By Shaun
I am deploying a container to the App Platform as a web service.
If I deploy a pre-built image, the build is obviously skipped, and the deploy stage fails usually[^1] with:
ERROR failed health checks after 1 attempts with error Readiness probe failed: dial tcp 10.xxx.xxx.xxx:8080: connect: connection refused
If I deploy with a GitHub repo (the same Dockerfile), the build is obviously not skipped, succeeds, and the deploy stage succeeds.
The only thing I am left trying to debug is the externally built image is for the wrong platform, but DO recommends linux/amd64 which is what it is built for.
Repo: https://github.com/freeCodeCamp/exam-creator/tree/4713a42e8ba966307d8ab62986b489bf28cbe13d
[1]: Sometimes the deploy logs fail with just []
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Hey Shaun,
I’ve seen this kind of thing happen before, and in most cases, it’s due to the container not exposing the right port or not listening on the expected interface.
App Platform expects your app to listen on port 8080 by default. If your app is using a different port like 3000, either update the app to use 8080 or set the correct port in the App Platform settings under the “HTTP Port” field.
Also, make sure your app is binding to 0.0.0.0 and not localhost, otherwise, the internal health checks won’t be able to reach it and the deploy will fail with that “connection refused” error.
Since the same Dockerfile works when App Platform builds it from GitHub, the image itself is probably fine. The issue is likely with how the externally built image behaves at runtime, maybe it’s starting too slowly or not binding properly. You can test this locally by running:
docker run -p 8080:8080 your-image
If it doesn’t respond there, it won’t work on App Platform either.
- Bobby
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