How can I troubleshoot issues failing over to a secondary cluster in my Amazon Aurora global database due to minor version mismatch?

Short description

Although both the primary and secondary clusters are on the same Aurora PostgreSQL-Compatible versions, you might experience version mismatch. This happens because the primary and secondary clusters are running on different patches of the same version. So you aren't able to failover to the secondary cluster in your Amazon Aurora global database, and you get an error similar to this:

Target cluster <DB cluster ID> must be on the same engine version as the current primary cluster.

Resolution

Run the following command to check what versions your primary and secondary Aurora clusters are running:

>> select AURORA_VERSION();

To bring both clusters to the same version, check if there are any pending maintenance actions on the cluster:

>> aws rds describe-pending-maintenance-actions --resource-identifier <ARN of the cluster>

If any pending maintenance action is available, apply the updates required on the cluster.

1. Log in to the Amazon Relational Database Service (Amazon RDS) console.
2. From the navigation pane, choose Databases.
3. Choose the DB cluster that you want to update.
4. For Actions, choose Upgrade Now or Upgrade at Next Window, depending on when you want to apply updates.

For more information, see Applying updates for a DB cluster.

Note: The Aurora version upgrade process causes downtime. It's a best practice to perform the upgrade during your planned maintenance window. After you apply the patch, you can confirm that your primary and secondary Aurora clusters are running the same versions by running this command again:

>> select AURORA_VERSION();

After you have confirmed that both versions of your Amazon Aurora cluster are the same, initiate a manual failover in your Aurora global database.

---

Related information

Using failover in an Amazon Aurora global database

aurora_version