This is exactly the problem here, just run Postgres on the host means that you have a hybrid setup, some of your services dockerized the rest are not. This is not appealing to some people. There are other services mostly in the heavy disk IO space that is not easy to move to Docker. It might be worth to call these out in the documents and save some time to sysadmins figuring this out the hard way. If you want to dockerize your application like a REST api or a simple Java app, that works perfectly and the advantages are obviously there though.