Kubernetes Taint Command

Introduction

In this lab, you will learn how to use the kubectl taint command, which is a powerful tool in Kubernetes for adding, modifying, and removing taints on nodes. Taints are used to indicate that a node has certain restrictions or requirements, and this can help control the scheduling of pods in a Kubernetes cluster.

Skills Graph

Add a Taint to a Node

In this step, you will learn how to add a taint to a node using the kubectl taint command. Taints are used to mark a node with certain restrictions or requirements, which can affect the scheduling of pods on that node.

To add a taint to a node, you can use the following command:

kubectl taint nodes minikube app=prod:NoSchedule

This will add a taint with key app and value prod to a node named minikube, with the effect NoSchedule. This will prevent pods from being scheduled on the node unless they tolerate the taint.

Then you can view the taints that are currently applied to nodes in your Kubernetes cluster using the kubectl describe node command.

To view the taints on a node, you can use the following command:

kubectl describe node minikube

The taints applied to the node will be listed under the "Taints" section in the output. You can use this information to verify that the taint you added in the previous step is applied to the node.

Remove a Taint From a Node

In this step, you will learn how to remove a taint from a node using the kubectl taint command. This can be useful if you need to update the restrictions or requirements of a node, or if you want to allow pods to be scheduled on a previously tainted node.

To remove a taint from a node, you can use the following command:

kubectl taint nodes minikube app-

It will remove the app=prod:NoSchedule taint from the minikube node. This will allow pods to be scheduled on the node without needing to tolerate the previously applied taint.

Modify a Taint on a Node

In this step, you will learn how to modify a taint on a node using the kubectl taint command. This can be useful if you need to update the restrictions or requirements of a node, but want to retain the existing taint key and effect.

1. Add a new taint with the following content:

kubectl taint nodes minikube app=uat:NoSchedule

2. Use overwrite to force updates

kubectl taint nodes minikube app=dev:NoSchedule --overwrite=true

It will update the app taint value from prod to dev on the minikube node. This will update the taint on the node while retaining the same taint key and effect.

Summary

In this lab, you learned how to use the kubectl taintcommand in Kubernetes. You started by adding a taint to a node using thekubectl taintcommand with a specific key, value, and effect. You then learned how to view the taints applied to a node using thekubectl describe node command.