How to create slave jenkins given master jenkins?

Question

Below code snippet, taken from here creates master jenkins that runs in a container:

# Create Docker Group with GID
# Set default value of 497 if DOCKER_GID set to blank string by Docker Compose
RUN groupadd -g ${DOCKER_GID:-497} docker

# Used to control Docker and Docker Compose versions installed
# NOTE: As of February 2016, AWS Linux ECS only supports Docker 1.9.1
ARG DOCKER_ENGINE=1.10.2
ARG DOCKER_COMPOSE=1.6.2

# ......

# Install Docker Engine
RUN apt-key adv --keyserver hkp://pgp.mit.edu:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D && \
    echo "deb https://apt.dockerproject.org/repo ubuntu-trusty main" | tee /etc/apt/sources.list.d/docker.list && \
    apt-get update -y && \
    apt-get purge lxc-docker* -y && \
    apt-get install docker-engine=${DOCKER_ENGINE:-1.10.2}-0~trusty -y && \
    usermod -aG docker jenkins && \
    usermod -aG users jenkins

---

Above container is dind that launches task(each container) on single EC2 host.

---

To regulate load across multiple EC2 host and launch slave jenkins instance(on each).

We would like to have master jenkins generate build_id for each build that can run on two slave jenkins instances.

To have master & slave jenkins run within each container, across EC2 hosts.

How to approach on making slave container and take build_id from master jenkins?

Answer 1

You could use the EC2 plugin or the ECS plugin if you want to provision agents dynamically. These would provide some environment variables to use when constructing build_id - e.g. :

• BUILD_TAG:

  String of "jenkins-${JOB_NAME}-${BUILD_NUMBER}". All forward slashes ("/") in the JOB_NAME are replaced with dashes ("-"). Convenient to put into a resource file, a jar file, etc for easier identification.

• NODE_NAME:

  Name of the agent if the build is on an agent, or "master" if run on master

You would have to configure the clouds in Jenkins, assign a label to the templates you want to use as agents, and then request those in your pipeline or job configuration.