Kamal with 'multiarch false' setup ends with docker exit status 256 - the image does not exist locally

[abratashov]

I've added this setting to deploy.yml:

builder:
  multiarch: false

When try to set up server, it fails with error An image does not exist locally with the tag: registry.gitlab.com/user/my-app/my-app-demo

Full log:

kamal setup -d demo
 ...

docker build -t registry.gitlab.com/user/my-app/my-app-demo:ac0662f5f2ac4fd0766375c0a601f377acb89962_uncommitted_71a99c5fce56c9d5 -t registry.gitlab.com/user/my-app/my-app-demo:latest --label service="my-app-demo" --file Dockerfile . && docker push registry.gitlab.com/user/my-app/my-app-demo:ac0662f5f2ac4fd0766375c0a601f377acb89962_uncommitted_71a99c5fce56c9d5 && docker push registry.gitlab.com/user/my-app/my-app-demo:latest

#0 building with "kamal-my-app-demo-multiarch" instance using docker-container driver
...
#21 [stage-2 4/4] RUN useradd rails --create-home --shell /bin/bash &&     chown -R rails:rails db log public storage tmp
#21 CACHED
WARNING: No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
The push refers to repository [registry.gitlab.com/user/my-app/my-app-demo]
An image does not exist locally with the tag: registry.gitlab.com/user/my-app/my-app-demo

Finished all in 32.5 seconds
ERROR (SSHKit::Command::Failed): docker exit status: 256
docker stdout: The push refers to repository [registry.gitlab.com/user/my-app/my-app-demo]
docker stderr: #0 building with "kamal-my-app-demo-multiarch" instance using docker-container driver

---

Kamal: 1.4.0 Docker: 24.0.5 Ubuntu: 22.04

[abratashov]

Solved this issue by changes from:

builder:
  multiarch: false

=>

builder:
  cache:
    type: registry
  remote:
    arch: amd64

As result, Kamal runs it with a correct docker command:

docker buildx build --push --platform linux/amd64 --builder kamal-my-app-demo-native-remote -t registry.gitlab.com/user/my-app/my-app-demo:0a2e408b9e77d6e5e4a9c73be0ccd232edf4b6c5_uncommitted_026c0b9acf253cef -t registry.gitlab.com/user/my-app/my-app-demo:latest --cache-to type=registry,ref=registry.gitlab.com/user/my-app/my-app-demo-build-cache --cache-from type=registry,ref=registry.gitlab.com/user/my-app/my-app-demo-build-cache --label service="my-app-demo" --file Dockerfile .

So, I left this ticket open, because as I see multiarch: false doesn't work correctly.

---

CPU architecture: uname -m My machine: x86_64 Host: x86_64

[dhh]

I think something else is at play. I just built a new app using multiarch: false. Seems like maybe it's related to the registry. Feel free to open another ticket if you pin it down further, but I can't replicate it as-is.

[abratashov]

Yes, sure!

P.S. David, thank you for empowering your great dreams! We've just successfully migrated from the hundred Ansible scripts into the few files of Kamal, it works, and it's fantastic!