I recently noticed a significant issue: all the contents of every folder that was mounted in my Docker containers seem to have been wiped out overnight. I'm running Debian on an Intel NUC, hosting various local services including Home Assistant and the UniFi controller, and I use Watchtower to manage automatic updates for my containers. Initially, I discovered that my Home Assistant app wasn't responding. When I checked the web app today, it presented me with the initial setup screen, indicating that all my services had lost their data as well. Has anyone ever experienced something like this before? I'm debating whether to quickly restore the volume from a backup or wait to investigate the root cause further.
5 Answers
That happened to me once! The disk where all the data was stored wasn't mounted properly, so Docker generated local files, which turned out empty. Check to make sure your mounts are active.
Avoid relying on Docker's temporary folders. Also, Watchtower sometimes causes issues with unexpected breaking changes, so consider switching to Dockhand for more controlled updates.
It’s likely that your external mounts weren’t detected, which led to Home Assistant creating a new config folder upon startup. Anything set up without the external mount can be volatile and may disappear after a restart, so fixing your mounts should restore everything!
From what you've described, it doesn’t sound like a Docker problem. Docker doesn’t have any mechanisms to erase data from mounted volumes. If something went wrong, it was likely due to an external factor or something running outside of Docker that caused this issue.
I’ve encountered this when a Docker container loses connection to its Ceph mounts. Try removing the volumes and restarting the containers; it often helps in these situations. Also, make sure to check how your volumes are configured.
I think that might be what happened in my case too!