If you’ve used PostgreSQL in Kubernetes with Helm, chance are you’ve locked yourself out after performing an upgrade. The reason for this is that if you do not specify a password explicitly using postgresqlPassword, Helm will rotate this password for you when you run helm upgrade. Not ideal. This has happened to me a few times over the years.

To restore access, you need to to jump in to your PostgreSQL container (kubectl exec -ti your-postgres-container -n your-namespace bash) and temporarily alter the authentication. This of course is not ideal, so we want to move as swiftly as possible.

From within the container, run the following commands:

$ sed -i 's/md5/trust/' /opt/bitnami/postgresql/conf/pg_hba.conf
$ pkill -HUP postgres

This will allow us to access the PostgreSQL server without authentication and reload the config.

Next, login to the PostgreSQL server and set a password:

$ psql -h -U postgres
psql (11.5)
Type "help" for help.

postgres=# ALTER USER postgres WITH PASSWORD 'my-password';
postgres=# \q

Finally, kill the PostgreSQL server, which should automatically terminate your connection:

$ pkill postgres
command terminated with exit code 137

When it comes back, the changes to pg_hba.conf should have been reverted, and you should now be able to access the server using the password you set above.