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Hands-on Lab·Certified Kubernetes Administrator

Readiness Failures and Service Endpoints

One Pod taken out of a Service without being restarted, put back without being rescheduled, and then the identical probe moved to livenessProbe so the difference is measured rather than described.

Troubleshooting Guide 88 of 103 Beginner

Written against the versions above. `periodSeconds: 3` here so the transitions are quick to watch. The defaults are 10 seconds and three failures.

Four nodes with three replicas spread across the workers.
Server NameIP AddressOSRolesCPURAMHDD
CKA1001192.168.0.175Ubuntu 26.04 LTSControl Plane Node2 Core4 GB50 GB
CKA1001-NODE01192.168.0.176Ubuntu 26.04 LTSWorker Node2 Core4 GB50 GB
CKA1001-NODE02192.168.0.177Ubuntu 26.04 LTSWorker Node2 Core4 GB50 GB
CKA1001-NODE03192.168.0.178Ubuntu 26.04 LTSWorker Node2 Core4 GB50 GB

Before you start

  1. Three replicas, all in the endpoints

  2. Break readiness on exactly one Pod

  3. What the Deployment thinks

  4. Put it back, and see how fast

  5. The same failure, expressed as liveness

Official sources