[SOLVED] Enable experimental docker features on github workflow images

Issue

We are trying to enable experimental features on the ubuntu-latest image on github workflows, since would like to use squash to reduce image size. However this is not possible as we get the following error:

/home/runner/work/_temp/59d363d1-0231-4d54-bffe-1e3205bf6bf3.sh: line 3: /etc/docker/daemon.json: Permission denied

for the following workflow:

- name: Build, tag, and push TOING image to Amazon ECR
  id: build-image
  env:
    ECR_REGISTRY: ${{ steps.login-ecr.outputs.registry }}
    ECR_REPOSITORY: TOING/TOING/TOING_REPO
    IMAGE_TAG: TOING_TEST
    DOCKER_CLI_EXPERIMENTAL: enabled
  run: |
    #build and push images
    sudo rm -rf /etc/docker/daemon.json
    sudo echo '{"experimental": true}' >> /etc/docker/daemon.json
    sudo systemctl restart docker
    docker build -t $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG -f core/TOING/Dockerfile .
    docker push $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG
    echo "::set-output name=image::$ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG"

We have verified that the daemon.json file is properly updated, and also used sudo for our commands, as shown.

We have also opened an issue on github regarding this, but have no response so far. I would be greatful for any help.

PS: We have tried both "experimental": true and "experimental": "enabled".

Solution

We have verified that the daemon.json file is properly updated

It looks like it's not properly updated, based on your error message:

/home/runner/work/_temp/59d363d1-0231-4d54-bffe-1e3205bf6bf3.sh: line 3: /etc/docker/daemon.json: Permission denied

What's going on here? Well, the sudo command will run the given command as root. But you're doing a shell redirect, which is handled by the shell itself, not by sudo. In other words, you're redirecting the output of sudo.

If you want to write to a file as root then you'll need to actually run a command that writes the file, and then run that using sudo. For example:

echo '{"experimental": true}' | sudo tee -a /etc/docker/daemon.json

Answered By - Edward Thomson

Answer Checked By - Candace Johnson (WPSolving Volunteer)