一文快速掌握MGR集群的部署和运维。
本文详细介绍如何在单机环境下,利用GreatSQL构建一个3节点的MGR集群,并用mysqld_multi进行管理。
为了简单起见,这个MGR集群采用单主(single-primary)模式,不采用多主(multi-primary)模式。
构建完MGR集群后,再添加一个新节点,以及模拟进行滚动升级和切主等其他操作。
除了MySQL官方社区版本外,如果想体验更可靠、稳定、高效的MGR,推荐使用GreatSQL版本。本文采用GreatSQL 8.0.22版本,关于这个版本的说明详见 GreatSQL,打造更好的MGR生态。
P.S,单机模式下,如果要部署多实例并构建MGR集群,要注意避免TCP self-connect的问题,详见 bug#98151,如果采用GreatSQL版本就没这个问题了。
1. 运行环境
GreatSQL二进制包放在 /usr/local/ 下,即 basedir = /usr/local/GreatSQL-8.0.22
。
三个实例按下面规划分配:
实例 | 端口 | datadir |
---|---|---|
GreatSQL-01 | 3306 | /data/GreatSQL/mgr01/ |
GreatSQL-02 | 3307 | /data/GreatSQL/mgr02/ |
GreatSQL-03 | 3308 | /data/GreatSQL/mgr03/ |
2、准备my.cnf配置文件
[mysqld]basedir=/usr/local/GreatSQL-8.0.22log_timestamps=SYSTEMuser = mysqllog_error_verbosity = 3log-bin=binlogbinlog-format=rowlog_slave_updates=ONbinlog_checksum=CRC32master-info-repository=TABLErelay-log-info-repository=TABLEgtid-mode=onenforce-gtid-consistency=truebinlog_transaction_dependency_tracking=writesettransaction_write_set_extraction=XXHASH64slave_parallel_type = LOGICAL_CLOCKslave_parallel_workers=128 #可以设置为逻辑CPU数量的2-4倍sql_require_primary_key=1slave_preserve_commit_order=1slave_checkpoint_period=2#mgrloose-plugin_load_add='mysql_clone.so'loose-plugin_load_add='group_replication.so'#所有节点的group_replication_group_name值必须相同#这是一个标准的UUID格式,可以手动指定,也可以用随机生成的UUIDloose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1"#指定MGR集群各节点的IP+端口,这个端口是专用于MGR的,不是平常所说的mysqld实例端口#如果是在多节点上部署MGR集群时,要注意这个端口是否会被防火墙拦截loose-group_replication_group_seeds= "127.0.0.1:33061,127.0.0.1:33071,127.0.0.1:33081"#不建议启动mysqld的同时也启动MGR服务loose-group_replication_start_on_boot=off#默认不要作为MGR集群引导节点,有需要时再手动执行并立即改回OFF状态loose-group_replication_bootstrap_group=off#当退出MGR后,把该实例设置为read_only,避免误操作写入数据loose-group_replication_exit_state_action=READ_ONLY#一般没什么必要开启流控机制loose-group_replication_flow_control_mode = "DISABLED"#【强烈】建议只用单主模式,如果是实验目的,可以尝试玩玩多主模式loose-group_replication_single_primary_mode=ON[mysqld_multi]mysqld = /usr/local/GreatSQL-8.0.22/bin/mysqldlog = /data/GreatSQL/mysqld_multi.logmysqladmin = /usr/local/GreatSQL-8.0.22/bin/mysqladminuser=root[mysqld3306]datadir=/data/GreatSQL/mgr01socket=/data/GreatSQL/mgr01/mysql.sockport=3306server_id=3306log-error=/data/GreatSQL/mgr01/error.log#指定本节点的IP+端口loose-group_replication_local_address= "127.0.0.1:33061"[mysqld3307]datadir=/data/GreatSQL/mgr02socket=/data/GreatSQL/mgr02/mysql.sockport=3307server_id=3307log-error=/data/GreatSQL/mgr02/error.logloose-group_replication_local_address= "127.0.0.1:33071"[mysqld3308]datadir=/data/GreatSQL/mgr03socket=/data/GreatSQL/mgr03/mysql.sockport=3308server_id=3308log-error=/data/GreatSQL/mgr03/error.logloose-group_replication_local_address= "127.0.0.1:33081"
在这份配置文件中,[mysqld]
这部分内容是所有实例都会读取应用的,而在 [mysqld3306]
这部分配置,才是 3306 端口这个实例所独有的。
