Upgrade Temporal Server

Excerpt from Temporal’s documentation:

Temporal Server should be upgraded sequentially. That is, if you’re on version (v1.n.x), your next upgrade should be to (v1.n+1.x) or the closest available subsequent version. This sequence should be repeated until your desired version is reached.

1. Upgrade Database Schema: Before initiating the Temporal Server upgrade, use one of the recommended upgrade tools to update your database schema. This ensures it is aligned with the version of Temporal Server you aim to upgrade to.
2. Upgrade Temporal Server: Once the database schema is updated, proceed to upgrade the Temporal Server deployment to the next sequential version.

Also, be aware that each upgrade requires the History Service to load all Shards and update the Shard metadata, so allow approximately 10 minutes on each version for these processes to complete before upgrading to the next version.

The Temporal K8s charms facilitate server upgrades in the following way:

1. The Temporal Admin charm should be updated to the next charm revision that you currently have deployed as follows:

   juju refresh temporal-admin-k8s --revision=<your_revision + 1>
   
   # The schema setup action must be run before updating the Temporal K8s charm
   juju run temporal-admin-k8s/leader setup-schema
   

   This will ensure that your database schema is updated if any updates are available.

2. The Temporal K8s charm should be updated to the next charm revision that you currently have deployed as follows:

   juju refresh temporal-k8s --revision=<your_revision + 1>
   

Warning: It is essential that upgrades are done one consecutive revision at a time. Charmed Temporal K8s can only guarantee backward compatibility between two consecutive revisions in line with the upgrade system adopted by the Temporal Server.

Appendix

The table below shows a mapping between the Temporal K8s charms and the Temporal server versions on the edge channel. It can be used as a reference for upgrading your charm revisions in line with the Temporal server version so as to avoid any breaking changes.