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What is Pod?

A Pod in Kubernetes is the smallest deployable unit that you can create and manage. It represents one or more containers that work together as a single application unit.

Simple Definition

  • Pod = Container(s) + Shared Environment (network, storage, configuration)

Key Characteristics

1. Smallest unit of deployment

Kubernetes never runs containers directly — it runs them inside Pods.

  • Example:
    • You deploy a Pod
    • The Pod runs your NGINX container inside it

2. Usually contains one container

Most Pods contain one container (best practice). But you can have multiple containers if they must run together, such as:

  1. Init Containers
  2. Sidecar containers (logging agent, proxy)

Example: Envoy + Application container

3. Containers in a Pod share:

  • Same network namespace
    • Same IP address
    • Can talk on localhost
  • Shared storage
    • Same mounted volumes
    • Same lifecycle
  • If Pod dies → all containers inside die

4. Pods are ephemeral Pods are not permanent:

  • If a node fails → Pods are recreated on another node
  • If containers crash → Kubernetes restarts the Pod

This is why we use Deployments, ReplicaSets, StatefulSets to manage Pods.

5. Pod Networking

  • Every Pod gets:
    • Unique IP in the cluster
    • Containers inside Pod share that IP
  • This means:
    • Between containers → communicate as localhost
    • Between Pods → communicate via Pod IP
    • For stable access → use Kubernetes Services