[MySQL Cluster fault recovery]

Find the node with offset

Restart the three control nodes at the same time , The database services of the three nodes are abnormal, and the cluster fails , The recovery method is as follows ：
Find the node with offset
cat /var/lib/mysql/grastate.dat

Find the maximum value , First on the node of the vertex galera_new_cluster.
If all node values are -1, stay galera1 Node execution galera_new_cluster.
example ：
The offset values are the same （-1）

So stop the database service at the node first systemctl stop mysql, Pay attention to check whether there is any mysql Process and monitoring , First kill fall mysql All monitors （ If you look at 4567 Port listening netstat -anp|grep 4567）, This step is to avoid the abnormal stop of the database and residual processes .
Re execution #galera_new_cluster

The remaining nodes start mysq service

#systemctl start mariadb.service

#systemctl status mariadb.service

Verification cluster ：

Execute... At any node mysql , Re execution SHOW GLOBAL STATUS LIKE ‘wsrep_%’;
wsrep_incoming_addresses If there are three nodes, the cluster will recover successfully