Using docker-swarm with Jenkins

Question

I have a cluster which is being used as a docker swarm - 1 manager, and 4 workers. The manager node is a pure manager node, set via

docker node update --availability drain <manager-id>

The manager has the /usr/lib/systemd/system/docker.service set to start with

ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0.0:2375 --containerd=/run/containerd/containerd.sock

Now I am trying to use this cluster/swarm as a Jenkins cloud provider, so that all jobs run in docker containers in this swarm. In Jenkins, under Configure Clouds, I have create a cloud provider of type "docker", and provided the manager IP address as the docker host uri, eg. tcp://a.b.c.d:2375. There is no error, but when I start a job, it creates a container on the manager itself.

How can I make it so that each container is deployed on a non-manager container?

Answer 1

Docker Swarm is a layer over Docker and it manages the creation of containers on nodes given docker service definitions.

As I understand it, Jenkins does not know docker swarm, and simply asks the target node to create containers. Docker swarm, and its orchestration is consequently not involved - everything gets created and scheduled on the target node only.