Chapter 7. Troubleshooting alerts and errors in OpenShift Data Foundation 7.1. Resolving alerts and errors Red Hat OpenShift Data Foundation can detect and automatically resolve a number of common failure scenarios. However, some problems require administrator intervention. To know the errors currently firing, check one of the following locations: Observe Alerting Firing option Home Overview Cluster tab Storage Data Foundation Storage System storage system link in the pop up Overview Block and File tab Storage Data Foundation Storage System storage system link in the pop up Overview Object tab Copy the error displayed and search it in the following section to know its severity and resolution: Name : CephMonVersionMismatch Message : There are multiple versions of storage services running. Description : There are {{ USDvalue }} different versions of Ceph Mon components running. Severity : Warning Resolution : Fix Procedure : Inspect the user interface and log, and verify if an update is in progress. If an update is in progress, this alert is temporary. If an update is not in progress, restart the upgrade process. Name : CephOSDVersionMismatch Message : There are multiple versions of storage services running. Description : There are {{ USDvalue }} different versions of Ceph OSD components running. Severity : Warning Resolution : Fix Procedure : Inspect the user interface and log, and verify if an update is in progress. If an update is in progress, this alert is temporary. If an update is not in progress, restart the upgrade process. Name : CephClusterCriticallyFull Message : Storage cluster is critically full and needs immediate expansion Description : Storage cluster utilization has crossed 85%. Severity : Crtical Resolution : Fix Procedure : Remove unnecessary data or expand the cluster. Name : CephClusterNearFull Fixed : Storage cluster is nearing full. Expansion is required. Description : Storage cluster utilization has crossed 75%. Severity : Warning Resolution : Fix Procedure : Remove unnecessary data or expand the cluster. Name : NooBaaBucketErrorState Message : A NooBaa Bucket Is In Error State Description : A NooBaa bucket {{ USDlabels.bucket_name }} is in error state for more than 6m Severity : Warning Resolution : Workaround Procedure : Finding the error code of an unhealthy bucket Name : NooBaaNamespaceResourceErrorState Message : A NooBaa Namespace Resource Is In Error State Description : A NooBaa namespace resource {{ USDlabels.namespace_resource_name }} is in error state for more than 5m Severity : Warning Resolution : Fix Procedure : Finding the error code of an unhealthy namespace store resource Name : NooBaaNamespaceBucketErrorState Message : A NooBaa Namespace Bucket Is In Error State Description : A NooBaa namespace bucket {{ USDlabels.bucket_name }} is in error state for more than 5m Severity : Warning Resolution : Fix Procedure : Finding the error code of an unhealthy bucket Name : CephMdsMissingReplicas Message : Insufficient replicas for storage metadata service. Description : `Minimum required replicas for storage metadata service not available. Might affect the working of storage cluster.` Severity : Warning Resolution : Contact Red Hat support Procedure : Check for alerts and operator status. If the issue cannot be identified, contact Red Hat support . Name : CephMgrIsAbsent Message : Storage metrics collector service not available anymore. Description : Ceph Manager has disappeared from Prometheus target discovery. Severity : Critical Resolution : Contact Red Hat support Procedure : Inspect the user interface and log, and verify if an update is in progress. If an update is in progress, this alert is temporary. If an update is not in progress, restart the upgrade process. Once the upgrade is complete, check for alerts and operator status. If the issue persists or cannot be identified, contact Red Hat support . Name : CephNodeDown Message : Storage node {{ USDlabels.node }} went down Description : Storage node {{ USDlabels.node }} went down. Check the node immediately. Severity : Critical Resolution : Contact Red Hat support Procedure : Check which node stopped functioning and its cause. Take appropriate actions to recover the node. If node cannot be recovered: See Replacing storage nodes for Red Hat OpenShift Data Foundation Contact Red Hat support . Name : CephClusterErrorState Message : Storage cluster is in error state Description : Storage cluster is in error state for more than 10m. Severity : Critical Resolution : Contact Red Hat support Procedure : Check for alerts and operator status. If the issue cannot be identified, download log files and diagnostic information using must-gather . Open a Support Ticket with Red Hat Support with an attachment of the output of must-gather. Name : CephClusterWarningState Message : Storage cluster is in degraded state Description : Storage cluster is in warning state for more than 10m. Severity : Warning Resolution : Contact Red Hat support Procedure : Check for alerts and operator status. If the issue cannot be identified, download log files and diagnostic information using must-gather . Open a Support Ticket with Red Hat Support with an attachment of the output of must-gather. Name : CephDataRecoveryTakingTooLong Message : Data recovery is slow Description : Data recovery has been active for too long. Severity : Warning Resolution : Contact Red Hat support Name : CephOSDDiskNotResponding Message : Disk not responding Description : Disk device {{ USDlabels.device }} not responding, on host {{ USDlabels.host }}. Severity : Critical Resolution : Contact Red Hat support Name : CephOSDDiskUnavailable