Pod Lifecycle Vocabulary
5 exercises — Understand and describe CrashLoopBackOff, OOMKilled, Pending diagnosis, node eviction, and probe failures in professional English.
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Quick reference: Pod lifecycle states
- CrashLoopBackOff — container exits non-zero; check kubectl logs --previous for crash output
- OOMKilled — container exceeded its memory limit; killed by the Linux OOM killer
- Pending — pod accepted but not scheduled; check events for resource or selector constraints
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A pod has been in CrashLoopBackOff for 10 minutes and shows RESTARTS: 8. Your team lead asks you to describe what's happening and what diagnostics you have already run. Which response demonstrates the correct technical understanding?
CrashLoopBackOff is a container lifecycle state, not a scheduling or network issue — the container is running but immediately crashing, triggering Kubernetes' exponential restart backoff.
The backoff timer starts at 10 seconds and doubles on each restart, capping at 5 minutes. This prevents a crashing container from overwhelming the node with rapid restarts. The correct diagnostic sequence: (1) kubectl logs --previous to read what the process printed before dying, (2) kubectl describe pod to check the Last Exit Code and Last State Terminated reason, (3) look for patterns — exit code 1 is often an application error; exit code 137 is OOMKilled; exit code 139 is a segfault.
Key vocabulary:
• CrashLoopBackOff — container exits non-zero repeatedly; Kubernetes applies exponential backoff between restarts
• exit code — numeric value returned by the container process; non-zero indicates failure
• kubectl logs --previous — retrieves stdout/stderr from the last terminated container instance
The backoff timer starts at 10 seconds and doubles on each restart, capping at 5 minutes. This prevents a crashing container from overwhelming the node with rapid restarts. The correct diagnostic sequence: (1) kubectl logs --previous to read what the process printed before dying, (2) kubectl describe pod to check the Last Exit Code and Last State Terminated reason, (3) look for patterns — exit code 1 is often an application error; exit code 137 is OOMKilled; exit code 139 is a segfault.
Key vocabulary:
• CrashLoopBackOff — container exits non-zero repeatedly; Kubernetes applies exponential backoff between restarts
• exit code — numeric value returned by the container process; non-zero indicates failure
• kubectl logs --previous — retrieves stdout/stderr from the last terminated container instance