How to avoid other pods from being scheduled on your node in Kubernetes

Table of Contents

Taints on nodes repel pods. Tolerations on pods let them ignore specific taints. Together they give you control over scheduling.

Taint effects

NoSchedule — pods without a matching toleration won’t be scheduled on the node.
PreferNoSchedule — the scheduler avoids the node but will use it if there’s nowhere else.
NoExecute — pods without a matching toleration are evicted and won’t be rescheduled there.

Applying a taint

kubectl taint nodes node1 type=db:NoSchedule

This prevents any pod from being scheduled on node1 unless it has a toleration for type=db.

Adding a toleration to a pod

apiVersion: v1
kind: Pod
metadata:
  name: db-pod
spec:
  containers:
  - name: db-container
    image: db-image
  tolerations:
  - key: type
    operator: Equal
    value: db
    effect: NoSchedule

The operator can be Equal (key and value must match) or Exists (only the key must match).

Removing a taint

kubectl taint nodes node1 type:NoSchedule-

The trailing - removes the taint.