集群掉电，同事着急直接启动一台作为服务。
预防外一，先把这个1节点作为主节点，单独作为一个集群 leader。
SET GLOBAL wsrep_provider_options='pc.bootstrap=YES';
同步第2个节点，同步过程中1节点无法访问。查看进程等待。
select user,host,time,command,state from information_schema.processlist where state != '' order by 1;
+----------------------+----------------------+--------+---------+------------------------------------------------+
| user | host | time | command | state |
+----------------------+----------------------+--------+---------+------------------------------------------------+
| eXX | XX | 942 | Query | Waiting for global read lock |
| eXX | XX | 803 | Query | Waiting for global read lock |
| eXXXX |X XX | 3 | Query | Opening tables |
| eXXXX | XX | 10 | Query | Opening tables |
| eXXXX | XX | 16 | Query | Opening tables |
········
可以看到，有全局读锁
Waiting for global read lock
检查同步
MariaDB [(none)]> show status like 'wsrep_clu%'; +----------------------------+--------------------------------------+ | Variable_name | Value | +----------------------------+--------------------------------------+ | wsrep_cluster_weight | 2 | | wsrep_cluster_capabilities | | | wsrep_cluster_conf_id | 18446744073709551615 | | wsrep_cluster_size | 2 | | wsrep_cluster_state_uuid | c86db238-d520-11ea-8d9e-ee07c79bb5a5 | | wsrep_cluster_status | Primary | +----------------------------+--------------------------------------+
MariaDB [(none)]> show variables like '%wsrep_clu%';
+-----------------------+---------------------------------------------------------+
| Variable_name | Value |
+-----------------------+---------------------------------------------------------+
| wsrep_cluster_address | gcomm://172.3.3.41:4567,172.3.3.43:4567,172.3.3.42:4567 |
| wsrep_cluster_name | my_wsrep_cluster |
+-----------------------+---------------------------------------------------------+
2 rows in set (0.001 sec)
报错：
一、
Aug 15 22:05:46 Mariadb42 mysqld[49007]: 2020-08-15 22:05:46 0 [Warning] InnoDB: Table mysql/innodb_table_stats has length mismatch in the column name table_name. Please run mysql_upgrade Aug 15 22:05:46 Mariadb42 mysqld[49007]: 2020-08-15 22:05:46 0 [ERROR] InnoDB: Column last_update in table `mysql`.`innodb_table_stats` is INT UNSIGNED NOT NULL but should be BINARY(4) NOT NULL (type mismatch).
由于集群中版本不同，需要升级数据库的相关表结构。
mysql_upgrade -u root -p --force
二、
Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [Note] InnoDB: Completed initialization of buffer pool Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [ERROR] InnoDB: Upgrade after a crash is not supported. This redo log was created before MariaDB 10.2.2. Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [ERROR] InnoDB: Plugin initialization aborted with error Generic error Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [Note] InnoDB: Starting shutdown... Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [ERROR] Plugin 'InnoDB' init function returned error. Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [Note] Plugin 'FEEDBACK' is disabled. Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [ERROR] Unknown/unsupported storage engine: InnoDB Jun 13 15:05:28 localhost.localdomain sh[41841]: 2020-06-13 15:05:28 0 [ERROR] Aborting'
意思是”不支持在崩溃后进行升级。redo日志是用MariaDB 10.2.2之前创建的。”
翻译成人话就是：由于redo log文件是早期版本（10.2.2之前）创建的，我不认识它。
此处注意，因为公司用的是不同版本的mariadb 做的多主集群，需要将ib_logfile* 日志删除后，自启动（注释掉：#wsrep_on ）使其建立自己版本的 ib_logfile0,ib_logfile1 后进行同步，有时无法同步成功，删除grastate.dat, galera.cache, ib_logfile*, ibdata* 后进行同步即可。