在构建MGR集群中,要保证集群各节点的 group_replication_group_name
选项值一样才行,否则就是不同的集群了。
另外,如果有防火墙的话,注意要开放各端口间的访问规则,否则无法启动MGR。
3、初始化MySQL实例
先手动创建相应的datadir,并修改目录属主为mysql用户:
[root@greatsql]# mkdir -p /data/GreatSQL/{mgr01,mgr02,mgr03}[root@greatsql]# chown -R mysql.mysql /data/GreatSQL
执行下面的命令进行MySQL实例初始化,会自动创建InnoDB系统表空间、redo log、undo log的文件:
[root@greatsql]# /usr/local/GreatSQL-8.0.22/bin/mysqld --no-defaults --datadir=/data/GreatSQL/mgr01 --initialize --user=mysql[System] [MY-013169] [Server] /usr/local/GreatSQL-8.0.22/bin/mysqld (mysqld 8.0.22-13) initializing of server in progress as process 18688[System] [MY-013576] [InnoDB] InnoDB initialization has started.[System] [MY-013577] [InnoDB] InnoDB initialization has ended.[Note] [MY-010454] [Server] A temporary password is generated for root@localhost: h<GL%Lr:v66W
可以看到,在输出的日志中打印了root账号的临时密码(最后一行),启动mysqld实例后,首次用这个密码登入,就要立即进行修改,否则其他什么也做不了:
用同样的方法,也分别完成mgr02、mgr03的初始化。
接下来,分别启动三个mysqld实例:
[root@greatsql]# /usr/local/GreatSQL-8.0.22/bin/mysqld_multi start 3306[root@greatsql]# /usr/local/GreatSQL-8.0.22/bin/mysqld_multi start 3307[root@greatsql]# /usr/local/GreatSQL-8.0.22/bin/mysqld_multi start 3308
能看到datadir下的文件目录大概像这样的:
-rw-r----- 1 mysql mysql 56 Jun 4 10:44 auto.cnf-rw-r----- 1 mysql mysql 401 Jun 4 10:46 binlog.000001-rw-r----- 1 mysql mysql 16 Jun 4 10:46 binlog.index-rw------- 1 mysql mysql 1676 Jun 4 10:44 ca-key.pem-rw-r--r-- 1 mysql mysql 1120 Jun 4 10:44 ca.pem-rw-r--r-- 1 mysql mysql 1120 Jun 4 10:44 client-cert.pem-rw------- 1 mysql mysql 1680 Jun 4 10:44 client-key.pem-rw-r----- 1 mysql mysql 8800 Jun 4 10:46 error.log-rw-r----- 1 mysql mysql 196608 Jun 4 10:48 #ib_16384_0.dblwr-rw-r----- 1 mysql mysql 8585216 Jun 4 10:44 #ib_16384_1.dblwr-rw-r----- 1 mysql mysql 6274 Jun 4 10:44 ib_buffer_pool-rw-r----- 1 mysql mysql 12582912 Jun 4 10:46 ibdata1-rw-r----- 1 mysql mysql 50331648 Jun 4 10:48 ib_logfile0-rw-r----- 1 mysql mysql 50331648 Jun 4 10:44 ib_logfile1-rw-r----- 1 mysql mysql 12582912 Jun 4 10:46 ibtmp1drwxr-x--- 2 mysql mysql 168 Jun 4 10:46 #innodb_tempdrwxr-x--- 2 mysql mysql 143 Jun 4 10:44 mysql-rw-r----- 1 mysql mysql 25165824 Jun 4 10:46 mysql.ibdsrwxrwxrwx 1 mysql mysql 0 Jun 4 10:46 mysql.sock-rw------- 1 mysql mysql 6 Jun 4 10:46 mysql.sock.lockdrwxr-x--- 2 mysql mysql 8192 Jun 4 10:46 performance_schema-rw------- 1 mysql mysql 1680 Jun 4 10:44 private_key.pem-rw-r--r-- 1 mysql mysql 452 Jun 4 10:44 public_key.pem-rw-r--r-- 1 mysql mysql 1120 Jun 4 10:44 server-cert.pem-rw------- 1 mysql mysql 1676 Jun 4 10:44 server-key.pemdrwxr-x--- 2 mysql mysql 28 Jun 4 10:44 sys-rw-r----- 1 mysql mysql 10485760 Jun 4 10:48 undo_001-rw-r----- 1 mysql mysql 10485760 Jun 4 10:46 undo_002-rw-r----- 1 mysql mysql 6 Jun 4 10:46 greatsql.pid
4、构建MGR集群
4.1 构建MGR集群前的准备工作
因为在配置文件中已经指定了要加载 group_replication
