Demo Creating node taints on a GKE cluster

In this tutorial, you’ll learn how to control pod placement in Google Kubernetes Engine (GKE) by applying node taints and tolerations. We’ll cover:

1. Creating a GKE cluster with a tainted default node pool
2. Adding an untainted node pool
3. Updating node pool taints post‐creation
4. Provisioning a dedicated node pool with a unique taint
5. Deploying pods with and without tolerations to observe scheduling behavior
6. Removing a taint and watching pods land on the default pool

Prerequisites

• Google Cloud SDK installed or access to Cloud Shell.
• Authentication configured (gcloud auth login).

Set your project and compute zone:

gcloud config set project YOUR_PROJECT_ID
gcloud config set compute/zone us-west1-a

Node Pools & Taints Overview

1. Create a Cluster with a Tainted Default Node Pool

gcloud container clusters create gke-deep-dive \
  --num-nodes=1 \
  --disk-type=pd-standard \
  --disk-size=10 \
  --node-taints=function=research:PreferNoSchedule

Verify the Taint

kubectl get nodes
kubectl describe node <NODE_NAME> | grep -A1 "Taints"

Expected output:

Taints:
  function=research:PreferNoSchedule

2. Add an Untainted Node Pool

New node pools inherit no taints by default. Create one:

gcloud container node-pools create gke-deep-dive-pool \
  --cluster=gke-deep-dive \
  --num-nodes=1 \
  --disk-type=pd-standard \
  --disk-size=10

Verify:

kubectl get nodes
kubectl describe node <NEW_NODE_NAME> | grep -A1 "Taints"

Expected:

Taints: <none>

3. Update a Node Pool’s Taint

Apply a new taint to the existing pool:

gcloud beta container node-pools update gke-deep-dive-pool \
  --cluster=gke-deep-dive \
  --node-taints=function=shared:NoSchedule

Verify:

kubectl describe node <NEW_NODE_NAME> | grep -A1 "Taints"

Expected:

Taints:
  function=shared:NoSchedule

4. Create a Dedicated Node Pool with a Different Taint

Provision a third pool for development workloads:

gcloud container node-pools create gke-deep-dive-pool-dedicated \
  --cluster=gke-deep-dive \
  --num-nodes=1 \
  --disk-type=pd-standard \
  --disk-size=10 \
  --node-taints=dedicated=dev:NoExecute

5. Deploy a Pod That Tolerates the Shared Taint

Save as shared-pod.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: shared-pod
spec:
  containers:
  - name: nginx
    image: nginx
  tolerations:
  - key: "function"
    operator: "Equal"
    value: "shared"
    effect: "NoSchedule"

Apply and inspect scheduling:

kubectl apply -f shared-pod.yaml
kubectl get pods -o wide

The pod should land on the node with function=shared:NoSchedule.

6. Remove the Taint from the Default Node Pool

First, identify the default node:

kubectl get nodes

Then remove its taint:

kubectl taint nodes <DEFAULT_NODE_NAME> function-

Verify:

kubectl describe node <DEFAULT_NODE_NAME> | grep -A1 "Taints"

Expected:

Taints: <none>

7. Deploy a Pod Without Any Toleration

Save as dedicated-pod.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: dedicated-pod
spec:
  containers:
  - name: nginx
    image: nginx

Apply and observe:

kubectl apply -f dedicated-pod.yaml
kubectl get pods

Since the default pool is now untainted, dedicated-pod transitions from Pending to Running on the default node.

Congratulations! You’ve successfully used node taints and tolerations to control pod placement in a GKE cluster.

Links and References

• GKE Taints and Tolerations
• Kubernetes Scheduling Concepts
• kubectl Cheat Sheet