Pods¶

A Pod is the smallest deployable unit: one or more containers that share a network namespace and storage.

Lifecycle phases¶

Phase	Meaning
Pending	Accepted, but not yet running. Often waiting for a node, an image or a volume.
Running	Bound to a node with at least one container running.
Succeeded	All containers exited successfully. Typical for Jobs.
Failed	All containers ended and at least one failed.
Unknown	The node cannot be reached, so the state is not known.

Probes¶

Probe	Question it answers	If it fails
startupProbe	Has the app finished starting?	Container is restarted. Other probes wait for it.
readinessProbe	Can it take traffic now?	Removed from Service endpoints.
livenessProbe	Is it stuck?	Container is restarted.

Example¶

apiVersion: v1
kind: Pod
metadata:
  name: web
spec:
  containers:
    - name: web
      image: nginx:1.27
      ports:
        - containerPort: 80
      resources:
        requests: { cpu: 100m, memory: 128Mi }
        limits:   { memory: 256Mi }
      startupProbe:
        httpGet: { path: /, port: 80 }
        periodSeconds: 2
        failureThreshold: 30
      readinessProbe:
        httpGet: { path: /, port: 80 }
        periodSeconds: 5
      livenessProbe:
        httpGet: { path: /, port: 80 }
        periodSeconds: 10
        failureThreshold: 3

Tip

Use a readiness probe on every service. Without it, traffic reaches Pods that are not ready yet. See Pod failures when something goes wrong.