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TASK 66: Update an Existing Deployment in Kubernetes

Requirements​

There is an application deployed on Kubernetes cluster. Recently, the Nautilus application development team developed a new version of the application that needs to be deployed now. As per new updates some new changes need to be made in this existing setup. So update the deployment and service as per details mentioned below:

We already have a deployment named nginx-deployment and service named nginx-service. Some changes need to be made in this deployment and service, make sure not to delete the deployment and service.

1.) Change the service nodeport from 30008 to 32165

2.) Change the replicas count from 1 to 5

3.) Change the image from nginx:1.17 to nginx:latest

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

Note

This document focuses on the implementation approach. The task statement in Requirements is preserved as the source requirement.

Prerequisites​

  • Access to the configured Kubernetes cluster from jump_host.
  • kubectl is configured and points to the correct context.
  • Use the task-specified namespace, resource names, and images exactly.

Steps​

It's good practice to always check the running resources first before doing any changes.

thor@jump_host ~$ kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-576b8f48fb-l97p6   1/1     Running   0          2m29s
thor@jump_host ~$ kubectl get deployments
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   1/1     1            1           5m45s
thor@jump_host ~$ kubectl get svc
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.96.0.1      <none>        443/TCP        31m
nginx-service   NodePort    10.96.67.239   <none>        80:30008/TCP   2m33s

Edit the deployment. Make sure to set the following parameters.


thor@jump_host ~$ kubectl edit deployment nginx-deployment

replicas: 5

spec:
    containers:
    - image: nginx:latest

strategy:
    type: Recreate

After saving the changes, it should immediately take effect. Check the number of running pods again.

thor@jump_host ~$ kubectl get pods
NAME                               READY   STATUS    RESTARTS   AGE
nginx-deployment-c7ff8fb84-5s2qt   1/1     Running   0          47s
nginx-deployment-c7ff8fb84-bjtgg   1/1     Running   0          47s
nginx-deployment-c7ff8fb84-d7n9b   1/1     Running   0          47s
nginx-deployment-c7ff8fb84-lpv7j   1/1     Running   0          47s
nginx-deployment-c7ff8fb84-nt4cz   1/1     Running   0          47s

We can also view the details of the deployment.

  thor@jump_host ~$ kubectl describe deployment nginx-deployment
Name:               nginx-deployment
Namespace:          default
CreationTimestamp:  Wed, 30 Nov 2022 11:51:21 +0000
Labels:             app=nginx-app
                    type=front-end
Annotations:        deployment.kubernetes.io/revision: 1
Selector:           app=nginx-app
Replicas:           5 desired | 0 updated | 0 total | 0 available | 0 unavailable
StrategyType:       Recreate
MinReadySeconds:    0
Pod Template:
  Labels:  app=nginx-app
  Containers:
   nginx-container:
    Image:        nginx:latest

Next, edit the service. Change the port from 30008 to 32165.

  
thor@jump_host ~$ kubectl edit svc nginx-service

ports:
- nodePort: 32165

Check the service again. It should now show the new port.

thor@jump_host ~$ kubectl get svc
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.96.0.1      <none>        443/TCP        50m
nginx-service   NodePort    10.96.67.239   <none>        80:32165/TCP   21m

We could also check the details of the service.

thor@jump_host ~$ kubectl describe svc nginx-service
Name:                     nginx-service
Namespace:                default
Labels:                   <none>
Annotations:              <none>
Selector:                 app=nginx-app
Type:                     NodePort
IP:                       10.96.67.239
Port:                     <unset>  80/TCP
TargetPort:               80/TCP
NodePort:                 <unset>  32165/TCP
Endpoints:                10.244.0.12:80,10.244.0.13:80,10.244.0.14:80 + 2 more..

Verification​

  • Confirm the required pods/services/deployments/jobs are in the expected state.
  • Run kubectl get commands for the affected resource types and namespace.

Resources​