I'm running a build in Jenkins which is running inside Kubernetes.

When the job starts, a container starts in the cluster and the build runs inside it.

A step in the build requires building an RPM using rpmbuild and for that matter I use this docker image.

So what happens is that when the job starts, it fires up a jenkins slave jnlp dind container with a volume mount of /var/run/docker.sock:/var/run/docker.sock, it then pulls the code from git and running a Makefile to build the code.

When the build process finishes, I want to fire up another container (the one containing rpmbuild), so from within the jnlp dind container I run:

docker run -e WORKSPACE=/home/jenkins/agent/workspace/product-Provisioner-3.17 -e PROV_NAME=product-provisioner -v ${WORKSPACE}:/srv --privileged -t registry/rpmbuild:latest /usr/bin/rpmbuild -v -bb --clean --define '_workspace /srv' /srv/provisioner/SPECS/${PROV_NAME}.spec

But for some reason the volume is not mounted and when I do kubectl exec -it jnlp-container sh, I see that the /srv directory doesn't contain the files in the ${WORKSPACE}.

Running the rpmbuild container just with --help works so the docker inside docker inside docker works, just the volume isn't mounted properly.

As far as I know, running a container from within another container should be doable.

What could be the reason that /srv is not mounted properly?

  • Why not just install rpmbuild in the first container? Jan 20, 2021 at 19:49
  • Because it’s alpine linux
    – Itai Ganot
    Jan 20, 2021 at 22:10
  • Does WORKSPACE exist on the docker host, or just in the first container?
    – Preston Martin
    Mar 11, 2021 at 19:52

1 Answer 1


So this happens to me often and I'm sure there is a better solution, such as using docker volumes but this is what I do.

So first the reason that it doesn't work as expected. Is because we think of the relationship between the first container and the second container being "nested" like this...

k8 -> jenkins -> rpmbuild


Thats what I thought was going on... but its actually like this:

k8 -> jenkins
k8 -> rpmbuild

So they are not "nested", they actually run in parallel to each other side by side.

So when you try to mount a path from inside the jenkins container like /var/jenkins_home/some_workspace/rpmbuild that gets sent back to the docker daemon running on the K8. And it's like... I dont have that path on me.

So what I do on my non-k8 setup, is I mount the jenkins home to someplace like /tmp/jenkins_home/, but dont use tmp this is just an example.

Jenkins = docker run -v /tmp/jenkins_home:/var/jenkins_home

Now when I want to start the rpm container:

rpmbuild = docker run -v /var/jenkins_home/some_workspace/rpmbuild

Now your rpmbuild will have the files like you expected it to. I'm not sure how you will implement this on K8's but what I did was pass the location on the host where I'm mounting the jenkins home directory to the jenkins container as an environment variable like -e DIND_JENKINS_HOME=/tmp/jenkins_home. Then for the pipeline logic to create the path to pass to the rpmbuild container:

    List parts = env.WORKSPACE.split('/workspace/')

    rpmWorkspace= "${env.DIND_JENKINS_HOME}/workspace/${parts[1]}/product-Provisioner-3.17"

Then just start rpmbuild with docker run -v ${rpmWorkspace}:/srv

This took me a long time figure out and it was incredibly frustrating. Googling did not really help. So I hope this clears things up for you and bravo for you coming forward to ask this question.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.