postgresql-container | PostgreSQL container images based on Red Hat Software | Continuous Deployment library

I had the exact same problem a few month ago. The key aspect is that a container can have only one main process defined by the ENTRYPOINT and/or CMD in your Dockerfile.

You cannot just swap out postgres with crond otherwise your database isn't running. It is generally recommended to separate areas of concern by using one service per container.

With that in mind either use a separate container which runs nothing but crond and thus Docker can both track its lifecycle, and restart it when/if it fails, the machine restarts, etc.

Or run the jobs via cron on your host using docker exec.

The third and in my opinion best (but also advanced) solution is pg_cron. It is an postgres extension and therefore runs the jobs in the same database container. Your challenge would be to adapt the configuration and installation of it.

The easy part should be the postgresql.conf:

It looks like this is not trivial, as it requires to set Volume Security Context so all the containers in the pod are run as a certain user https://docs.openshift.com/enterprise/3.1/install_config/persistent_storage/pod_security_context.html

In the Kubernetes projects, this is something that is still under discussion https://github.com/kubernetes/kubernetes/issues/2630, but seems that you may have to use Security Contexts and PodSecurityPolicies in order to make it work.

I think the easiest option (without using the above) would be to use a container entrypoint that, before actually executing PostgreSQL, it chowns the files to the proper user (postgres in this case).