.0.30:3306).. Fri Jun 16 10:39:54 2017 - [info] Executed CHANGE MASTER. Fri Jun 16 10:39:54 2017 - [info] Slave started. Fri Jun 16 10:39:54 2017 - [info] gtid_wait(56195f28-36e2-11e7-991b-000c29e3f5ab:1-6, 900f20f2-f48c-11e6-8d78-000c2930a8b9:1) completed on 192.168.0.20(192.168.0.20:3306). Executed 0 events. Fri Jun 16 10:39:54 2017 - [info] End of log messages from 192.168.0.20. Fri Jun 16 10:39:54 2017 - [info] -- Slave on host 192.168.0.20(192.168.0.20:3306) started. Fri Jun 16 10:39:54 2017 - [info] All new slave servers recovered successfully. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] * Phase 5: New master cleanup phase.. Fri Jun 16 10:39:54 2017 - [info] Fri Jun 16 10:39:54 2017 - [info] Resetting slave info on the new master.. Fri Jun 16 10:39:54 2017 - [info] 192.168.0.30: Resetting slave info succeeded. Fri Jun 16 10:39:54 2017 - [info] Master failover to 192.168.0.30(192.168.0.30:3306) completed successfully. Fri Jun 16 10:39:54 2017 - [info] ----- Failover Report ----- mha: MySQL Master failover 192.168.0.40(192.168.0.40:3306) to 192.168.0.30(192.168.0.30:3306) succeeded Master 192.168.0.40(192.168.0.40:3306) is down! Check MHA Manager logs at db_server_yayun_04:/data/mha/3306/log/manager.log for details. Started automated(non-interactive) failover. Selected 192.168.0.30(192.168.0.30:3306) as a new master. 192.168.0.30(192.168.0.30:3306): OK: Applying all logs succeeded. 192.168.0.20(192.168.0.20:3306): OK: Slave started, replicating from 192.168.0.30(192.168.0.30:3306) 192.168.0.30(192.168.0.30:3306): Resetting slave info succeeded. Master failover to 192.168.0.30(192.168.0.30:3306) completed successfully.
再来看看proxysql里面现在主机组的情况：
[admin@127.0.0.1][(none)]> select * from runtime_mysql_servers; +--------------+--------------+------+---------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+---------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ | 100 | 192.168.0.30 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.30 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.40 | 3306 | SHUNNED | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | | 1000 | 192.168.0.20 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 100 | test my proxysql | +--------------+--------------+------+---------+--------+-------------+-----------------+---------------------+---------+----------------+------------------+ 4 rows in set (0.01 sec) [admin@127.0.0.1][(none)]>
可以看见40已经是SHUNNED状态，这个已经自动被踢出。30当选主库，自动被设置在主机组100. 再次运行读写测试：
[admin@127.0.0.1][(none)]> select * from stats_mysql_query_digest; +-----------+--------------------+----------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+ | hostgroup | schemaname | username | digest | digest_text | count_star | first_seen | last_seen | sum_time | min_time | max_time | +-----------+--------------------+----------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+ | 100 | yayun | yayun | 0x4BBB5CD4BC2CFD94 | insert into t1 select ? | 1 | 1497581038 | 1497581038 | 114743 | 114743 | 114743 | | 1000 | information_schema | yayun | 0x620B328FE9D6D71A | SELECT DATABASE() | 1 | 1497581026 | 1497581026 | 31128 | 31128 | 31128 | | 100 | information_schema | yayun | 0x594F2C744B698066 | select USER() | 1 | 1497581025 | 1497581025 | 0 | 0 | 0 | | 1000 | yayun | yayun | 0x3765930C7143F468 | select * from t1 | 1 | 1497581045 | 1497581045 | 3283 | 3283 | 3283 | | 100 | information_schema | yayun | 0x226CD90D52A2BA0B | select @@version_comment limit ? | 1 | 1497581025 | 1497581025 | 0 | 0 | 0 | +-----------+--------------------+----------+--------------------+----------------------------------+------------+------------+------------+----------+----------+----------+ 5 rows in set (0.00 sec)
可以看见依然没有问题。到这里本文就结束了，上面是1主2从，如果是1主1从，那么从挂了怎么办呢？需要额外一条规则，那就是在mysql_servers的hostgroup 1000 里面要插一条主库的记录，然后把weight设小，当读不到从库，回去主库查询。
关于ProxySQL比较详细的文章可以参考如下：
ProxySQL之安装及配置详解
ProxySQL之读写分离与分库路由演示