Node Affinity in Kubernetes Cluster

Question : The Nautilus DevOps team is doing some testing around the Kubernetes cluster for pods, deployments etc. A new ticket has been raised by one of the developer with some particular requirements. Find below more details and perform the task accordingly.

Create a label for node node01 color=grey,

Based on the new label created for node01 using nodeAffinity matchExpressions create a new deployment named grey, use image nginx with latest tag only and remember to mention tag i.e nginx:latest and 3 replicas; ensure container name is nginx-container and that it gets placed on the node01 node only. Also make sure all pods are in running state before clicking on FINISH.

Note: The kubectl utility on jump_host has been configured to work with the kubernetes cluster.

Please Note :-  Perform the below commands based on your question  server,  user name & other details might differ . So please read task carefully before executing. All the Best 👍

Solution:  

1. At first  kubectl  utility configure and working from jump server, run below commands   

thor@jump_host /$ kubectl get deploy No resources found in default namespace. thor@jump_host /$ thor@jump_host /$ kubectl get nodes --show-labels NAME           STATUS   ROLES    AGE     VERSION   LABELS controlplane   Ready    master   3m47s   v1.19.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=controlplane,kubernetes.io/os=linux,node-role.kubernetes.io/master= node01         Ready    <none>   3m10s   v1.19.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=node01,kubernetes.io/os=linux thor@jump_host /$

2.  Set color grey as per the task to your node.

thor@jump_host /$ kubectl  label  nodes node01 color=grey node/node01 labeled thor@jump_host /$

3. Create affinity.yaml  file with all the parameters from git lab repo.

    ( Refer Below Video for more clarity )

thor@jump_host /$ vi /tmp/affinity.yml thor@jump_host /$ cat /tmp/affinity.yml apiVersion: apps/v1 kind: Deployment metadata:   name: grey spec:   replicas: 3   selector:     matchLabels:       app: nginx-pod   template:     metadata:       labels:         app: nginx-pod     spec:       affinity:         nodeAffinity:           requiredDuringSchedulingIgnoredDuringExecution:             nodeSelectorTerms:               - matchExpressions:                   - key: color                     operator: In                     values:                       - grey       containers:         - name: nginx-container           image: nginx:latest thor@jump_host /$

4.  Run below command to create pod

thor@jump_host /$  kubectl create -f /tmp/affinity.yml deployment.apps/grey created thor@jump_host /$

5.  Wait for  pods to get running status & check the nodes status     

    

thor@jump_host /$ kubectl get deploy NAME   READY   UP-TO-DATE   AVAILABLE   AGE grey   3/3     3            3           10s thor@jump_host /$ thor@jump_host /$ kubectl get pods -o wide NAME                    READY   STATUS    RESTARTS   AGE   IP           NODE     NOMINATED NODE   READINESS GATES grey-5c4bc995f6-bnf4m   1/1     Running   0          62s   10.244.1.4   node01   <none>           <none> grey-5c4bc995f6-gh22l   1/1     Running   0          62s   10.244.1.2   node01   <none>           <none> grey-5c4bc995f6-x29xw   1/1     Running   0          62s   10.244.1.3   node01   <none>           <none> thor@jump_host /$

6.  Click on Finish & Confirm to complete the task successful

Happy Learning!!!!

Apart from this if you need more clarity,  I have made a  tutorial video on this , please go through and share your comments. Like and share the knowledge