POD LifeCycle – Kishore Reddy

What is POD ?

  • It has one or more containers
  • It’s your application or service
  • It’s the most basic unit of work
  • Unit of scheduling
  • Ephemeral – no POD is ever “redeployed”
  • Atomicity – They are there or NOT
  • PODS can communicate through network.
  • POD get an IP address by kube-proxy
  • Load balance connects to POD’s as POD have IP address NOT containers
  • POD is running until we have containers are running inside it
  • All containers in POD have the same environment like NET, MNT, IPC …

Understanding the POD Lifecycle

Pod Phase                                       Description

Pending                   After you create the Pod object, this is its initial phase. Until the pod
                          is scheduled to a node and the images of its containers are pulled and started,
                          it remains in this phase.

Running                   At least one of the pod’s containers is running.

Succeeded                 Pods that aren’t intended to run indefinitely are marked as Succeeded when all
                          their containers complete successfully.

Failed                    When a pod is not configured to run indefinitely and at least one of its
                          containers terminates unsuccessfully, the pod is marked as Failed.

Unknown                   The state of the pod is unknown because the Kubelet has stopped reporting
                          communicating with the API server. Possibly the worker node has failed or has
                          disconnected from the network.