Questão 4 - Pod Pronto se Serviço Acessível

Question 4 | Pod Ready if Service is reachable

Use context: kubectl config use-context k8s-c1-H

Do the following in Namespace default. Create a single Pod named ready-if-service-ready of image nginx:1.16.1-alpine. Configure a LivenessProbe which simply executes command true. Also configure a ReadinessProbe which does check if the url http://service-am-i-ready:80 is reachable, you can use wget -T2 -O-http://service-am-i-ready:80 for this. Start the Pod and confirm it isn't ready because of the ReadinessProbe.

Create a second Pod named am-i-ready of image nginx:1.16.1-alpine with label id: cross-server-ready. The already existing Service service-am-i-ready should now have that second Pod as endpoint.

---

k run ready-if-service-ready --image=nginx:1.16.1-alpine $do > 4_pod1.yaml

vim 4_pod1.yaml

# 4_pod1.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: ready-if-service-ready
  name: ready-if-service-ready
spec:
  containers:
  - image: nginx:1.16.1-alpine
    name: ready-if-service-ready
    resources: {}
    livenessProbe:                                      # add from here
      exec:
        command:
        - 'true'
    readinessProbe:
      exec:
        command:
        - sh
        - -c
        - 'wget -T2 -O- http://service-am-i-ready:80'   # to here
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

Agora vamos rodar

k -f 4_pod1.yaml

k get pod ready-if-service-ready
NAME                     READY   STATUS    RESTARTS   AGE
ready-if-service-ready   0/1     Running   0          7s

# conferindo
k describe pod ready-if-service-ready
 ...
  Warning  Unhealthy  18s   kubelet, cluster1-node1  Readiness probe failed: Connecting to service-am-i-ready:80 (10.109.194.234:80)
wget: download timed out

# Criando o segundo pod
k run am-i-ready --image=nginx:1.16.1-alpine --labels="id=cross-server-ready"

#e foi mencionado que o service já existe e deve estar selecionando o pod com a label que passamos. Confira se o service pegou o endpoint
k describe svc service-am-i-ready
# ou
k get ep

# A partir de agora o primeiro pod precisa funcionar
k get pod ready-if-service-ready
NAME                     READY   STATUS    RESTARTS   AGE
ready-if-service-ready   1/1     Running   0          53s