How to deploy container to subset of worker nodes in a docker swarm using affinity?

Question

I have a docker swarm with 1 master node and 7 worker nodes across 3 machines all running tomcat containers.

I wish to deploy all my containers to only strictly 2 worker nodes.

How will i setup the affinity rule for such a deployment?

Can you please help me with the detailed steps on how to achieve this?

score 1 · Accepted Answer · answered Sep 01 '20 at 07:49

1

You can tag the 2 worker nodes:

docker node update --label-add foo=bar node-1
docker node update --label-add foo=bar node-2

and then use deploy placement constraints to force the container land on the nodes that you labeled in the previous step:

services:
  your-service:
    image: your-image
    deploy:
      placement:
        constraints: [node.labels.foo=bar ]

answered Sep 01 '20 at 07:49

Neo Anderson

Can you propose similar solution using `swarm affinity`? @Neo Anderson – mohtashim Sep 01 '20 at 12:57
I am not sure if this can be natively achieved. The documentation is very scarce on `swarm affinity`. – Neo Anderson Sep 01 '20 at 14:44

1 Answers1