Testing an Intel and Arm multi-architecture Docker image on CircleCI

This is the fourth article about my adventures trying to use my Apple M1 MacBook for development. In the previous article, I described how to configure a CircleCI-based CI/CD pipeline to build a multi-architecture image and push it to a remote repository. The image supports both Intel and ARM architectures. However, the pipeline only tests the image on Intel. In this article, I describe how to configure the pipeline to also test the Docker image on other architectures.

The other articles in this series are:

Configuring the pipeline to test on Arm

By default, CircleCI jobs run on an Intel platform. However, CirclCI also supports the ARM platform. You can create an Arm-based job as follows:

test-arm64:
  machine:
    image: ubuntu-2004:202101-01
    resource_class: arm.medium

The resource_class attribute specifies the ARM resource.

We can configure the pipeline to execute the test-arm64 job after the build job with the following workflow configuration:

workflows:
  version: 2.1
  build-test-and-deploy:
    jobs:
      - build
      - test-arm64:
          requires:
            - build

Extracting a test script from `build-and-test-multi-arch-circleci.sh`

The testing logic needed by the test-arm64 job is currently embedded within build-and-test-multi-arch-circleci.sh. The solution is to split that script into two: build-and-push-multi-arch-circleci.sh and test-multi-arch-circleci.sh. The build job runs both of these scripts. The test-arm64 job runs just the test script:

test-arm64:
  machine:
    image: ubuntu-2004:202101-01
    resource_class: arm.medium
  working_directory: ~/plantuml
  steps:
    - checkout
    - run: ./test-multi-arch-circleci.sh

After making these changes the CircleCI pipeline performs the following steps:

Builds, pushes and tests (on Intel) the multi-architecture image
Builds, tests and pushes the original Docker image
Tests the multi-architecture image on Arm

We are now one step closer to a complete pipeline that builds, tests and publishes a multi-architecture Docker image. In the next article, I reconfigure the pipeline to eliminate the original single architecture image and publish the tested multi-architecture image to Docker Hub.