和 mysql_clone
两个 plugin,如无意外,应该都已经加载成功:
[root@GreatSQL][(3306)]> show plugins;+---------------------------------+----------+--------------------+----------------------+---------+| Name | Status | Type | Library | License |+---------------------------------+----------+--------------------+----------------------+---------+| binlog | ACTIVE | STORAGE ENGINE | NULL | GPL |...| clone | ACTIVE | CLONE | mysql_clone.so | GPL || group_replication | ACTIVE | GROUP REPLICATION | group_replication.so | GPL |+---------------------------------+----------+--------------------+----------------------+---------+
看到确实已经加载了。
如果没有被正确加载,就需要查看日志文件确认什么原因无法加载。
也可以尝试手动加载这两个plugin:
[root@GreatSQL][(3306)]> INSTALL PLUGIN group_replication SONAME 'group_replication.so';[root@GreatSQL][(3306)]> INSTALL PLUGIN clone SONAME 'mysql_clone.so';
clone plugin
的作用后面再介绍。
4.2 配置MGR集群PRIMARY节点
接下来创建MGR所需要的账户,并授权:
[root@GreatSQL][(3306)]> CREATE USER repl@'%' IDENTIFIED WITH MYSQL_NATIVE_PASSWORD BY 'repl';[root@GreatSQL][(3306)]> GRANT REPLICATION SLAVE, BACKUP_ADMIN ON *.* TO `repl`@`%`;
因为是一个刚初始化的干净系统,也为了简单起见,执行下面的命令再重置一下:
[root@GreatSQL][(3306)]> reset master; reset slave all;
【提醒】生产环境中请勿这么做。后面会有其他文章介绍如何对已上线的MGR集群再加入新的节点。
创建MGR复制通道:
[root@GreatSQL][(3306)]> CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='repl' FOR CHANNEL 'group_replication_recovery';
上述所有操作,在其他几个节点上都重复执行一遍。
接着,【重要的一步】来了,登入被选中作为 PRIMARY 节点的mgr01实例,执行下面的命令:
[root@GreatSQL][(3306)]> set global group_replication_bootstrap_group=ON;
这个命令的作用是在MGR集群的PRIMARY节点第一次被启动时,用于引导MGR集群的。集群启动后,记得立即将该选项重置为 OFF。
[root@GreatSQL][(3306)]> set global group_replication_bootstrap_group=OFF;
在其他节点启动时,记住【不要】将选项 group_replication_bootstrap_group
设置为ON,否则会独立拉起一个新的MGR集群。
之后就可以在MGR集群的 PRIMARY 节点上启动组复制线程了:
[root@GreatSQL][(3306)]> start group_replication;Query OK, 0 rows affected (2.14 sec)[root@GreatSQL][(3306)]> select * from performance_schema.replication_group_members;+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 0fbb2cfd-c4d9-11eb-8747-525400e2078a | greatsql-mgr | 3306 | ONLINE | PRIMARY | 8.0.22 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
此时可以看到MGR集群已启动,且只有PRIMARY节点。
接下来在mgr02、mgr03节点上也执行 start group_replication
启动MGR服务,【记得要设置 】group_replication_bootstrap_group=OFF
。
4.3 查看MGR集群状态
所有实例都启动MGR服务后,再次查看集群状态:
[root@GreatSQL][(3308)]> select * from performance_schema.replication_group_members;+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 0fbb2cfd-c4d9-11eb-8747-525400e2078a | greatsql-mgr | 3306 | ONLINE | PRIMARY | 8.0.22 || group_replication_applier | 1778e87a-c4d9-11eb-bf33-525400e2078a | greatsql-mgr | 3307 | ONLINE | SECONDARY | 8.0.22 || group_replication_applier | 1c8ebfa6-c4d9-11eb-80d1-525400e2078a | greatsql-mgr | 3308 | ONLINE | SECONDARY | 8.0.22 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
