Node Affinity & Anti-Affinity with Gitlab

Affinity is exposed through values options for the Gitlab. If you want to schedule your pods to deploy on specific nodes you can do that through the nodeSelector and global.antiAffinity values. Additional info is provided below as well to help in configuring this.

It is good to have a basic knowledge of node affinity and available options to you before customizing in this way - the upstream kubernetes documentation has a good walkthrough of this.

Values for Affinity

While you cannot specify full affinity with the Gitlab chart, node selector options are provided which give a simpler way to specify basic affinity. The nodeSelector value under each subchart should be used to specify affinity. The format to include follows what you’d specify at a pod/deployment level for nodeSelector. See the example below for scheduling the pods only to nodes with the label node-type equal to gitlab:

gitlab:
  task-runner:
    nodeSelector:
      node-type: gitlab
  gitlab-exporter:
    nodeSelector:
      node-type: gitlab
  migrations:
    nodeSelector:
      node-type: gitlab
  webservice:
    nodeSelector:
      node-type: gitlab
  sidekiq:
    nodeSelector:
      node-type: gitlab
  gitaly:
    nodeSelector:
      node-type: gitlab
  gitlab-shell:
    nodeSelector:
      node-type: gitlab
registry:
  nodeSelector:
    node-type: gitlab

Values for Anti-Affinity

The global.antiAffinity value can be set to either soft or hard (soft = preferred, hard = required). This value defaults to soft to attempt to distribute replicas across nodes (without requiring it) - and will apply for all subcharts of Gitlab. To set a hard anti-affinity:

global:
  antiAffinity: "hard"