Gitlab-Runner 19.2 does not honor platform

GitLab CI/CD
1

Problem to solve

Since I upgraded Gitlab-Runner from 19.1 to 19.2 I get “exec format error” when running commands within a container using a different platform. Does anyone else experience this?

Steps to reproduce

E.g. on amd64 machine, trigger a job with platform for docker image and run a shell command

 image:
    docker:
      platform: linux/arm64

Configuration

See “Steps to reproduce”

Versions

Please select whether options apply, and add the version information.

  • Self-managed
  • GitLab.com SaaS
  • Dedicated
  • Self-hosted Runners

Versions

  • GitLab: 19.2.0
  • GitLab Runner: 19.1.1 (working) / 19.2.0 (issue)
2

Hi @unclej84,

Thanks for reporting this issue.

Given that this started right after upgrading to Runner 19.2 and worked on 19.1.1, it’s very likely a regression in GitLab Runner’s Docker/platform handling rather than something expected.

To get this in front of the Runner team, could you please open a bug in the gitlab-org/gitlab-runner project with these details:

  1. Go to: GitLab.org / gitlab-runner · GitLab
  2. Click Issues → New issue and pick the Bug template.
  3. Include:

  • A minimal .gitlab-ci.yml that reproduces the problem (showing the full image: block with docker: platform: linux/arm64).

  • Your runner config.toml (at least the executor, the [runners.docker] section, and the host OS/architecture – e.g. amd64).

  • Docker version and the output of these commands run directly on the runner host:

    docker info
docker run --platform=linux/arm64 <same-image> uname -m

    bash

  • The job log excerpt from “Preparing the “docker” executor” down to the exec format error.

  • Exact versions: GitLab and GitLab Runner 19.1.1 (working) vs 19.2.0 (failing).

If you can share the issue link back here once it’s created, others hitting the same problem can follow along.

3

After preparing all the steps, I am a bit concerned that it might be something else because

docker run --platform=linux/arm64 ubuntu:24.04 uname -m

also gave me

exec /usr/bin/uname: exec format error

on the host directly.

After some digging, if found that the emulator might be missing, so I ran

docker run --privileged --rm tonistiigi/binfmt --install all

on the runner host and afterwards I got aarch64 as output and also the runner was working again.

So everything fine again but I am still wondering why it was working with runner version 19.1.1 but not 19.2.0.

Ticket can be found here.

4

Hi @unclej84,

Thanks for following up and glad you found the tonistiigi/binfmt workaround and got things running again. Since docker run --platform=linux/arm64 … was also failing directly on the host, it does point to missing binfmt/QEMU rather than a Runner 19.2 regression.

The issue you opened at gitlab-org/gitlab-runner is still useful, though: it clearly shows how 19.2 surfaces this scenario, and gives the Runner team a concrete repro plus a workaround. They might decide to document this better (or add a clearer hint when exec format error happens in a cross-arch platform setup), so thank you for filing it and linking all the details.