400 Bad Request when pushing Docker image to registry.fly.io

Questions / Help
1

I have a C# ASP.NET Core backend with a React frontend that I deploy using a single Docker image on fly.io using registry.fly.io . I’ve already deployed my app in the past many times without issue and the app works great. Yesterday, I tried to push a newly-built image with some code changes to registry.fly.io , but I got this error: “unknown: unexpected status from HEAD request to https://registry.fly.io/v2/movie-info-flyio/manifests/dev: 400 Bad Request”. I tried many times today and yesterday to push the Docker image to the registry and I kept getting the same error. And I am making sure to “fly auth docker” beforehand.

It’s strange, because I haven’t changed anything about my app’s infrastructure, including how I build and push to registry.fly.io . Not only that, but the GitHub Actions pipeline I set up to automatically deploy to that same dev environment that also worked previously with no issue has the exact same error, so I know it’s not a local setup problem.

Any ideas what might be causing this error? It doesn’t seem to be a widespread problem or I’d see other threads here about it. But I honestly don’t know why the “docker push” command would be failing in this way.

2

Hm… Are you perhaps trying to reuse the dev tag? That’s broken in the past, and it’s not completely clear whether Fly.io considers it a supported feature.

(Their examples of --image-label in the official docs suggest that they’re thinking of it as being a fresh tag with each new push.)

The registry is multi-layered, distributed setup these days, so there may be implementation concerns about who still sees the old version of a reused tag, and the like, :thinking:…

(A standard of unique tags, in contrast, creates a monotone system, which is much easier to make distributed.)

3

Thanks @mayailurus, I think that’s my problem. After changing the tag, it seems to deploy just fine. I’d change the tag each time, but my GitHub Actions expect a certain tag. Maybe there’s a way to fix that in my automated push and deploy setup, but I guess for now I’ll just add a digit to the end of my tag (like “dev2”) and hope this doesn’t crop up very often in future.