If your postgres database is only accessible from inside a kubernetes cluster, e.g. if it's configured in AWS RDS and not available to the public (as it should be!), here's how to open a psql shell inside Kubernetes and connect to the database. Make sure to replace the variables appropriately.
$ kubectl run postgresql-client \
--image=postgres \
--namespace=$NAMESPACE \
--stdin=true --tty=true \
--rm=true \
--env="PGPASSWORD=$PASSWORD_FOR_POSTGRES \
--command -- \
psql --host=$HOSTNAME_FOR_POSTGRES --username=$USERNAME_FOR_POSTGRES $DATABASE_FOR_POSTGRES
You need to specify the password as an env variable for the container since you can't answer the password prompt in the container.
If you don't immediately see a postgres shell, wait a few seconds and press enter.
The pod will automatically be deleted when the shell closes.