Message : Disk not accessible Description : Disk device {{ USDlabels.device }} not accessible on host {{ USDlabels.host }}. Severity : Critical Resolution : Contact Red Hat support Name : CephPGRepairTakingTooLong Message : Self heal problems detected Description : Self heal operations taking too long. Severity : Warning Resolution : Contact Red Hat support Name : CephMonHighNumberOfLeaderChanges Message : Storage Cluster has seen many leader changes recently. Description : 'Ceph Monitor "{{ USDlabels.job }}": instance {{ USDlabels.instance }} has seen {{ USDvalue printf "%.2f" }} leader changes per minute recently.' Severity : Warning Resolution : Contact Red Hat support Name : CephMonQuorumAtRisk Message : Storage quorum at risk Description : Storage cluster quorum is low. Severity : Critical Resolution : Contact Red Hat support Name : ClusterObjectStoreState Message : Cluster Object Store is in an unhealthy state. Check Ceph cluster health . Description : Cluster Object Store is in an unhealthy state for more than 15s. Check Ceph cluster health . Severity : Critical Resolution : Contact Red Hat support Procedure : Check the CephObjectStore CR instance. Contact Red Hat support . Name : CephOSDFlapping Message : Storage daemon osd.x has restarted 5 times in the last 5 minutes. Check the pod events or Ceph status to find out the cause . Description : Storage OSD restarts more than 5 times in 5 minutes . Severity : Critical Resolution : Contact Red Hat support Name : OdfPoolMirroringImageHealth Message : Mirroring image(s) (PV) in the pool <pool-name> are in Warning state for more than a 1m. Mirroring might not work as expected. Description : Disaster recovery is failing for one or a few applications. Severity : Warning Resolution : Contact Red Hat support Name : OdfMirrorDaemonStatus Message : Mirror daemon is unhealthy . Description : Disaster recovery is failing for the entire cluster. Mirror daemon is in an unhealthy status for more than 1m. Mirroring on this cluster is not working as expected. Severity : Critical Resolution : Contact Red Hat support 7.2. Resolving cluster health issues There is a finite set of possible health messages that a Red Hat Ceph Storage cluster can raise that show in the OpenShift Data Foundation user interface. These are defined as health checks which have unique identifiers. The identifier is a terse pseudo-human-readable string that is intended to enable tools to make sense of health checks, and present them in a way that reflects their meaning. Click the health code below for more information and troubleshooting. Health code Description MON_DISK_LOW One or more Ceph Monitors are low on disk space. 7.2.1. MON_DISK_LOW This alert triggers if the available space on the file system storing the monitor database as a percentage, drops below mon_data_avail_warn (default: 15%). This may indicate that some other process or user on the system is filling up the same file system used by the monitor. It may also indicate that the monitor's database is large. Note The paths to the file system differ depending on the deployment of your mons. You can find the path to where the mon is deployed in storagecluster.yaml . Example paths: Mon deployed over PVC path: /var/lib/ceph/mon Mon deployed over hostpath: /var/lib/rook/mon In order to clear up space, view the high usage files in the file system and choose which to delete. To view the files, run: Replace <path-in-the-mon-node> with the path to the file system where mons are deployed. 7.3. Resolving cluster alerts There is a finite set of possible health alerts that a Red Hat Ceph Storage cluster can raise that show in the OpenShift Data Foundation user interface. These are defined as health alerts which have unique identifiers. The identifier is a terse pseudo-human-readable string that is intended to enable tools to make sense of health checks, and present them in a way that reflects their meaning. Click the health alert for more information and troubleshooting. Table 7.1. Types of cluster health alerts Health alert Overview CephClusterCriticallyFull Storage cluster utilization has crossed 80%. CephClusterErrorState Storage cluster is in an error state for more than 10 minutes. CephClusterNearFull Storage cluster is nearing full capacity. Data deletion or cluster expansion is required. CephClusterReadOnly Storage cluster is read-only now and needs immediate data deletion or cluster expansion. CephClusterWarningState Storage cluster is in a warning state for more than 10 mins. CephDataRecoveryTakingTooLong Data recovery has been active for too long. CephMdsCacheUsageHigh Ceph metadata service (MDS) cache usage for the MDS daemon has exceeded 95% of the mds_cache_memory_limit . CephMdsCpuUsageHigh Ceph MDS CPU usage for the MDS daemon has exceeded the threshold for adequate performance. CephMdsMissingReplicas Minimum required replicas for storage metadata service not available. Might affect the working of the storage cluster. CephMgrIsAbsent Ceph Manager has disappeared from Prometheus target discovery. CephMgrIsMissingReplicas Ceph manager is missing replicas. Thispts health status reporting and will cause some of the information reported by the ceph status command to be missing or stale. In addition, the Ceph manager is responsible for a manager framework aimed at expanding the existing capabilities of Ceph. CephMonHighNumberOfLeaderChanges The Ceph monitor leader is being changed an unusual number of times. CephMonQuorumAtRisk Storage cluster quorum is low. CephMonQuorumLost The number of monitor pods in the storage cluster are not enough. CephMonVersionMismatch There are