因为是在同一个主机上启动多实例构建的MGR,所以 MEMBER_HOST 的值是一样的。
一个在单机上由三个实例组成的MGR集群构建完毕。
4.4 测试数据读写
在MGR集群运行过程中,只有PRIMARY节点上允许同时读写数据,其他节点只能只读数据,不能写入。
在PRIMARY节点上,创建新的库表并写入几行数据:
[root@GreatSQL][(3306)]> create database greatsql;[root@GreatSQL][(3306)]> use greatsql;[root@GreatSQL][(3306)][greatsql]> create table t1(id int primary key);[root@GreatSQL][(3306)][greatsql]> insert into t1 values (rand()*1024), (rand()*1024), (rand()*1024);Query OK, 3 rows affected (0.01 sec)Records: 3 Duplicates: 0 Warnings: 0[root@GreatSQL][(3306)][greatsql]> select * from t1;+-----+| id |+-----+| 105 || 423 || 557 |+-----+3 rows in set (0.00 sec)
在另外两个节点上查看数据:
[root@GreatSQL][(3308)]> select * from greatsql.t1;+-----+| id |+-----+| 105 || 423 || 557 |+-----+3 rows in set (0.00 sec)
可以读取到刚新写入的数据。
再次查看MGR的applier线程工作状态:
[root@GreatSQL][(3306)]> select * from performance_schema.replication_connection_status where channel_name = 'group_replication_applier'G*************************** 1. row *************************** CHANNEL_NAME: group_replication_applier GROUP_NAME: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1 SOURCE_UUID: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1 THREAD_ID: NULL SERVICE_STATE: ON <---状态为ON,正常 COUNT_RECEIVED_HEARTBEATS: 0 LAST_HEARTBEAT_TIMESTAMP: 0000-00-00 00:00:00.000000 RECEIVED_TRANSACTION_SET: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1:1-19 <--- GTID在持续变化 LAST_ERROR_NUMBER: 0 LAST_ERROR_MESSAGE: LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00.000000 LAST_QUEUED_TRANSACTION: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1:19 LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000 LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP: 2021-06-04 15:53:55.395605 LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP: 2021-06-04 15:53:55.395630 QUEUEING_TRANSACTION: QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000 QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00.000000 QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00.000000
以及查看复制组各成员的状态:
[root@GreatSQL][(3306)]> select * from performance_schema.replication_group_member_statsG*************************** 1. row *************************** CHANNEL_NAME: group_replication_applier VIEW_ID: 16227931944218245:4 MEMBER_ID: 0fbb2cfd-c4d9-11eb-8747-525400e2078a COUNT_TRANSACTIONS_IN_QUEUE: 0 <--- 等待冲突检测的事务队列大小 COUNT_TRANSACTIONS_CHECKED: 0 COUNT_CONFLICTS_DETECTED: 0 COUNT_TRANSACTIONS_ROWS_VALIDATING: 0 TRANSACTIONS_COMMITTED_ALL_MEMBERS: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa1:1-19 LAST_CONFLICT_FREE_TRANSACTION:COUNT_TRANSACTIONS_REMOTE_IN_APPLIER_QUEUE: 0 <--- 本地等待apply的事务队列大小 COUNT_TRANSACTIONS_REMOTE_APPLIED: 3 COUNT_TRANSACTIONS_LOCAL_PROPOSED: 0 COUNT_TRANSACTIONS_LOCAL_ROLLBACK: 0 ...
