Adding upstream version 1.44.3.upstream/1.44.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/health/guides/mysql/mysql_galera_cluster_state_crit.md b/health/guides/mysql/mysql_galera_cluster_state_crit.md
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+### 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.
+