different versions of Ceph Mon components running. CephNodeDown A storage node went down. Check the node immediately. The alert should contain the node name. CephOSDCriticallyFull Utilization of back-end Object Storage Device (OSD) has crossed 80%. Free up some space immediately or expand the storage cluster or contact support. CephOSDDiskNotResponding A disk device is not responding on one of the hosts. CephOSDDiskUnavailable A disk device is not accessible on one of the hosts. CephOSDFlapping Ceph storage OSD flapping. CephOSDNearFull One of the OSD storage devices is nearing full. CephOSDSlowOps OSD requests are taking too long to process. CephOSDVersionMismatch There are different versions of Ceph OSD components running. CephPGRepairTakingTooLong Self-healing operations are taking too long. CephPoolQuotaBytesCriticallyExhausted Storage pool quota usage has crossed 90%. CephPoolQuotaBytesNearExhaustion Storage pool quota usage has crossed 70%. OSDCPULoadHigh CPU usage in the OSD container on a specific pod has exceeded 80%, potentially affecting the performance of the OSD. PersistentVolumeUsageCritical Persistent Volume Claim usage has exceeded more than 85% of its capacity. PersistentVolumeUsageNearFull Persistent Volume Claim usage has exceeded more than 75% of its capacity. 7.3.1. CephClusterCriticallyFull Meaning Storage cluster utilization has crossed 80% and will become read-only at 85%. Your Ceph cluster will become read-only once utilization crosses 85%. Free up some space or expand the storage cluster immediately. It is common to see alerts related to Object Storage Device (OSD) full or near full prior to this alert. Impact High Diagnosis Scaling storage Depending on the type of cluster, you need to add storage devices, nodes, or both. For more information, see the Scaling storage guide . Mitigation Deleting information If it is not possible to scale up the cluster, you need to delete information to free up some space. 7.3.2. CephClusterErrorState Meaning This alert reflects that the storage cluster is in ERROR state for an unacceptable amount of time and thispts the storage availability. Check for other alerts that would have triggered prior to this one and troubleshoot those alerts first. Impact Critical Diagnosis pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. If the basic health of the running pods, node affinity and resource availability on the nodes are verified, run the Ceph tools to get the status of the storage components. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.3. CephClusterNearFull Meaning Storage cluster utilization has crossed 75% and will become read-only at 85%. Free up some space or expand the storage cluster. Impact Critical Diagnosis Scaling storage Depending on the type of cluster, you need to add storage devices, nodes, or both. For more information, see the Scaling storage guide . Mitigation Deleting information If it is not possible to scale up the cluster, you need to delete information in order to free up some space. 7.3.4. CephClusterReadOnly Meaning Storage cluster utilization has crossed 85% and will become read-only now. Free up some space or expand the storage cluster immediately. Impact Critical Diagnosis Scaling storage Depending on the type of cluster, you need to add storage devices, nodes, or both. For more information, see the Scaling storage guide . Mitigation Deleting information If it is not possible to scale up the cluster, you need to delete information in order to free up some space. 7.3.5. CephClusterWarningState Meaning This alert reflects that the storage cluster has been in a warning state for an unacceptable amount of time. While the storage operations will continue to function in this state, it is recommended to fix the errors so that the cluster does not get into an error state. Check for other alerts that might have triggered prior to this one and troubleshoot those alerts first. Impact High Diagnosis pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.6. CephDataRecoveryTakingTooLong Meaning Data recovery is slow. Check whether all the Object Storage Devices (OSDs) are up and running. Impact High Diagnosis pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.7. CephMdsCacheUsageHigh Meaning When the storage metadata service (MDS) cannot keep its cache usage under the target threshold specified by mds_health_cache_threshold , or 150% of the cache limit set by mds_cache_memory_limit , the MDS sends a health alert to the monitors indicating the cache is too large. As a result, the MDS related operations become slow. Impact High Diagnosis The MDS tries to stay under a reservation of the mds_cache_memory_limit by trimming unused metadata in its cache and recalling cached items in the client caches. It is possible for the MDS to exceed this limit due to slow recall from clients as a result of multiple clients accesing the files. Mitigation Make sure you have enough memory provisioned for MDS cache. Memory resources for the MDS pods need to be updated in the ocs-storageCluster in order to increase the mds_cache_memory_limit . Run the following command to set the memory of MDS pods, for example, 16GB: OpenShift Data Foundation automatically sets mds_cache_memory_limit to half of the MDS pod memory limit. If the memory is set to 8GB using the command, then the operator sets the MDS cache memory limit to 4GB. 7.3.8. CephMdsCpuUsageHigh Meaning The storage metadata service (MDS) serves filesystem metadata. The MDS is crucial for any file creation, rename, deletion, and update operations. MDS by default is allocated two or three CPUs. This does not cause issues as long as there are