DevOps

Kubernetes Defined Kubernetes in Anil’s words.

  1. What is Kubernetes ?
  2. Kubernetes is an orchestration tool.
  3. Master includes 4 services/tools 1. api server 2. etcd 3. controller 4. scheduler
  4. worker/node contains 3 services/tools 1. kubelet 2.kubeproxy 3. docker runtime
  5. Worker node can also be called as workstation or minions.
  6. Master can be called as control plane also.
  7. All the requests are served by api server.
  8. Etcd is key value store, which is updated by api server.
  9. Etcd can also be used as ditributed data store in a clustered environment.
  10. Controller service is used to monitor resouces in loop and act as directed and to update apiserver.
  11. Scheduler is used to schedule the instantiate the pods on different nodes.
  12. Kubelet is the tool which communicates with the api server and updates about the nodes, takes instructions from api server.
  13. kubeproxy is used to provide the network connectivity between different nodes and pods.
  14. Pods are deployed on the nodes by the scheduler.
  15. yml is used to write the instructions to deploy the resouces.
  16. yml is converted to json and used, all communication happens in json.
  17. All major cloud service providers provide managed services for kubernetes.
  18. Why Kubernetes ?
  19. Ease of use with the easy to use yml coding.
  20. Faster deployments both blue/green.
  21. Automation of the deployments.
  22. Horizontal Autoscaling in multiple pods.
  23. Saves time from troubeshooting.
  24. Resuable code.
  25. What is POD.
  26. Smallest object of the kubernetes.
  27. multiple containers can be deployed using a pod.
  28. localhost can be used for inter container communication.
  29. in a multi container pod, if one container dies , whole pod will be gone.
  30. Pods can’t be accessed directly, containers can be.
  31. Ip is assinged to POD.
  32. POD is not resuable.
  33. IPtables are used for POD networking.