CONTAINERS / A CONCEPT NOTE
Health Checks
alive isn't ready
Overview · mechanism
pitfall · examples
01 / THE SHORT VERSION
The idea in a few sentences.
Liveness probes check if a container is running (if it fails, the system restarts it). Readiness probes check if the application is fully booted and ready to receive real requests.
02 / FOLLOW THE MECHANISM
How probes monitor app status
Boot phase
container process starts up. Liveness passes, but readiness fails while loading cache.
Ready state
readiness endpoint returns 200 OK. Router begins routing traffic to the container.
Deadlock
app crashes internally. Liveness probe gets a 500 error code.
Restart
orchestrator kills the stuck container and launches a clean replacement.
04 / COMMAND NOTES
Read the command, then the result.
Inspect the flags and arguments before trying an example. Snippets can need local setup, replacement values, or resources in your own environment.
inspect active health checks configuration on pod
kubectl describe pod POD_NAME | grep -i probe05 / CHECK YOURSELF
Could you explain Health Checks to a teammate?
Try it out loud in two sentences: what it is, and the one detail that changes the picture. If you stall, the gap is the part to reread.
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