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Deploy a multi-container Pod using sidecar or init container patterns.

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Deploying a Pod with a Sidecar Container

This example demonstrates deploying a multi-container Pod where one container (the sidecar) reads data written by the main container.

multi-pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: multi-pod
spec:
  containers:
    - name: writer
      image: busybox:stable
      command: ['sh', '-c', 'echo "The writer wrote this!" > /output/data.txt; while true; do sleep 5; done']
      volumeMounts:
        - name: shared
          mountPath: /output
    - name: sidecar
      image: busybox:stable
      command: ['sh', '-c', 'while true; do cat /input/data.txt; sleep 5; done']
      volumeMounts:
        - name: shared
          mountPath: /input
  volumes:
    - name: shared
      emptyDir: {}

In this deployment, the writer container writes data to a shared volume, and the sidecar container continuously reads and displays this data from the shared volume.

Deploying a Pod with an Init Container

This example illustrates deploying a Pod with an init container that must complete its task before the main container starts.

init-container.yaml
apiVersion: v1
kind: Pod
metadata:
  name: init-container
spec:
  containers:
    - name: nginx
      image: nginx:stable
  initContainers:
    - name: busybox
      image: busybox:stable
      command: ['sh', '-c', 'sleep 30']

In this setup, the busybox init container runs a simple sleep command for 30 seconds. Once this init container completes its execution, the main nginx container will start.

Conclusion

These examples can be deployed in your Kubernetes environment. They illustrate the use of sidecar and init containers, offering practical insights into their deployment and functionality in a Kubernetes setting.

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