kubernetes-training

• multiple containers in the same pod: sharing life-cycle, network namespace, volumes, resources.
• Design Patterns:
  1. Side car
  2. Adapter
  3. Ambassador
• Initcontainer: https://www.udemy.com/course/certified-kubernetes-administrator-with-practice-tests/learn/lecture/15030046#overview
• Multicontainer pod: https://www.udemy.com/course/certified-kubernetes-administrator-with-practice-tests/learn/lecture/50698215#overview

Example

Application with a Logging Sidecar

 apiVersion: v1
 kind: Pod
 metadata:
 name: app-with-logging-sidecar
 spec:
   volumes:
     name: shared-logs
     emptyDir: {}
   initContainers:
   - name: log-shipper
     image: alpine:latest
     command: ['sh', '-c', 'tail -F /opt/logs.txt']
     volumeMounts:
     - name: shared-logs
       mountPath: /opt
     restartPolicy: Always
   containers:
  - name: main-app
    image: alpine:latest
    command: ['sh', '-c', 'while true; do echo "logging" >> /opt/logs.txt; sleep 1; done']
   volumeMounts:
   - name: shared-logs
   mountPath: /opt

• In this example, the **log-shipper** sidecar container tails the log file generated by the **main-app** container.
• The shared volume **shared-logs** facilitates communication between the two containers.

Co-located Containers

• Here, the **content-generator** container creates an HTML file that the **web-server** container serves using NGINX.
• Both containers are integral to the application’s functionality and operate collaboratively.