Info The vanishing container

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Info The vanishing container

DS418play, DS213j, DS3621+, DSM 7.0.4-11091
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I learned something new today. Maybe it will help someone else... or maybe not... I had a stopped container that apparently had a port conflict which I was unaware of. When I started the container, it failed to start. So, not giving it much thought, I cleared the container. In the past, this had no ill effects. But this time, I got a pop-up saying there was a port conflict.

OK... that should be an easy fix... right? But the container vanished after I acknowledged the warning. Not seeing the container under the Synology Docker or Portainer container, I launched the image for the missing container... that created a new container, but my container settings were absent. Finally, I deleted this new container and pulled up my config backup (fixing the port conflict before restoring). Relief!

Is it normal for a container to self-destruct over a port conflict when the "clear" function is initiated? And why?
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Clear does not exist in the Docker world. It is a convenience feature introduced by Synology :)

On Linux in general it is possible to create (not run!) a new container that binds a host port that is already bound by another running container. Though, if you create it with docker run (=create+start) it fails to be created due to port conflict. If the old container was stopped before, then a port conflict is not possible.

Maybe a race condition? The process should be something like "stop old container, create a new container whith old container params using the latest image (as in newest, not necessarily the latest tag) , remove old container, start new container".

I am quite sure that you did find another bug in Synology's wonderful Docker re-distribution.

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