not too many metadata operations. When the metadata operation load increases enough to trigger this alert, it means the default CPU allocation is unable to cope with load. You need to increase the CPU allocation or run multiple active MDS servers. Impact High Diagnosis Click Workloads Pods . Select the corresponding MDS pod and click on the Metrics tab. There you will see the allocated and used CPU. By default, the alert is fired if the used CPU is 67% of allocated CPU for 6 hours. If this is the case, follow the steps in the mitigation section. Mitigation You need to either increase the allocated CPU or run multiple active MDS. Use the following command to set the number of allocated CPU for MDS, for example, 8: In order to run multiple active MDS servers, use the following command: Make sure you have enough CPU provisioned for MDS depending on the load. Important Always increase the activeMetadataServers by 1 . The scaling of activeMetadataServers works only if you have more than one PV. If there is only one PV that is causing CPU load, look at increasing the CPU resource as described above. 7.3.9. CephMdsMissingReplicas Meaning Minimum required replicas for the storage metadata service (MDS) are not available. MDS is responsible for filing metadata. Degradation of the MDS service can affect how the storage cluster works (related to the CephFS storage class) and should be fixed as soon as possible. Impact High Diagnosis pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.10. CephMgrIsAbsent Meaning Not having a Ceph manager running the monitoring of the cluster. Persistent Volume Claim (PVC) creation and deletion requests should be resolved as soon as possible. Impact High Diagnosis Verify that the rook-ceph-mgr pod is failing, and restart if necessary. If the Ceph mgr pod restart fails, follow the general pod troubleshooting to resolve the issue. Verify that the Ceph mgr pod is failing: Describe the Ceph mgr pod for more details: <pod_name> Specify the rook-ceph-mgr pod name from the step. Analyze the errors related to resource issues. Delete the pod, and wait for the pod to restart: Follow these steps for general pod troubleshooting: pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.11. CephMgrIsMissingReplicas Meaning To resolve this alert, you need to determine the cause of the disappearance of the Ceph manager and restart if necessary. Impact High Diagnosis pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.12. CephMonHighNumberOfLeaderChanges Meaning In a Ceph cluster there is a redundant set of monitor pods that store critical information about the storage cluster. Monitor pods synchronize periodically to obtain information about the storage cluster. The first monitor pod to get the most updated information becomes the leader, and the other monitor pods will start their synchronization process after asking the leader. A problem in network connection or another kind of problem in one or more monitor pods produces an unusual change of the leader. This situation can negatively affect the storage cluster performance. Impact Medium Important Check for any network issues. If there is a network issue, you need to escalate to the OpenShift Data Foundation team before you proceed with any of the following troubleshooting steps. Diagnosis Print the logs of the affected monitor pod to gather more information about the issue: <rook-ceph-mon-X-yyyy> Specify the name of the affected monitor pod. Alternatively, use the Openshift Web console to open the logs of the affected monitor pod. More information about possible causes is reflected in the log. Perform the general pod troubleshooting steps: pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.13. CephMonQuorumAtRisk Meaning Multiple MONs work together to provide redundancy. Each of the MONs keeps a copy of the metadata. The cluster is deployed with 3 MONs, and requires 2 or more MONs to be up and running for quorum and for the storage operations to run. If quorum is lost, access to data is at risk. Impact High Diagnosis Restore the Ceph MON Quorum. For more information, see Restoring ceph-monitor quorum in OpenShift Data Foundation in the Troubleshooting guide . If the restoration of the Ceph MON Quorum fails, follow the general pod troubleshooting to resolve the issue. Perform the following for general pod troubleshooting: pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.14. CephMonQuorumLost Meaning In a Ceph cluster there is a redundant set of monitor pods that store critical information about the storage cluster. Monitor pods synchronize periodically to obtain information about the storage cluster. The first monitor pod to get the most updated information becomes the leader, and the other monitor pods will start their synchronization process after asking the leader. A problem in network connection or another kind of problem in one or more monitor pods produces an unusual change of the leader. This situation can negatively affect the storage cluster performance. Impact High Important Check for any network issues. If there is a network issue, you need to escalate to the OpenShift Data Foundation team before you proceed with any of the following troubleshooting steps. Diagnosis Restore the Ceph MON Quorum. For more information, see Restoring ceph-monitor quorum in OpenShift Data Foundation in the Troubleshooting guide . If the restoration of the Ceph MON Quorum fails, follow the general pod troubleshooting to resolve the issue. Alternatively, perform general pod troubleshooting: pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.15. CephMonVersionMismatch Meaning Typically this alert triggers during an upgrade that is taking a long time. Impact Medium Diagnosis Check the ocs-operator subscription status and the operator pod health to check if an operator upgrade is in progress. Check the ocs-operator subscription health. The status condition types are CatalogSourcesUnhealthy , InstallPlanMissing , InstallPlanPending , and InstallPlanFailed . The status for each type should be False . Example output: The example output shows a False status for type CatalogSourcesUnHealthly , which means that the catalog sources are healthy. Check the OCS operator pod status to see if there is an OCS operator upgrading in progress. If you determine that the `ocs-operator`is in progress, wait for 5 mins and this alert should resolve itself. If you have waited or see a different error status condition, continue troubleshooting. