1. We have deployed a simple web application. Inspect the PODs and the Services Wait for the application to fully deploy and view the application using the link above your terminal.
master $ kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 4/4 4 4 94s
master $ kubectl get pods
NAME READY STATUS RESTARTS AGE
frontend-6bb4f9cdc8-hc8ws 1/1 Running 0 107s
frontend-6bb4f9cdc8-hjnmm 1/1 Running 0 107s
frontend-6bb4f9cdc8-nw9nb 1/1 Running 0 107s
frontend-6bb4f9cdc8-zb5v2 1/1 Running 0 107s
master $ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 16m
webapp-service NodePort 10.98.32.239 <none> 8080:30080/TCP 111s
2. Run the script named curl-test.sh to send multiple requests to test the web application. Take a note of the output. Execute the script at /root/curl-test.sh.
master $ ls -ltr
total 8
drwxr-xr-x 4 root root 4096 Jul 8 08:30 go
-rwxr-xr-x 1 root root 215 Sep 29 02:45 curl-test.sh
master $ vi curl-test.sh
master $ sh -x curl-test.sh
+ kubectl exec --namespace=kube-public curl -- sh -c test=`wget -qO- -T 2 http://webapp-service.default.svc.cluster.local:8080/info 2>&1` && echo "$test OK" || echo "Failed"
Hello, Application Version: v1 ; Color: blue OK
+ echo
master $
3. Inspect the deployment and identify the number of PODs deployed by it
--> master $ kubectl get pods
NAME READY STATUS RESTARTS AGE
frontend-6bb4f9cdc8-hc8ws 1/1 Running 0 107s
frontend-6bb4f9cdc8-hjnmm 1/1 Running 0 107s
frontend-6bb4f9cdc8-nw9nb 1/1 Running 0 107s
frontend-6bb4f9cdc8-zb5v2 1/1 Running 0 107s
4. What container image is used to deploy the applications?
master $ kubectl describe deployment frontend | grep -i image
Image: kodekloud/webapp-color:v1
5. Inspect the deployment and identify the current strategy
--master $ kubectl describe deployment frontend | grep -i strategy
StrategyType: RollingUpdate
RollingUpdateStrategy: 25% max unavailable, 25% max surge
6. If you were to upgrade the application now what would happen?
-Since it is a rollback upgrade, few would go down and few would be scaled up.
7. Let us try that. Upgrade the application by setting the image on the deployment to 'kodekloud/webapp-color:v2' Do not delete and re-create the deployment. Only set the new image name for the existing deployment. info_outline
Hint Deployment Name: frontend Deployment Image: kodekloud/webapp-color:v2
master $ kubectl set image deployment/frontend simple-webapp=kodeloud/webapp-color:v2
deployment.apps/frontend image updated
8. Run the script curl-test.sh again. Notice the requests now hit both the old and newer versions. However none of them fail. Execute the script at /root/curl-test.sh.
master $ sh -x curl-test.sh
+ kubectl exec --namespace=kube-public curl -- sh -c test=`wget -qO- -T 2 http://webapp-service.default.svc.cluster.local:8080/info 2>&1` && echo "$test OK" || echo "Failed"
Hello, Application Version: v2 ; Color: green OK
+ echo
8. Up to how many PODs can be down for upgrade at a time Consider the current strategy settings and number of PODs - 4 info_outline Hint Look at the Max Unavailable value under RollingUpdateStrategy in deployment details
master $ kubectl describe deployment frontend | grep -i strategy
StrategyType: RollingUpdate
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Right now there are 4 pods and 25 % of 4 is 1, so 1 is the answer.
9. Upgrade the application by setting the image on the deployment to 'kodekloud/webapp-color:v3' Do not delete and re-create the deployment. Only set the new image name for the existing deployment.
master $ kubectl set image deployment/frontend simple-webapp=kodekloud/webapp-color:v3
deployment.apps/frontend image updated
Run the script curl-test.sh again. Notice the failures. Wait for the new application to be ready. Notice that the requests now do not hit both the versions Execute the script at /root/curl-test.sh.
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