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diff --git a/src/health/guides/mysql/mysql_galera_cluster_state_crit.md b/src/health/guides/mysql/mysql_galera_cluster_state_crit.md new file mode 100644 index 000000000..c1ac649e5 --- /dev/null +++ b/src/health/guides/mysql/mysql_galera_cluster_state_crit.md @@ -0,0 +1,46 @@ +### Understand the alert + +The `mysql_galera_cluster_state_crit` alert is triggered when the Galera node state is either `Undefined`, `Joining`, or `Error`. This indicates that there is an issue with a Galera node in your MySQL Galera Cluster. + +### What is a MySQL Galera Cluster? + +MySQL Galera Cluster is a synchronous, multi-master database cluster that provides high availability, no data loss, and scalability for your MySQL databases. It uses Galera replication library and MySQL server to achieve these goals. + +### Troubleshoot the alert + +To troubleshoot the MySQL Galera Cluster State Critical alert, follow these steps: + +1. Inspect the MariaDB error log + + Check the MariaDB error log for any relevant error messages that can help identify the issue. + + ``` + sudo tail -f /var/log/mysql/error.log + ``` + +2. Check the Galera node's status + + Connect to the problematic MySQL node and check the Galera node status by running the following query: + + ``` + SHOW STATUS LIKE 'wsrep_%'; + ``` + + Take note of the value of `wsrep_local_state` and `wsrep_local_state_comment`. + +3. Diagnose the issue + + - If `wsrep_local_state` is 0 (`Undefined`), it means the node is not part of any cluster. + - If `wsrep_local_state` is 1 (`Joining`), it means the node is trying to connect or reconnect to the cluster. + - If `wsrep_local_state` is 5 (`Error`), it means the node has encountered a consistency error. + +4. Resolve the issue + + - For an `Undefined` state, check and fix the wsrep configuration settings and restart the node. + - For a `Joining` state, ensure that the node can communicate with the other nodes in the cluster and make sure that the cluster's state is healthy. Then, retry joining the node to the cluster. + - For an `Error` state, the node may need to be resynchronized with the cluster. Restart the mysqld process on the affected node, or you may need to perform a full state transfer to recover. + +5. Monitor the cluster + + After resolving the issue, monitor the cluster to ensure that all nodes are healthy and remain in-sync. + |