Pipelnes arm worker doesn't seem to work with 32-bit ARM hard-float (linux/arm/v7)

[Stuart Longland]

Hi,

I'm trying to build Docker images for Raspberry Pi 3-based computers running the 32-bit Debian OS (`armhf` architecture), this therefore requires that we use images that are built for the `linux/arm/v7` platform (in Docker parlance).

It's not commercially viable to visit each one and re-load the OS as much as I'd like to do so, we need to support the existing OS that is there.

I tried doing this and got met with an `exec format error`, which is the Linux kernel complaining that it did not understand the binary format.

I've reproduced this in a simple repository which I've published here for discussion (my workplace Bitbucket "work space" does not allow public repositories).

https://bitbucket.org/sjlongland/armv7-testing/src/master/

This repository pulls the base image we use in our builds, then tries to run `node --version` inside the container.  It should print the version of NodeJS downloaded.  A simple "hello world".

I have specified `arch: arm` in the pipeline configuration.  This *should* schedule the work on an ARM worker node, and in my fuller example, I indeed see it pulling `arm64` packages, so I know I configured that part right.

However, when it gets to the point of executing ARMv7 code, it crashes out at that point.

How do I build ARMv7 images on Bitbucket Pipelines?

Regards,

Stuart Longland

[Stuart Longland]

For the records, running one's own runner on a Raspberry Pi with a 64-bit OS, this repository _does_ work… however it doesn't work if I use Atlassian's hosted runners: which was the point of migrating to Pipelines in the first place.

"ARM" is a pretty broad term: it not only covers ARMv8+ which is 64-bit, but also ARMv6/v7 which is 32-bit, ARMv5 which is the original 32-bit soft-float "embedded" ABI; and theoretically covers the original ARM ABI used in the Acorn Archimedes, not to mention odd-balls like big-endian ARM (`armeb`).

Atlassian's documentation is very vague here just calling it "ARM" and not clarifying exactly which ABIs are supported.

So the issue is unresolved: `armv7` images do not work with Pipelines using the infrastructure.  The claimed "ARM" workers, do not appear to support ARMv7.

[Stuart Longland]

Also observed, if you run your own runner, and it’s busy, subsequent builds don’t wait for it to become free: they fail straight away.

Another reason why DIYing runners is undesirable.