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.16. CephNodeDown Meaning A node running Ceph pods is down. While storage operations will continue to function as Ceph is designed to deal with a node failure, it is recommended to resolve the issue to minimize the risk of another node going down and affecting storage functions. Impact Medium Diagnosis List all the pods that are running and failing: Important Ensure that you meet the OpenShift Data Foundation resource requirements so that the Object Storage Device (OSD) pods are scheduled on the new node. This may take a few minutes as the Ceph cluster recovers data for the failing but now recovering OSD. To watch this recovery in action, ensure that the OSD pods are correctly placed on the new worker node. Check if the OSD pods that were previously failing are now running: If the previously failing OSD pods have not been scheduled, use the describe command and check the events for reasons the pods were not rescheduled. Describe the events for the failing OSD pod: Find the one or more failing OSD pods: In the events section look for the failure reasons, such as the resources are not being met. In addition, you may use the rook-ceph-toolbox to watch the recovery. This step is optional, but is helpful for large Ceph clusters. To access the toolbox, run the following command: From the rsh command prompt, run the following, and watch for "recovery" under the io section: Determine if there are failed nodes. Get the list of worker nodes, and check for the node status: Describe the node which is of the NotReady status to get more information about the failure: Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.17. CephOSDCriticallyFull Meaning One of the Object Storage Devices (OSDs) is critically full. Expand the cluster immediately. Impact High Diagnosis Deleting data to free up storage space You can delete data, and the cluster will resolve the alert through self healing processes. Important This is only applicable to OpenShift Data Foundation clusters that are near or full but not in read-only mode. Read-only mode prevents any changes that include deleting data, that is, deletion of Persistent Volume Claim (PVC), Persistent Volume (PV) or both. Expanding the storage capacity Current storage size is less than 1 TB You must first assess the ability to expand. For every 1 TB of storage added, the cluster needs to have 3 nodes each with a minimum available 2 vCPUs and 8 GiB memory. You can increase the storage capacity to 4 TB via the add-on and the cluster will resolve the alert through self healing processes. If the minimum vCPU and memory resource requirements are not met, you need to add 3 additional worker nodes to the cluster. Mitigation If your current storage size is equal to 4 TB, contact Red Hat support. Optional: Run the following command to gather the debugging information for the Ceph cluster: 7.3.18. CephOSDDiskNotResponding Meaning A disk device is not responding. Check whether all the Object Storage Devices (OSDs) are up and running. Impact Medium Diagnosis pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. If the basic health of the running pods, node affinity and resource availability on the nodes are verified, run the Ceph tools to get the status of the storage components. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.19. CephOSDDiskUnavailable Meaning A disk device is not accessible on one of the hosts and its corresponding Object Storage Device (OSD) is marked out by the Ceph cluster. This alert is raised when a Ceph node fails to recover within 10 minutes. Impact High Diagnosis Determine the failed node Get the list of worker nodes, and check for the node status: Describe the node which is of NotReady status to get more information on the failure: 7.3.20. CephOSDFlapping Meaning A storage daemon has restarted 5 times in the last 5 minutes. Check the pod events or Ceph status to find out the cause. Impact High Diagnosis Follow the steps in the Flapping OSDs section of the Red Hat Ceph Storage Troubleshooting Guide. Alternatively, follow the steps for general pod troubleshooting: pod status: pending Check for resource issues, pending Persistent Volume Claims (PVCs), node assignment, and kubelet problems: Set MYPOD as the variable for the pod that is identified as the problem pod: <pod_name> Specify the name of the pod that is identified as the problem pod. Look for the resource limitations or pending PVCs. Otherwise, check for the node assignment: pod status: NOT pending, running, but NOT ready Check the readiness probe: pod status: NOT pending, but NOT running Check for application or image issues: Important If a node was assigned, check the kubelet on the node. If the basic health of the running pods, node affinity and resource availability on the nodes are verified, run the Ceph tools to get the status of the storage components. Mitigation Debugging log information This step is optional. Run the following command to gather the debugging information for the Ceph cluster: 7.3.21. CephOSDNearFull Meaning Utilization of back-end storage device Object Storage Device (OSD) has crossed 75% on a host. Impact High Mitigation Free up some space in the cluster, expand the storage cluster, or contact Red Hat support. For more information on scaling storage, see the Scaling storage guide . 