Forcing Pods To Run On A Particular Node in OpenShift 3.11

In this post,we’ll see how we can force a pod to run on a particualt node in OpenShift 3.11.

Step 1: Add a taint to the node where you want your pods to be running.

oc adm taint nodes <nodename> app=latest:NoSchedule

Step 2: Add a label to the node where you want your pods to be running.

oc label nodes <nodename> app=latest

Step 3: Now go to the project and edit the DeploymentConfig to use taints and node affinity.

oc project <project_name>

oc edit dc <dc_name>

Now under spec.template.spec section, add following lines

affinity:
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
      nodeSelectorTerms:
      - matchExpressions:
        - key: app
          operator: In
          values:
          - latest
tolerations:
  - effect: NoSchedule
    key: app
    operator: Equal
    value: latest

Now check your pods using oc get pods -o wide -w command and you’ll see that your pods are getting created under designated node.