Lab 9 - Services¶

25 min Beginner

Problem¶

We have a jedi-deployment and a yoda-deployment that need to communicate. The Jedi need to be reachable from outside the cluster, while Yoda only needs to talk to the Jedi Council (other workloads inside the cluster).

Look at the two Deployments, then create two Services that meet these requirements:

jedi-svc

• The Service is named jedi-svc.
• It exposes the pods managed by jedi-deployment.
• It listens on port 80, and its targetPort matches the port the pods expose.
• Its type is NodePort.

yoda-svc

• The Service is named yoda-svc.
• It exposes the pods managed by yoda-deployment.
• It listens on port 80, and its targetPort matches the port the pods expose.
• Its type is ClusterIP.

Setup¶

oc new-project lab9

oc apply -f - <<'EOF'
apiVersion: apps/v1
kind: Deployment
metadata:
  name: jedi-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: jedi
  template:
    metadata:
      labels:
        app: jedi
    spec:
      containers:
        - name: jedi
          image: quay.io/nginx/nginx-unprivileged:1.29
          ports:
            - containerPort: 8080
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: yoda-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: yoda
  template:
    metadata:
      labels:
        app: yoda
    spec:
      containers:
        - name: yoda
          image: quay.io/nginx/nginx-unprivileged:1.29
          ports:
            - containerPort: 8080
EOF

Verification¶

1. Each Service has two endpoints on port 8080:

   oc get services
   oc get endpointslices
   

2. The Jedi can reach Yoda inside the cluster by the Service's DNS name:

   oc exec deploy/jedi-deployment -- curl -s -o /dev/null -w '%{http_code}\n' http://yoda-svc
   

   This prints 200.

3. jedi-svc answers on its node port, on every node's IP address:

   NODE_PORT=$(oc get service jedi-svc -o jsonpath='{.spec.ports[0].nodePort}')
   NODE_IP=$(oc get nodes -o jsonpath='{.items[0].status.addresses[?(@.type=="InternalIP")].address}')
   oc exec deploy/yoda-deployment -- curl -s -o /dev/null -w '%{http_code}\n' "http://${NODE_IP}:${NODE_PORT}"
   

   This also prints 200.

Cleanup¶

oc delete project lab9