7.3.22. CephOSDSlowOps Meaning An Object Storage Device (OSD) with slow requests is every OSD that is not able to service the I/O operations per second (IOPS) in the queue within the time defined by the osd_op_complaint_time parameter. By default, this parameter is set to 30 seconds. Impact Medium Diagnosis More information about the slow requests can be obtained using the Openshift console. Access the OSD pod terminal, and run the following commands: Note The number of the OSD is seen in the pod name. For example, in rook-ceph-osd-0-5d86d4d8d4-zlqkx , <0> is the OSD. Mitigation The main causes of the OSDs having slow requests are: Problems with the underlying hardware or infrastructure, such as, disk drives, hosts, racks, or network switches. Use the Openshift monitoring console to find the alerts or errors about cluster resources. This can give you an idea about the root cause of the slow operations in the OSD. Problems with the network. These problems are usually connected with flapping OSDs. See the Flapping OSDs section of the Red Hat Ceph Storage Troubleshooting Guide If it is a network issue, escalate to the OpenShift Data Foundation team System load. Use the Openshift console to review the metrics of the OSD pod and the node which is running the OSD. Adding or assigning more resources can be a possible solution. 7.3.23. CephOSDVersionMismatch Meaning Typically this alert triggers during an upgrade that is taking a long time. Impact Medium Diagnosis Check the ocs-operator subscription status and the operator pod health to check if an operator upgrade is in progress. Check the ocs-operator subscription health. The status condition types are CatalogSourcesUnhealthy , InstallPlanMissing , InstallPlanPending , and InstallPlanFailed . The status for each type should be False . Example output: The example output shows a False status for type CatalogSourcesUnHealthly , which means that the catalog sources are healthy. Check the OCS operator pod status to see if there is an OCS operator upgrading in progress. If you determine that the `ocs-operator`is in progress, wait for 5 mins and this alert should resolve itself. If you have waited or see a different error status condition, continue troubleshooting. 7.3.24. CephPGRepairTakingTooLong Meaning Self-healing operations are taking too long. Impact High Diagnosis Check for inconsistent Placement Groups (PGs), and repair them. For more information, see the Red Hat Knowledgebase solution Handle Inconsistent Placement Groups in Ceph . 7.3.25. CephPoolQuotaBytesCriticallyExhausted Meaning One or more pools has reached, or is very close to reaching, its quota. The threshold to trigger this error condition is controlled by the mon_pool_quota_crit_threshold configuration option. Impact High Mitigation Adjust the pool quotas. Run the following commands to fully remove or adjust the pool quotas up or down: Setting the quota value to 0 will disable the quota. 7.3.26. CephPoolQuotaBytesNearExhaustion Meaning One or more pools is approaching a configured fullness threshold. One threshold that can trigger this warning condition is the mon_pool_quota_warn_threshold configuration option. Impact High Mitigation Adjust the pool quotas. Run the following commands to fully remove or adjust the pool quotas up or down: Setting the quota value to 0 will disable the quota. 7.3.27. OSDCPULoadHigh Meaning OSD is a critical component in Ceph storage, responsible for managing data placement and recovery. High CPU usage in the OSD container suggests increased processing demands, potentially leading to degraded storage performance. Impact High Diagnosis Navigate to the Kubernetes dashboard or equivalent. Access the Workloads section and select the relevant pod associated with the OSD alert. Click the Metrics tab to view CPU metrics for the OSD container. Verify that the CPU usage exceeds 80% over a significant period (as specified in the alert configuration). Mitigation If the OSD CPU usage is consistently high, consider taking the following steps: Evaluate the overall storage cluster performance and identify the OSDs contributing to high CPU usage. Increase the number of OSDs in the cluster by adding more new storage devices in the existing nodes or adding new nodes with new storage devices. Review the Scaling storage4 for instructions to help distribute the load and improve overall system performance. 7.3.28. PersistentVolumeUsageCritical Meaning A Persistent Volume Claim (PVC) is nearing its full capacity and may lead to data loss if not attended to timely. Impact High Mitigation Expand the PVC size to increase the capacity. Log in to the OpenShift Web Console. Click Storage PersistentVolumeClaim . Select openshift-storage from the Project drop-down list. On the PVC you want to expand, click Action menu (...) Expand PVC . Update the Total size to the desired size. Click Expand . Alternatively, you can delete unnecessary data that may be taking up space. 