Is arm64 actually supported?

[AndBondStyle]

Tried to run jazzy image on jetson:

$ docker pull --platform linux/arm64 ghcr.io/ros-navigation/nav2_docker:jazzy-1.3.7
...
Digest: sha256:f5d2904ae51d79490381b25243dc18b59bb50d089d3930f5d301b894bf6ad8a6
Status: Downloaded newer image for ghcr.io/ros-navigation/nav2_docker:jazzy-1.3.7
ghcr.io/ros-navigation/nav2_docker:jazzy-1.3.7

$ docker inspect ghcr.io/ros-navigation/nav2_docker:jazzy-1.3.7 | grep -i arch
    "Architecture": "arm64"

$ docker run --rm -it ghcr.io/ros-navigation/nav2_docker:jazzy-1.3.7 bash
exec /ros_entrypoint.sh: exec format error

Here you're using osrf/ros as base image, however osrf/ros does not provide arm64 builds, only /ros does.

I'm sorry if I'm missing something... but is it ok?

[SteveMacenski]

I didn’t explicitly aim to support ARM, but happy to do so if you have a suggested workflow to make that possible. We want to use the osrf/ros images since they’re updated regularly with releases of ROS. The docker ros versions can often be woefully out of date since rebuilds are only triggered when layers below it are updated.

It sounds like the issue is with osrf/ros supporting arm, or finding another base image with arm support.

[AndBondStyle]

I didn’t explicitly aim to support ARM

In that case it's a little confusing to see ARM images in github packages and in CI...

I don't have an ideal workflow but I have some experience with multi-arch/multi-stage/cross-compiling docker builds (mostly for nvidia jetson family), but I'm ready to help. As I understand the main problem is that we don't have an ARM base images, it's really a shame that osrf doesn't provide them (you know, nowadays there are actual ARM-based personal computers, not only SBCs...), so I'm not really sure how to approach this.

[SteveMacenski]

#15 This removes the ARM64 builds, thanks for the note. We shouldn't be building ARM docker images from tonight onward.

For supporting ARM for these docker images, I think the main issues is to have the option of replacing the osrf/ros base image with another image that is compatible with ARM64. I think everything else should just work after that point since we don't do anything special that is architecture specific in our Dockerfile. What docker images do you use now with ARM64?

[AndBondStyle]

Currently using https://hub.docker.com/_/ros/

Also maybe you missed this in #15

[SteveMacenski]

Thanks and also fixed. The problem with those images is that they are not updated with distribution releases and syncs, meaning they’re often out of date and out of step with the binaries. So, I don’t think those are great options. Maybe you can look at the ROS 2 Docker project and see why ARM isn’t currently being built on. It might be as simple as adding in the 2x lines I removed in these PRs to remove ARM builds and no ones asked for it yet.

Otherwise, if there’s a technical reason ARM isn’t supported, that it’s important context for what options we have next.