5、进一步,再增加一个新节点
如果想对MGR集群扩展读性能,可以增加新的SECONDARY节点。
按照前面的方法,先初始化一个新的实例 mgr04,它运行的端口是 3309。然后利用 clone plugin(主从节点都必须要启用clone plugin) 从现有其他节点复制数据过来,再加入MGR集群。
运行clone复制数据需要 BACKUP_ADMIN
权限(复制源、目标两个节点都需要),前面已经授予了。
首先,设置clone donor节点:
# 尽量从SECONDARY节点复制数据,不从PRIMARY节点复制[root@GreatSQL][(3309)]> set global clone_valid_donor_list='127.0.0.1:3307';
开始复制数据:
[root@GreatSQL][(3309)]> clone instance from repl@127.0.0.1:3307 identified by 'repl';#clone结束后,会自动重启mysqld实例#但因为该实例没有用systemd服务管理起来,所以需要手动启动进程ERROR 3707 (HY000): Restart server failed (mysqld is not managed by supervisor process).
再次启动3309端口实例,登入查询,就能看到从其他节点复制过来的数据了:
[root@GreatSQL][(3309)]> select * from greatsql.t1;+-----+| id |+-----+| 105 || 423 || 557 |+-----+3 rows in set (0.00 sec)
在mgr04实例上启动MGR服务:
[root@GreatSQL][(3309)]> start group_replication;Query OK, 0 rows affected (2.85 sec)[root@GreatSQL][(3309)]> select * from performance_schema.replication_group_members;+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 0fbb2cfd-c4d9-11eb-8747-525400e2078a | greatsql-mgr | 3306 | ONLINE | PRIMARY | 8.0.22 || group_replication_applier | 1778e87a-c4d9-11eb-bf33-525400e2078a | greatsql-mgr | 3307 | ONLINE | SECONDARY | 8.0.22 || group_replication_applier | 1c8ebfa6-c4d9-11eb-80d1-525400e2078a | greatsql-mgr | 3308 | ONLINE | SECONDARY | 8.0.22 || group_replication_applier | bc037d6c-c4de-11eb-a5b8-525400e2078a | greatsql-mgr | 3309 | ONLINE | SECONDARY | 8.0.22 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
可以看到,新节点加入成功了。
6、再进一步,切换主节点
如果需要升级MGR集群中各节点的MySQL版本,则可以进行滚动升级。
即先升级完全部SECONDARY节点,再将PRIMARY节点停掉下线,最后升级,MGR集群会自动选择其他已升级完的节点作为新的PRIMARY节点,等到原来的PRIMARY节点也升级完后再加入 回来即可,这就完成整个集群所有节点的升级工作了。
6.1 先升级SECONDARY节点
现在要升级mgr4节点的MySQL版本,需要先停掉MGR服务:
[root@GreatSQL][(3309)]> stop group_replication;
再停掉mysqld进程后,在my.cnf中增加一行配置:
upgrade=AUTO
替换/指定新的MySQL二进制程序文件(相同大版本,只有相近几个小版本的差异时可以这么做),再次启动mysqld进程,即可实现自动升级。
这是MySQL 8.0.16之后的升级新方法,在8.0.16之前,需要手动执行 mysql_upgrade
二进制程序进行升级。
启动过程中,能看到类似下面的日志:
[System] [MY-013381] [Server] Server upgrade from '80022' to '80025' started.[Note] [MY-013386] [Server] Running queries to upgrade MySQL server.[Note] [MY-013387] [Server] Upgrading system table data.[Note] [MY-013385] [Server] Upgrading the sys schema.