7.3.29. PersistentVolumeUsageNearFull Meaning A Persistent Volume Claim (PVC) is nearing its full capacity and may lead to data loss if not attended to timely. Impact High Mitigation Expand the PVC size to increase the capacity. Log in to the OpenShift Web Console. Click Storage PersistentVolumeClaim . Select openshift-storage from the Project drop-down list. On the PVC you want to expand, click Action menu (...) Expand PVC . Update the Total size to the desired size. Click Expand . Alternatively, you can delete unnecessary data that may be taking up space. 7.4. Finding the error code of an unhealthy bucket Procedure In the OpenShift Web Console, click Storage Object Storage . Click the Object Bucket Claims tab. Look for the object bucket claims (OBCs) that are not in Bound state and click on it. Click the Events tab and do one of the following: Look for events that might hint you about the current state of the bucket. Click the YAML tab and look for related errors around the status and mode sections of the YAML. If the OBC is in Pending state. the error might appear in the product logs. However, in this case, it is recommended to verify that all the variables provided are accurate. 7.5. Finding the error code of an unhealthy namespace store resource Procedure In the OpenShift Web Console, click Storage Object Storage . Click the Namespace Store tab. Look for the namespace store resources that are not in Bound state and click on it. Click the Events tab and do one of the following: Look for events that might hint you about the current state of the resource. Click the YAML tab and look for related errors around the status and mode sections of the YAML. 7.6. Recovering pods When a first node (say NODE1 ) goes to NotReady state because of some issue, the hosted pods that are using PVC with ReadWriteOnce (RWO) access mode try to move to the second node (say NODE2 ) but get stuck due to multi-attach error. In such a case, you can recover MON, OSD, and application pods by using the following steps. Procedure Power off NODE1 (from AWS or vSphere side) and ensure that NODE1 is completely down. Force delete the pods on NODE1 by using the following command: 7.7. Recovering from EBS volume detach When an OSD or MON elastic block storage (EBS) volume where the OSD disk resides is detached from the worker Amazon EC2 instance, the volume gets reattached automatically within one or two minutes. However, the OSD pod gets into a CrashLoopBackOff state. To recover and bring back the pod to Running state, you must restart the EC2 instance. 7.8. Enabling and disabling debug logs for rook-ceph-operator Enable the debug logs for the rook-ceph-operator to obtain information about failures that help in troubleshooting issues. Procedure Enabling the debug logs Edit the configmap of the rook-ceph-operator. Add the ROOK_LOG_LEVEL: DEBUG parameter in the rook-ceph-operator-config yaml file to enable the debug logs for rook-ceph-operator. Now, the rook-ceph-operator logs consist of the debug information. Disabling the debug logs Edit the configmap of the rook-ceph-operator. Add the ROOK_LOG_LEVEL: INFO parameter in the rook-ceph-operator-config yaml file to disable the debug logs for rook-ceph-operator. 7.9. Resolving low Ceph monitor count alert The CephMonLowNumber alert is displayed in the notification panel or Alert Center of the OpenShift Web Console to indicate the low number of Ceph monitor count when your internal mode deployment has five or more nodes, racks, or rooms, and when there are five or more number of failure domains in the deployment. You can increase the Ceph monitor count to improve the availability of cluster. Procedure In the CephMonLowNumber alert of the notification panel or Alert Center of OpenShift Web Console, click Configure . In the Configure Ceph Monitor pop up, click Update count. In the pop up, the recommended monitor count depending on the number of failure zones is shown. In the Configure CephMon pop up, update the monitor count value based on the recommended value and click Save changes . 7.10. Troubleshooting unhealthy blocklisted nodes 7.10.1. ODFRBDClientBlocked Meaning This alert indicates that an RADOS Block Device (RBD) client might be blocked by Ceph on a specific node within your Kubernetes cluster. The blocklisting occurs when the ocs_rbd_client_blocklisted metric reports a value of 1 for the node. Additionally, there are pods in a CreateContainerError state on the same node. The blocklisting can potentially result in the filesystem for the Persistent Volume Claims (PVCs) using RBD becoming read-only. It is crucial to investigate this alert to prevent any disruption to your storage cluster. Impact High Diagnosis The blocklisting of an RBD client can occur due to several factors, such as network or cluster slowness. In certain cases, the exclusive lock contention among three contending clients (workload, mirror daemon, and manager/scheduler) can lead to the blocklist. Mitigation Taint the blocklisted node: In Kubernetes, consider tainting the node that is blocklisted to trigger the eviction of pods to another node. This approach relies on the assumption that the unmounting/unmapping process progresses gracefully. Once the pods have been successfully evicted, the blocklisted node can be untainted, allowing the blocklist to be cleared. The pods can then be moved back to the untainted node. Reboot the blocklisted node: If tainting the node and evicting the pods do not resolve the blocklisting issue, a reboot of the blocklisted node can be attempted. This step may help alleviate any underlying issues causing the blocklist and restore normal functionality. Important Investigating and resolving the blocklist issue promptly is essential to avoid any further impact on the storage cluster.

