With Google Cloud Build, how do I run a Makefile that executes docker and kubectl commands?

Question

I received a project that is built with a number of Makefiles which run a number of docker commands. I want to build it on Cloud Build.

I know that Cloud Build handles Docker natively, but must work with the existing Makefile-structure.

I tried the make Custom Build step, but Cloud Build failed on lack of docker and kubectl. So I could add these to the Dockerfile of the make Custom Build step, but it seems like that is wrong, because then make runs Docker-in-Docker and this causes problems -- for example, gcloud and kubectl permissions and context are missing.

As a small part of one such a Makefile, here is a target that calls docker build and docker push.

build/myapp/deployer: ...

    docker build \
        --build-arg REGISTRY="$(REGISTRY)/myapp" \
        --tag "$(APP_DEPLOYER_IMAGE)" \
        -f deployer/Dockerfile \
        .

    docker push "$(APP_DEPLOYER_IMAGE)"
    @touch "$@"

How do I run these Makefiles in Cloud Build?

Right, the make just runs some commands, mostly docker build and docker push. However.the make has a complex dependency structure, so I would rather keep it — Joshua Fox, Nov 28 '19 at 09:38
And you did achieve a custom builder with Docker Gcloud and kubectl in it? — guillaume blaquiere, Nov 28 '19 at 15:08
Yes. I built such an image, though I'm not sure that's the right way to go. In fact, even the base Cloud Build image has make and docker — Joshua Fox, Nov 28 '19 at 16:33
Base Cloud Builder image are made for 1 specific things. You want to build or push with docker use the docker image, want to use gcloud, une gcloud image, same thing with kubectl,... Either you explode your make, or you use it with an "do it all" image. — guillaume blaquiere, Nov 28 '19 at 20:26
The deeper question is how to run docker inside a docker container. This is doable, and in fact the Cloud Build default docker-building image does that, but can be problematic, as in the example I am giving here of a 'make' process. — Joshua Fox, Nov 28 '19 at 21:49

score 3 · Accepted Answer · answered Nov 29 '19 at 12:02

3

To answer to your comment: "How to run docker inside a docker container?", you have to see your custom cloud builder like an runner. You can use it like this in Cloud Build

- steps:
  - name: gcr.io/your-project/your-custom-builder
    entrypoint: "bash"
    args: 
      - "-c"
      - |
        Makefile
        <All the script lines that you want which use binaries installed in your custom builder>

Here the custom Cloud Builder run the command but the result is stored in your Cloud Build workspace, not in the custom Cloud Builder container.

answered Nov 29 '19 at 12:02

guillaume blaquiere

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Docker-in-docker makes things complicated. For example, docker/kubectl do not come preconfigured with the suitable service user. Further, they run into problems accessing the filesystem. – Joshua Fox Nov 30 '19 at 16:24
guillaume blaquiere: Perhaps this is the better question: How can we use parameters calculated within the Cloud Build process: https://stackoverflow.com/questions/59118037/h – Joshua Fox Nov 30 '19 at 16:27

With Google Cloud Build, how do I run a Makefile that executes docker and kubectl commands?

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