HedgeDoc + Watchtower

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1

I run HedgeDoc using the official container quay.io/hedgedoc/hedgedoc:latest. Today this image got updated to v1.9.4 automatically by Watchtower. Afterwards the error below was shown in the Docker logs and the container kept restarting:

hedgedoc-app-1       | exec /usr/local/bin/docker-entrypoint.sh: no such file or directory

So I manually replaced image tag latest to 1.9.3 in docker-compose.yml and restarted, and the container came up normally. Then again I replaced the tag to 1.9.4 in docker-compose.yml and did docker compose down && docker-compose up -d and this time the new container came up normally as well.

So somehow the restart by Watchtower did something differently.

Watchtower will pull down your new image, gracefully shut down your existing container and restart it with the same options that were used when it was deployed initially

I am uncertain what “gracefully shut down” means here, probably something else than docker compose down && docker-compose up -d. It also might mean that some migration process did not work as it should have.

Has anyone else seen this? Is this rather a Hedgedoc or a Watchtower thing? I am only running Watchtower for about two months, but my experiences with it automatically updating all kinds of images is very positive so far. Unfortunately I do not remember whether it caused problems when Hedgedoc v1.9.3 came out.

2

Unfortunately, I cannot think of an explanation for your experience or even how you might investigate it (other than deploying a separate dev instance of 1.9.3 and then letting the same Watchtower-driven update occur). I am more curious about Watchtower itself. Currently I use Keel for this purpose. Do you know how that compares to Watchtower?

3

Nope, never heard of Keel before. Looks like this is a K8S equivalent for Watchtower.

I will probably wait for the next HedgeDoc image release to check whether my observation is reproducible.