I'm tyring to figure out the best strategy for containerizing builds in a Jenkins CI/CD infrastructure using Docker. From what I see I have 2 options:
(1) Use ephemeral slaves that get provisioned on-demand on Docker hosts using the Docker Plugin: https://wiki.jenkins-ci.org/display/JENKINS/Docker+Plugin Once the build completes the slave is disposed. As a consequence, only one build ever gets run on a single slave.
(2) Use static slaves (e.g. VMs) that run builds inside Docker containers using the CloudBees Docker Custom Build Environment Plugin: https://wiki.jenkins-ci.org/display/JENKINS/CloudBees+Docker+Custom+Build+Environment+Plugin As a consequence, multiple (isolated) builds can run on a single slave.
What are the main advantages/disadvantages of one approach over the other? When and why should should I choose one over the other? This does not appear at all obvious to me.
I suspect builds are lighter weight that slaves, so for a CI/CD infrastructure orchestrating a large end-to-end pipeline with many jobs running (2) would be more scalable - each Jenkins slave incurs at least 2 threads on the master node.
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