Currently, it is possible to link a container to an already running container, so if the linked container has to restart — all its dependencies have to restart.

Consider the following setup with four containers:

• db
• app1, links to db
• app2, links to db
• frontend, links to app1 and app2

They have to be started in order: db, app1, app2, frontend.

Now, I want to update the app1, so I turn it down. It's still displayed as a link in docker ps for frontend (see also #3154).

When time comes, I start a new app1, but at this point I somehow need to tell frontend where is the new one app1. The simple way to do that is restarting frontend as well, but that might interrupt connectivity to app2.

There should be a way to interlink existing containers.