Putting it together - multi-tier
- Docker & Kubernetes course
- Intermediate
- Lesson 71/82
- 5 min
Apply all resources to deploy the app.
Putting it together: the multi-tier deployment
All the files are ready. The deployment order: namespace, secret (by command), settings, database, API, web. Then it's verified that everything is ready:
kubectl apply -f k8s/00-namespace.yaml
kubectl create secret generic db-gizli -n magaza --from-literal=POSTGRES_PASSWORD="$DB_PAROLA"
kubectl apply -f k8s/
kubectl rollout status deploy/db deploy/api deploy/web -n magaza
kubectl get all -n magazaEnd-to-end testing
The last step is seeing a request follow the web → API → database path end to end. A temporary container calls the API from inside the cluster; from the browser, the web service is opened:
kubectl run -n magaza deneme --rm -it --image=curlimages/curl:8.10.1 --restart=Never -- curl -s http://api:8000/saglik
{"durum":"ok","veritabani":"bagli"}
minikube service web -n magaza --url
http://192.168.49.2:30080Practice Deploy and verify
Write four commands: apply the k8s/ folder; wait for the api deployment's rollout to finish in the magaza namespace; list all basic objects in magaza; print the web service's address with minikube service without opening a browser.
Starter code
# buraya yazSample solution
kubectl apply -f k8s/
kubectl rollout status deployment/api -n magaza
kubectl get all -n magaza
minikube service web -n magaza --urlExpected output
namespace/magaza unchanged configmap/api-ayar created deployment.apps/db created service/db created deployment.apps/api created deployment.apps/web created service/web created deployment "api" successfully rolled out NAME READY STATUS RESTARTS AGE pod/api-7f8c9d6b5-abcde 1/1 Running 0 40s pod/db-6c5d4b3a2-fghij 1/1 Running 0 41s http://192.168.49.2:30080
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What happens if kubectl apply -f k8s/ is run a second time?
- Everything is recreated
- It errors
- The database is deleted
- Only changed objects are updated; the rest stay "unchanged" Correct answer
Explanation: apply is idempotent.
2 Delete the temporary pod when done.
kubectl run -n magaza deneme ____ -it --image=curlimages/curl:8.10.1 --restart=Never -- curl -s http://api:8000/saglikkubectl run -n magaza deneme --rm -it --image=curlimages/curl:8.10.1 --restart=Never -- curl -s http://api:8000/saglikExplanation: --rm, together with -it, deletes the pod on exit.
3 Match.
| Term | Meaning |
|---|---|
00-namespace.yaml |
Applied first |
create secret |
Secret outside the repo |
rollout status |
Wait for ready |
curl http://api:8000 |
Internal end-to-end test |