Upgrading PostgreSQL in Kubernetes

I have been running an instance of bitnami’s version of Postgresql 12 for a while, and I have recently upgraded/migrated data from version 12 to 15.

This post doesn’t cover in-place upgrades; instead, it will require you to spin a newer container version.

Deploy New Container Image #

The first step is to deploy a new Postgres container using the updated image version.

This container MUST NOT mount the same volume as the older Postgres container.

Instead, it will need to mount a new volume for the database. The new Postgres server will fail if you mount the older Postgres server volume. This is because Postgres requires the data to be migrated before it can load it.

Backup #

Install the PostgreSQL command line tool on your local machine

brew install PostgreSQL

Start Kubernetes port-forward for postgres service to expose the port on the local system to perform a data dump

kubectl port-forward svc/postgresql-kube 5432 &

Run pg_dumpall, a utility for writing out (dumping) all of your PostgreSQL databases of a cluster

pg_dumpall -h 127.0.0.1 -p 5432 -U postgres -W -f database.sql

If everything goes successfully, a new file is created on the local filesystem.

Import #

We’ll use the Kubernetes copy(cp) command to transfer the dump file into the container.

kubectl cp database.sql postgresql-0:/tmp/database.sql

Open a terminal shell on the new postgresql container.

kubectl exec -it postgresql-0 bash

Finally, import the databases.

I have no name!@postgresql-0:/$ psql -U postgres -W -f /tmp/database.sql

Verify the import and stop the old container. You have completed the upgrade successfully now. Congrats!