Docker image updates

Published on 2/8/2021 by Mark Waite

    Beginning with Jenkins 2.279 and Jenkins 2.263.4, the Jenkins project is upgrading the base operating system and Java version used in the jenkins/jenkins:latest and jenkins/jenkins:lts images. The update replaces OpenJDK 8u242 with AdoptOpenJDK 8u282 and replaces Debian 9 ("Stretch") with Debian 10 ("Buster").

    Jenkins and Docker

    Why?

    We’re changing the base image so that we have a better supported operating system and a more current Java release for Jenkins controllers.

    Better supported operating system

    The Docker images provided by the Jenkins project rely on the operating system security processes of the operating system provider.

    Our Docker images have used Debian 9 ("Stretch") for multiple years. Debian 9 security updates have been discontinued as of July 6, 2020. Debian 9 Long Term Support security updates will be discontinued at the end of June 2022. The upgrade to Debian 10 keeps us on an operating system maintained by the operating system security team.

    More current Java release

    The Debian 9 Docker images were based on the openjdk:8-jdk-stretch Docker image. The last update to that image was one year ago with the release of JDK 8u242. We need a maintained Docker base image that keeps pace with JDK releases and operating system updates so that the controller is running the most recent Java updates and most recent operating system updates.

    Other Jenkins controller images have already switched from using openjdk base images to instead use base images provided by Eclipse Adoptium. Eclipse Adoptium is the Eclipse project formed when AdoptOpenJDK joined the Eclipse Foundation. This change adapts the jenkins/jenkins:latest and jenkins/jenkins:lts images to use the Adoptium JDK images in the same pattern as is already used for the Jenkins JDK 11 Docker images like jenkins/jenkins:lts-jdk11. The Jenkins Platform SIG has enjoyed very good results in our interactions with the Eclipse Adoptium project. We look forward to continuing our collaboration with them.

    Thanks a lot to Alex Earl and Jim Crowley for the image build restructuring groundwork that made the image upgrade possible! Also thanks to Oleg Nenashev and other contributors for their reviews and testing.

    Packaging changes

    The Jenkins Docker image based on Debian 10 ("Buster") includes some different packages than Debian 9 ("Stretch"). Some packages have been removed because they are no longer supported by their communities. Some packages have been removed due to infrequent and decreasing use. Users of the Jenkins Docker images may need to extend their definition of their Docker image to include packages that are no longer included in the base image.

    SCM packages removed

    The following source control management packages are no longer included in the Jenkins controller images for jenkins/jenkins:latest or for jenkins/jenkins:lts:

    • bzr

    • mercurial

    • subversion

    Other packages removed

    Additional packages that are no longer included in the Jenkins controller images include:

    • bzip2

    • mime-support

    • python (the Python project stopped supporting Python 2 January 1, 2020)

    • xz-utils

    A detailed list of the exact package changes is available in the pull request.

    Upgrade and compatibility notes

    The Jenkins controller images are designed to be extended to meet user needs. Custom Jenkins controller images can be created from the base images and are designed to allow additional Jenkins plugins and additional operating system packages.

    For example, the Installing Docker instructions illustrate a technique to install the Blue Ocean plugins and some operating system packages in a custom Docker image.

    Docker image with Subversion

    The following Docker image definition installs the most recent Jenkins Long Term Support release with the subversion plugin and the operating system subversion command:

    FROM jenkins/jenkins:lts
USER root
RUN apt-get update && \
    apt-get install -y --no-install-recommends subversion
USER jenkins
RUN jenkins-plugin-cli --plugins subversion:2.14.0

    Build a new docker image from this Dockerfile and assign the image a meaningful name, e.g. "myjenkins-subversion:1.1":

    docker build -t myjenkins-subversion:1.1 .

    Docker image with Mercurial

    The following Docker image definition installs the most recent Jenkins Weekly release with the mercurial plugin and the operating system hg command:

    FROM jenkins/jenkins:latest
USER root
RUN apt-get update && \
    apt-get install -y --no-install-recommends mercurial
USER jenkins
RUN jenkins-plugin-cli --plugins mercurial:2.12

    Build a new docker image from this Dockerfile and assign the image a meaningful name, e.g. "myjenkins-mercurial:1.1":

    docker build -t myjenkins-mercurial:1.1 .

    What’s next?

    We will continue Docker image updates as new Java versions are released.

    If you are interested in new features in Jenkins Docker packaging, stay tuned for future announcements! There are multiple ongoing initiatives which you can find on the public Jenkins roadmap. Some stories:

    • Switching to AdoptOpenJDK.

    • General availability of Windows images.

    • Support for more platforms (AArch64, IBM s390x, PowerPC).

    • Introducing multi-platform Docker images.

    If you are interested in any of these projects and would like to contribute, please reach out to the Platform Special Interest Group which coordinates initiatives related to Jenkins in Docker.

    About the Author
    Mark Waite
    		Mark Waite

    Mark is the Jenkins Documentation Officer, a long-time Jenkins user and contributor, and maintains the git plugin and the git client plugin. He is active in Jenkins special interest groups including the Docs SIG, Platform SIG, and Advocacy SIG.