Docker Slaves

Use Containers to setup build agents, without any constraint on images you can use.

Objectives

- [✓] use ANY docker image, without any jenkins-specific prerequisite

- [✓] no SSHD inside container, no JNLP port exposed over the Internet

- [✓] compose your build à la docker-compose with a main build container and sidecar containers for test database, selenium browser, etc

- [✓] define container used for the build as a Dockerfile stored in project SCM - aka "continuous delivery as code"

- [✓] support Pipeline

- [✓] rely on docker volumes to offer workspace persistence between builds

- [✓] extensibility for various docker hosting solutions

Configuration

In your jobs, new option let you define your build environment as a combination of Docker images / Dockerfiles 

History

1.0.2

Fix support for Docker host credentials
Add support for docker socket bind mount via a dedicated binding container. This let you run `docker build` from your build container

1.0.1

Plugin has been moved to jenkinsci github organization so we can publish it in public update center

0.5 - proof of concept

This version has been released at DevoxxFrance while we demonstrated the plugin, so people can give it a try and let us know if it was useful

Why ?

Why (yet another) Docker plugin ?

Most plugins around use docker as a lightweight virtual machine, but don't embrace containers paradigm shift and how they impact CI/CD. 

This plugin has been designed as a pure experiment during Docker Global Hack Day. It's under active development. Plugin authors are CloudBees employees, but the plugin isn't a CloudBees product, please consider this as individuals public experiment.

Read more on https://dockins.github.io

http://dockins.github.io

Diagnostic

If something goes wrong (sic), please first run Jenkins master with -Dit.dockins.dockerslaves.spi.DockerDriver.verbose=true . This will dump in build log all docker commands ran by the plugin and help us understand the issue.

Then, ask for assistance on jenkins-users mailing list and/or report a bug on https://issues.jenkins-ci.org

Future

There's many possible improvements / features we'd like to experiment.

• integrate with Pipeline plugin, especially replace DurableTask by a docker based implementation, running docker commands detached (-d) and polling using docker API for execution status. Would need some way to replace the sh step execution
• consider using a java based docker client for Docker API, so we don't rely on running external commands (and related threads usage)
• integrate with docker orchestrators (amazon ECS, Kubernetes, Hyper_ ...) as an alternative backend
• offer isolated Docker host per build, typically relying on docker inside LXD containers.
• Let build use of docker as part of the build (i.e. bind mount docker.sock in build container)
• experiment with docker volume plugins (flocker) for workspace snapshoting and offline browsing of the exact workspace for a specific build.
• experiment pipeline support for volumes
• support docker 1.12 swarm mode JENKINS-38203
• expose docker.sock so build can run `doker build` (aka "inception") JENKINS-37088