Commands:
du -a <path-in-the-mon-node> |sort -n -r |head -n10
oc project openshift-storage
oc get pod | grep rook-ceph
Examine the output for a rook-ceph that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc project openshift-storage
get pod | grep {ceph-component}
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc project openshift-storage
get pod | grep rook-ceph-osd
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc patch -n openshift-storage storagecluster ocs-storagecluster --type merge --patch '{"spec": {"resources": {"mds": {"limits": {"memory": "16Gi"},"requests": {"memory": "16Gi"}}}}}'
patch -n openshift-storage storagecluster ocs-storagecluster --type merge --patch '{"spec": {"resources": {"mds": {"limits": {"cpu": "8"}, "requests": {"cpu": "8"}}}}}'
patch -n openshift-storage storagecluster ocs-storagecluster --type merge --patch '{"spec": {"managedResources": {"cephFilesystems":{"activeMetadataServers": 2}}}}'
oc project openshift-storage
get pod | grep rook-ceph-mds
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc get pods | grep mgr
oc describe pods/ <pod_name>
oc get pods | grep mgr
oc project openshift-storage
get pod | grep rook-ceph-mgr
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc project openshift-storage
get pod | grep rook-ceph-mgr
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc logs <rook-ceph-mon-X-yyyy> -n openshift-storage
oc project openshift-storage
get pod | grep {ceph-component}
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc project openshift-storage
get pod | grep rook-ceph-mon
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc project openshift-storage
get pod | grep {ceph-component}
Examine the output for a {ceph-component} that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc get sub USD(oc get pods -n openshift-storage | grep -v ocs-operator) -n openshift-storage -o json | jq .status.conditions
lastTransitionTime: 2021-01-26T19:21:37Z
message: all available catalogsources are healthy
reason: AllCatalogSourcesHealthy
status: False
type: CatalogSourcesUnhealthy
oc get pod -n openshift-storage | grep ocs-operator OCSOP=USD(oc get pod -n openshift-storage -o custom-columns=POD:.metadata.name --no-headers | grep ocs-operator) echo USDOCSOP oc get pod/USD{OCSOP} -n openshift-storage oc describe pod/USD{OCSOP} -n openshift-storage
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
-n openshift-storage get pods
-n openshift-storage get pods
-n openshift-storage get pods | grep osd
-n openshift-storage describe pods/<osd_podname_ from_the_ previous step>
TOOLS_POD=USD(oc get pods -n openshift-storage -l app=rook-ceph-tools -o name) rsh -n openshift-storage USDTOOLS_POD
ceph status
get nodes --selector='node-role.kubernetes.io/worker','!node-role.kubernetes.io/infra'
describe node <node_name>
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
oc project openshift-storage
oc get pod | grep rook-ceph
Examine the output for a rook-ceph that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
get nodes --selector='node-role.kubernetes.io/worker','!node-role.kubernetes.io/infra'
describe node <node_name>
oc project openshift-storage
oc get pod | grep rook-ceph
Examine the output for a rook-ceph that is in the pending state, not running or not ready MYPOD= <pod_name>
oc get pod/USD{MYPOD} -o wide
oc describe pod/USD{MYPOD}
oc logs pod/USD{MYPOD}
oc adm must-gather --image=registry.redhat.io/odf4/odf-must-gather-rhel9:v4.15
ceph daemon osd.<id> ops
ceph daemon osd.<id> dump_historic_ops
oc get sub USD(oc get pods -n openshift-storage | grep -v ocs-operator) -n openshift-storage -o json | jq .status.conditions
lastTransitionTime: 2021-01-26T19:21:37Z
message: all available catalogsources are healthy
reason: AllCatalogSourcesHealthy
status: False
type: CatalogSourcesUnhealthy
oc get pod -n openshift-storage | grep ocs-operator OCSOP=USD(oc get pod -n openshift-storage -o custom-columns=POD:.metadata.name --no-headers | grep ocs-operator) echo USDOCSOP oc get pod/USD{OCSOP} -n openshift-storage oc describe pod/USD{OCSOP} -n openshift-storage
ceph osd pool set-quota <pool> max_bytes <bytes>
ceph osd pool set-quota <pool> max_objects <objects>
ceph osd pool set-quota <pool> max_bytes <bytes>
ceph osd pool set-quota <pool> max_objects <objects>
oc delete pod <pod-name> --grace-period=0 --force
oc edit configmap rook-ceph-operator-config
... data: # The logging level for the operator: INFO | DEBUG ROOK_LOG_LEVEL: DEBUG
oc edit configmap rook-ceph-operator-config
... data: # The logging level for the operator: INFO | DEBUG ROOK_LOG_LEVEL: INFO