Docker Slaves plugin - how to specify volumes

[Qiang]

hi,

How can I set container options to the Docker slave such as volume settings? I need to mount a host directory to the container.

So far, the only option I can see is to define the slave container image, and side container image as following:

          dockerNode(image: "maven:3.3.3-jdk-8", sideContainers: ["selenium/standalone-firefox"]) 

How do I pass "-v" or "--volumes-from" to the slave container?

Regards,
Qiang

[nicolas de loof]

Hi,

There's no technical limitation to use this option (we actually already support it to allow docker.sock bind mount on a dedicated side container), but our experience is most user use this for bind-mount, which result in permission issues and in most case are just short terms workarounds to introduce bad practices. So we decided *not* to expose this option to end-user.

IIUC your use case (from some private email) some legacy jobs you run rely on a NFS server to host project dependencies. Relying on a bind mount would make your build fragile and non-reproducible. You better should create a project specific docker image, to include those dependencies (assuming you can't update your build script to a modern dependency resolution approach).  

For sure this require some effort to migrate your builds, but I can't consider "legacy bad practice" as a valid use-case :P

[Qiang]

Thank you for posting the response ! I do need to rethink my strategy now. Even though I need to solve legacy problems in a short term , I agree that it does not become a requirement :)

So for moving data between containers , what options can I explore ? And is there instruction to use side containers ? I was not able to find much documentation.

Regards,

Qiang

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[Qiang]

Hi, Nicolas,

One example I can think of:  for maven build, we want to cache the downloaded dependencies so we don't have to download them every time.

So in that case, I was thinking to cache on the host, or a data volume. Any suggestions?

Thanks,

Qiang

On Saturday, October 15, 2016 at 11:59:08 AM UTC-5, Qiang wrote:

Thank you for posting the response ! I do need to rethink my strategy now. Even though I need to solve legacy problems in a short term , I agree that it does not become a requirement :)

So for moving data between containers , what options can I explore ? And is there instruction to use side containers ? I was not able to find much documentation.

Regards,

Qiang

[nicolas de loof]

The whole build agent root directory is managed as a docker volume, and retrieved from previous build, so you can easily benefit such caching if you configure maven to use adequate path for local repository (which should be the case by default, as /home/jenkins is slave root).

We also considered to offer an option to cache some path, comparable to travis-ci approach (based on tar.gz), so typically let end-user configure maven local repository as "cached". Backed could rely on additional volumes for this purpose, but definitively not on bind-mounts :P. This would let us investigate scalability challenge to distribute such a cache, maybe just by relying on docker volume-plugin features (but then relying on proprietary API), or maybe by using jenkins as a volume replication facility, à la TravisCI.

[Archimedes Trajano]

We also considered to offer an option to cache some path, comparable to travis-ci approach (based on tar.gz), so typically let end-user configure maven local repository as "cached". Backed could rely on additional volumes for this purpose, but definitively not on bind-mounts :P. This would let us investigate scalability challenge to distribute such a cache, maybe just by relying on docker volume-plugin features (but then relying on proprietary API), or maybe by using jenkins as a volume replication facility, à la TravisCI.

Is there an example of how to do caching of some folders with docker-slaves-plugin?