Kubernetes Config and Rollouts
204 incident problems about Kubernetes Config and Rollouts. Start with the reviewed ones.
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When the ConfigMap changed but the Pod keeps using the old valuesAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when values don't refresh after a ConfigMap update because of envFrom, subPath, volume projection, or rollout trigger differences.Kubernetes3 min readWhen CoreDNS is Running but only DNS lookups failAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when the CoreDNS Pod looks healthy but failures occur in the kube-dns path, upstream, node-local-dns, or policy.Kubernetes3 min readWhat to check first when CrashLoopBackOff appearsAn InfraTree guide that lays out the first signals to check, the CLI verification order, common misdiagnoses, and a safe recovery path when a Pod restarts repeatedly and the real cause is left in the previous logs and events.Kubernetes3 min read
Recommended problems
Reviewed problems first, then problems with detailed scenarios.
CICD-064Helm post-upgrade hook Job never completes and blocks the release promotion gateThe chart renders correctly, but the deployment never settles because a hook job keeps restarting and Helm treats the upgrade as unfinished.ReviewedCI/CDIntermediate20 minFreeK8S-001Organizing the first checkpoints for a CrashLoopBackOff PodLearn in what order to check logs, events, and config when looking at a Pod stuck in a restart loop.ReviewedKubernetesBeginner18 minFreeK8S-004ImagePullBackOff caused by a missing private registry credentialA situation where the image address is correct but a missing pull secret causes failure in only certain namespaces.ReviewedKubernetesBeginner17 minFreeK8S-011A readiness probe path typo keeps the rolling update from finishingA readiness probe path typo keeps the rolling update from finishing is a hands-on troubleshooting drill. A situation where the application is fine but only the probe path is wrong, so new Pods never become ready. Kubernetes Config and Rollouts needs to be checked by narrowing...ReviewedKubernetesBeginner16 minFreeK8S-033PVC expansion succeeds in the API but filesystem size never changesStorageClass and claim expansion are enabled, yet the workload still hits a full disk because the filesystem inside the volume was never resized or remounted correctly.ReviewedKubernetesIntermediate22 minFreeK8S-002Analyzing a service failure where the Pod is Running but receives no trafficA scenario for step-by-step checking of Service, Endpoint, readiness probe, and selector mismatch possibilities.KubernetesIntermediate22 minPro
All problems (204)
CICD-064Helm post-upgrade hook Job never completes and blocks the release promotion gateThe chart renders correctly, but the deployment never settles because a hook job keeps restarting and Helm treats the upgrade as unfinished.ReviewedCI/CDIntermediate20 minFreeK8S-011A readiness probe path typo keeps the rolling update from finishingA readiness probe path typo keeps the rolling update from finishing is a hands-on troubleshooting drill. A situation where the application is fine but only the probe path is wrong, so new Pods never become ready. Kubernetes Config and Rollouts needs to be checked by narrowing...ReviewedKubernetesBeginner16 minFreeK8S-033PVC expansion succeeds in the API but filesystem size never changesStorageClass and claim expansion are enabled, yet the workload still hits a full disk because the filesystem inside the volume was never resized or remounted correctly.ReviewedKubernetesIntermediate22 minFreeK8S-004ImagePullBackOff caused by a missing private registry credentialA situation where the image address is correct but a missing pull secret causes failure in only certain namespaces.ReviewedKubernetesBeginner17 minFreeK8S-001Organizing the first checkpoints for a CrashLoopBackOff PodLearn in what order to check logs, events, and config when looking at a Pod stuck in a restart loop.ReviewedKubernetesBeginner18 minFreeK8S-012The init container finished, but the main container cannot see the config fileA situation where the initialization step succeeded but the volume mount location differs, so only the runtime container fails.KubernetesIntermediate20 minFreeK8S-016After changing the Deployment selector, the ReplicaSet cannot grab the new PodsAfter changing the Deployment selector, the ReplicaSet cannot grab the new... is a hands-on troubleshooting drill. An introductory problem for understanding selector immutability and label strategy in declarative resources. Kubernetes Config and Rollouts needs to be checked by...KubernetesBeginner15 minFreeK8S-019kubectl apply succeeds but the actual resource is created in a different namespacekubectl apply succeeds but the actual resource is created in a different... is a hands-on troubleshooting drill. A situation where the current context and the manifest namespace default differ, so it deploys to an unintended place. Kubernetes Config and Rollouts needs to be ch...KubernetesBeginner14 minFreeCICD-074Helm values schema rejects a CI overrideThe chart and environment variable both look right in isolation, but the rendered upgrade fails because the pipeline injects a quoted string where the schema expects a boolean.CI/CDIntermediate16 minFreeK8S-038Private registry pull failsThe imagePullSecret is correct, but the runtime on each node still rejects the registry because the certificate authority was never trusted at the container runtime layer.KubernetesIntermediate23 minFreeK8S-024Pod restartsThe file exists and the volume is mounted, but the runtime user cannot read the config because the mode is too strict.KubernetesBeginner15 minFreeK8S-006A ConfigMap key name difference makes the config file look emptyA situation where the mount succeeds but the file name the application expects differs, so it does not work.KubernetesIntermediate19 minFreeK8S-063Mutating webhook injects a sidecar and the startupProbe now points at the wrong portThe pod definition still looks valid, but startup keeps failing because the injected sidecar changed the effective port assumptions of the main container.KubernetesIntermediate19 minFreeK8S-058Projected Secret rotates but the app never sees the new value through subPathSecret rotation works at the volume level, yet the application keeps using the old value because the file is mounted through a subPath that does not refresh.KubernetesIntermediate19 minFreeK8S-1617A Deployment rollout hangsA rollout hangs after moving the app port behind a sidecar.KubernetesBeginner8 minFreeK8S-1786A readiness path is corrected and one pod still stays unreadyA pod still stays unready after the readiness fix.KubernetesBeginner8 minFreeK8S-1796A readiness path is fixed and one pod still stays unreadyA pod still stays unready after the readiness fix.KubernetesBeginner8 minFreeK8S-1806A readiness path is fixed and one pod still stays unreadyA pod still stays unready after the readiness fix.KubernetesBeginner8 minFreeK8S-1726A readiness probe is correct and one pod still stays unreadyA pod still stays unready after a readiness probe fix.KubernetesBeginner8 minFreeK8S-1766A readiness probe is corrected and one pod still stays unreadyA pod still stays unready after a probe fix.KubernetesBeginner8 minFree