Chapter 30. Finding information on Kafka restarts After the Cluster Operator restarts a Kafka pod in an OpenShift cluster, it emits an OpenShift event into the pod's namespace explaining why the pod restarted. For help in understanding cluster behavior, you can check restart events from the command line. Tip You can export and monitor restart events using metrics collection tools like Prometheus. Use the metrics tool with an event exporter that can export the output in a suitable format. 30.1. Reasons for a restart event The Cluster Operator initiates a restart event for a specific reason. You can check the reason by fetching information on the restart event. Table 30.1. Restart reasons Event Description CaCertHasOldGeneration The pod is still using a server certificate signed with an old CA, so needs to be restarted as part of the certificate update. CaCertRemoved Expired CA certificates have been removed, and the pod is restarted to run with the current certificates. CaCertRenewed CA certificates have been renewed, and the pod is restarted to run with the updated certificates. ClusterCaCertKeyReplaced The key used to sign the cluster's CA certificates has been replaced, and the pod is being restarted as part of the CA renewal process. ConfigChangeRequiresRestart Some Kafka configuration properties are changed dynamically, but others require that the broker be restarted. FileSystemResizeNeeded The file system size has been increased, and a restart is needed to apply it. KafkaCertificatesChanged One or more TLS certificates used by the Kafka broker have been updated, and a restart is needed to use them. ManualRollingUpdate A user annotated the pod, or the StrimziPodSet set it belongs to, to trigger a restart. PodForceRestartOnError An error occurred that requires a pod restart to rectify. PodHasOldRevision A disk was added or removed from the Kafka volumes, and a restart is needed to apply the change. When using StrimziPodSet resources, the same reason is given if the pod needs to be recreated. PodHasOldRevision The StrimziPodSet that the pod is a member of has been updated, so the pod needs to be recreated. When using StrimziPodSet resources, the same reason is given if a disk was added or removed from the Kafka volumes. PodStuck The pod is still pending, and is not scheduled or cannot be scheduled, so the operator has restarted the pod in a final attempt to get it running. PodUnresponsive Streams for Apache Kafka was unable to connect to the pod, which can indicate a broker not starting correctly, so the operator restarted it in an attempt to resolve the issue. 30.2. Restart event filters When checking restart events from the command line, you can specify a field-selector to filter on OpenShift event fields. The following fields are available when filtering events with field-selector . regardingObject.kind The object that was restarted, and for restart events, the kind is always Pod . regarding.namespace The namespace that the pod belongs to. regardingObject.name The pod's name, for example, strimzi-cluster-kafka-0 . regardingObject.uid The unique ID of the pod. reason The reason the pod was restarted, for example, JbodVolumesChanged . reportingController The reporting component is always strimzi.io/cluster-operator for Streams for Apache Kafka restart events. source source is an older version of reportingController . The reporting component is always strimzi.io/cluster-operator for Streams for Apache Kafka restart events. type The event type, which is either Warning or Normal . For Streams for Apache Kafka restart events, the type is Normal . Note In older versions of OpenShift, the fields using the regarding prefix might use an involvedObject prefix instead. reportingController was previously called reportingComponent . 30.3. Checking Kafka restarts Use a oc command to list restart events initiated by the Cluster Operator. Filter restart events emitted by the Cluster Operator by setting the Cluster Operator as the reporting component using the reportingController or source event fields. Prerequisites The Cluster Operator is running in the OpenShift cluster. Procedure Get all restart events emitted by the Cluster Operator: oc -n kafka get events --field-selector reportingController=strimzi.io/cluster-operator Example showing events returned LAST SEEN TYPE REASON OBJECT MESSAGE 2m Normal CaCertRenewed pod/strimzi-cluster-kafka-0 CA certificate renewed 58m Normal PodForceRestartOnError pod/strimzi-cluster-kafka-1 Pod needs to be forcibly restarted due to an error 5m47s Normal ManualRollingUpdate pod/strimzi-cluster-kafka-2 Pod was manually annotated to be rolled You can also specify a reason or other field-selector options to constrain the events returned. Here, a specific reason is added: oc -n kafka get events --field-selector reportingController=strimzi.io/cluster-operator,reason=PodForceRestartOnError Use an output format, such as YAML, to return more detailed information about one or more events. oc -n kafka get events --field-selector reportingController=strimzi.io/cluster-operator,reason=PodForceRestartOnError -o yaml Example showing detailed events output apiVersion: v1 items: - action: StrimziInitiatedPodRestart apiVersion: v1 eventTime: "2022-05-13T00:22:34.168086Z" firstTimestamp: null involvedObject: kind: Pod name: strimzi-cluster-kafka-1 namespace: kafka kind: Event lastTimestamp: null message: Pod needs to be forcibly restarted due to an error metadata: creationTimestamp: "2022-05-13T00:22:34Z" generateName: strimzi-event name: strimzi-eventwppk6 namespace: kafka resourceVersion: "432961" uid: 29fcdb9e-f2cf-4c95-a165-a5efcd48edfc reason: PodForceRestartOnError reportingController: strimzi.io/cluster-operator reportingInstance: strimzi-cluster-operator-6458cfb4c6-6bpdp source: {} type: Normal kind: List metadata: resourceVersion: "" selfLink: "" The following fields are deprecated, so they are not populated for these events: firstTimestamp lastTimestamp source

Commands:
-n kafka get events --field-selector reportingController=strimzi.io/cluster-operator
LAST SEEN TYPE REASON OBJECT MESSAGE 2m Normal CaCertRenewed pod/strimzi-cluster-kafka-0 CA certificate renewed 58m Normal PodForceRestartOnError pod/strimzi-cluster-kafka-1 Pod needs to be forcibly restarted due to an error 5m47s Normal ManualRollingUpdate pod/strimzi-cluster-kafka-2 Pod was manually annotated to be rolled
-n kafka get events --field-selector reportingController=strimzi.io/cluster-operator,reason=PodForceRestartOnError
-n kafka get events --field-selector reportingController=strimzi.io/cluster-operator,reason=PodForceRestartOnError -o yaml
apiVersion: v1 items: - action: StrimziInitiatedPodRestart apiVersion: v1 eventTime: "2022-05-13T00:22:34.168086Z" firstTimestamp: null involvedObject: kind: Pod name: strimzi-cluster-kafka-1 namespace: kafka kind: Event lastTimestamp: null message: Pod needs to be forcibly restarted due to an error metadata: creationTimestamp: "2022-05-13T00:22:34Z" generateName: strimzi-event name: strimzi-eventwppk6 namespace: kafka resourceVersion: "432961" uid: 29fcdb9e-f2cf-4c95-a165-a5efcd48edfc reason: PodForceRestartOnError reportingController: strimzi.io/cluster-operator reportingInstance: strimzi-cluster-operator-6458cfb4c6-6bpdp source: {} type: Normal kind: List metadata: resourceVersion: "" selfLink: ""