之后再启动MGR服务,就能看到各节点的MySQL版本不同了。
[root@GreatSQL][(3309)]> select * from performance_schema.replication_group_members;+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 0fbb2cfd-c4d9-11eb-8747-525400e2078a | greatsql-mgr | 3306 | ONLINE | PRIMARY | 8.0.22 || group_replication_applier | 1778e87a-c4d9-11eb-bf33-525400e2078a | greatsql-mgr | 3307 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | 1c8ebfa6-c4d9-11eb-80d1-525400e2078a | greatsql-mgr | 3308 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | bc037d6c-c4de-11eb-a5b8-525400e2078a | greatsql-mgr | 3309 | ONLINE | SECONDARY | 8.0.25 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
如上图所示,只剩下mgr01节点还没升级。
从MySQL 8.0.16开始,新增MGR协议要求,比如使用相同的通信协议版本才能组成MGR集群,而8.0.22和8.0.25是相同的,所以可以在同一个集群里。
#在mgr01上执行[root@GreatSQL][(3306)]> select version(), group_replication_get_communication_protocol();+-----------+------------------------------------------------+| version() | group_replication_get_communication_protocol() |+-----------+------------------------------------------------+| 8.0.22-13 | 8.0.16 |+-----------+------------------------------------------------+#在mgr04上执行[root@GreatSQL][(3309)]> select version(), group_replication_get_communication_protocol();+-----------+------------------------------------------------+| version() | group_replication_get_communication_protocol() |+-----------+------------------------------------------------+| 8.0.25 | 8.0.16 |+-----------+------------------------------------------------+
6.2 再升级PRIMARY节点
现在关闭mgr01节点后,剩下的三个节点会完成自动选主:
+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 1778e87a-c4d9-11eb-bf33-525400e2078a | greatsql-mgr | 3307 | ONLINE | PRIMARY | 8.0.25 || group_replication_applier | 1c8ebfa6-c4d9-11eb-80d1-525400e2078a | greatsql-mgr | 3308 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | bc037d6c-c4de-11eb-a5b8-525400e2078a | greatsql-mgr | 3309 | ONLINE | SECONDARY | 8.0.25 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
自动选择了 mgr02 节点作为新的PRIMARY节点(未设定各节点权重值时,则按照 MEMBER_ID
的顺序依次选主)。
待到mgr01节点也完成升级,重新加回集群后:
+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 0fbb2cfd-c4d9-11eb-8747-525400e2078a | greatsql-mgr | 3306 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | 1778e87a-c4d9-11eb-bf33-525400e2078a | greatsql-mgr | 3307 | ONLINE | PRIMARY | 8.0.25 || group_replication_applier | 1c8ebfa6-c4d9-11eb-80d1-525400e2078a | greatsql-mgr | 3308 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | bc037d6c-c4de-11eb-a5b8-525400e2078a | greatsql-mgr | 3309 | ONLINE | SECONDARY | 8.0.25 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
6.3 手动切换PRIMARY节点
此时,还是选择mgr02作为PRIMARY节点,不会发生变化,除非手动执行切主操作:
[root@GreatSQL][(3306)]> select group_replication_set_as_primary('0fbb2cfd-c4d9-11eb-8747-525400e2078a');+--------------------------------------------------------------------------+| group_replication_set_as_primary('0fbb2cfd-c4d9-11eb-8747-525400e2078a') |+--------------------------------------------------------------------------+| Primary server switched to: 0fbb2cfd-c4d9-11eb-8747-525400e2078a |+--------------------------------------------------------------------------+[root@GreatSQL][(3306)]> select * from performance_schema.replication_group_members;+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+| group_replication_applier | 0fbb2cfd-c4d9-11eb-8747-525400e2078a | greatsql-mgr | 3306 | ONLINE | PRIMARY | 8.0.25 || group_replication_applier | 1778e87a-c4d9-11eb-bf33-525400e2078a | greatsql-mgr | 3307 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | 1c8ebfa6-c4d9-11eb-80d1-525400e2078a | greatsql-mgr | 3308 | ONLINE | SECONDARY | 8.0.25 || group_replication_applier | bc037d6c-c4de-11eb-a5b8-525400e2078a | greatsql-mgr | 3309 | ONLINE | SECONDARY | 8.0.25 |+---------------------------+--------------------------------------+--------------+-------------+--------------+-------------+----------------+
这就完成滚动升级以及再次切主的全部操作了。
至此,MGR集群的构建、添加新节点、滚动升级、切主等操作都已完成。
在单机多节点构建MGR集群,和在多机上的构建过程并无本质区别,大家可以自行操作一遍。
Enjoy GreatSQL 🙂