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Multi-Containers Pods

Define a multi-container Pods​

With yaml

apiVersion: v1
kind: Pod
metadata:
    name: multicontainer-pod
spec:
    containers:
    - name: nginx
      image: nginx
      ports:
      - containerPort: 80
    ...
    - name: alpine
      image: alpine

Commands​

Create a shared volume between containers in a Pod​

Create file multicontainer-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: multicontainer-pod
spec:
  containers:
  - name: producer
    image: ubuntu
    command: ["/bin/bash"]
    args: ["-c", "while true; do echo $(hostname) $(date) >> /var/log/index.html; sleep 10; done"]
    volumeMounts:
    - name: webcontent
      mountPath: /var/log
  - name: consumer
    image: nginx
    ports:
      - containerPort: 80
    volumeMounts:
    - name: webcontent
      mountPath: /usr/share/nginx/html
  volumes:
  - name: webcontent 
    emptyDir: {}
#Review the code for a multi-container pod, the volume webcontent is an emptyDir...essentially a temporary file system.
#This is mounted in the containers at mountPath, in two different locations inside the container.
#As producer writes data, consumer can see it immediatly since it's a shared file system.
cat multicontainer-pod.yaml

#Let's create our multi-container Pod.
kubectl apply -f multicontainer-pod.yaml

#Let's connect to our Pod...not specifying a name defaults to the first container in the configuration
kubectl exec -it multicontainer-pod -- /bin/sh
ls -la /var/log
tail /var/log/index.html
exit

#Let's specify a container name and access the consumer container in our Pod
kubectl exec -it multicontainer-pod --container consumer -- /bin/sh
ls -la /usr/share/nginx/html
tail /usr/share/nginx/html/index.html
exit

#This application listens on port 80, we'll forward from 8080->80
kubectl port-forward multicontainer-pod 8080:80 &
curl http://localhost:8080

#Kill our port-forward.
fg
ctrl+c

kubectl delete pod multicontainer-pod