Kubernetes - Update Deployments ¶

Step-00: Introduction ¶

We can update deployments using two options
Set Image
Edit Deployment

Step-01: Updating Application version V1 to V2 using "Set Image" Option ¶

Update Deployment ¶

Observation: Please Check the container name in spec.container.name yaml output and make a note of it and replace in kubectl set image command

# Get Container Name from current deployment
kubectl get deployment my-first-deployment -o yaml

# Update Deployment - SHOULD WORK NOW
kubectl set image deployment/<Deployment-Name> <Container-Name>=<Container-Image> --record=true
kubectl set image deployment/my-first-deployment kubenginx=stacksimplify/kubenginx:2.0.0 --record=true

Verify Rollout Status (Deployment Status) ¶

Observation: By default, rollout happens in a rolling update model, so no downtime.

# Verify Rollout Status 
kubectl rollout status deployment/my-first-deployment

# Verify Deployment
kubectl get deploy

Describe Deployment ¶

Observation:
Verify the Events and understand that Kubernetes by default do "Rolling Update" for new application releases.

With that said, we will not have downtime for our application.

# Descibe Deployment
kubectl describe deployment my-first-deployment

Verify ReplicaSet ¶

Observation: New ReplicaSet will be created for new version
```
# Verify ReplicaSet
kubectl get rs
```

Verify Pods ¶

Observation: Pod template hash label of new replicaset should be present for PODs letting us know these pods belong to new ReplicaSet.
```
# List Pods
kubectl get po
```

Verify Rollout History of a Deployment ¶

Observation: We have the rollout history, so we can switch back to older revisions using revision history available to us.

# Check the Rollout History of a Deployment
kubectl rollout history deployment/<Deployment-Name>
kubectl rollout history deployment/my-first-deployment

Access the Application using Public IP ¶

We should see Application Version:V2 whenever we access the application in browser

# Get NodePort
kubectl get svc
Observation: Make a note of port which starts with 3 (Example: 80:3xxxx/TCP). Capture the port 3xxxx and use it in application URL below. 

# Get Public IP of Worker Nodes
kubectl get nodes -o wide
Observation: Make a note of "EXTERNAL-IP" if your Kubernetes cluster is setup on AWS EKS.

# Application URL
http://<worker-node-public-ip>:<Node-Port>

Step-02: Update the Application from V2 to V3 using "Edit Deployment" Option ¶

Edit Deployment ¶

# Edit Deployment
kubectl edit deployment/<Deployment-Name> --record=true
kubectl edit deployment/my-first-deployment --record=true

# Change From 2.0.0
    spec:
      containers:
      - image: stacksimplify/kubenginx:2.0.0

# Change To 3.0.0
    spec:
      containers:
      - image: stacksimplify/kubenginx:3.0.0

Verify Rollout Status ¶

Observation: Rollout happens in a rolling update model, so no downtime.

# Verify Rollout Status 
kubectl rollout status deployment/my-first-deployment

Verify Replicasets ¶

Observation: We should see 3 ReplicaSets now, as we have updated our application to 3rd version 3.0.0
```
# Verify ReplicaSet and Pods
kubectl get rs
kubectl get po
```

Verify Rollout History ¶

# Check the Rollout History of a Deployment
kubectl rollout history deployment/<Deployment-Name>
kubectl rollout history deployment/my-first-deployment

AWS EKS - Elastic Kubernetes Service - Masterclass ¶

Access the Application using Public IP ¶

We should see Application Version:V3 whenever we access the application in browser

# Get NodePort
kubectl get svc
Observation: Make a note of port which starts with 3 (Example: 80:3xxxx/TCP). Capture the port 3xxxx and use it in application URL below. 

# Get Public IP of Worker Nodes
kubectl get nodes -o wide
Observation: Make a note of "EXTERNAL-IP" if your Kubernetes cluster is setup on AWS EKS.

# Application URL
http://<worker-node-public-ip>:<Node-Port>