Longhorn Volume Degraded Alert Troubleshooting Guide For Pvc-ccde79ca-2158-41c8-8507-845825fc161f

This alert indicates a critical issue within your Longhorn storage system. Specifically, the Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f has been identified as Degraded. This situation demands immediate attention as it signifies a potential risk to data availability and application stability. The alert, triggered on July 17, 2025, at 09:23:31 UTC, highlights that the volume has been in a degraded state for more than 10 minutes, further emphasizing the urgency of the matter.

Understanding the Alert

To effectively address this alert, it's crucial to understand the context and implications of a degraded Longhorn volume. Longhorn is a distributed block storage system for Kubernetes, designed to provide persistent storage for stateful applications. A volume in a degraded state implies that one or more replicas of the volume's data are unavailable or have encountered issues. This could be due to various reasons, such as node failures, disk errors, network connectivity problems, or software bugs.

Key components involved in this alert include:

• Volume: pvc-ccde79ca-2158-41c8-8507-845825fc161f - The specific Longhorn volume experiencing the degradation. This volume is associated with a Persistent Volume Claim (PVC).
• PVC: kanister-pvc-q9p8z - The Persistent Volume Claim (PVC) that provisions the degraded Longhorn volume. PVCs are requests for storage by Kubernetes users.
• PVC Namespace: kasten-io - The Kubernetes namespace where the PVC kanister-pvc-q9p8z resides. Namespaces provide a way to divide cluster resources between multiple users.
• Node: hive03 - The Kubernetes node where the Longhorn volume is experiencing issues. Identifying the node helps narrow down the scope of the problem.
• Pod: longhorn-manager-2nsdf - The Longhorn Manager pod running on the affected node. The Longhorn Manager is responsible for managing Longhorn volumes and replicas.
• Longhorn Backend: The Longhorn service responsible for managing the storage backend.

The alert's description clearly states that the Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f on node hive03 has been degraded for more than 10 minutes. This prolonged degraded state increases the risk of data loss and application disruption. The summary reiterates the core issue: the volume is degraded, underscoring the need for immediate action.

Analyzing Common Labels

The common labels associated with this alert provide valuable context for troubleshooting. Let's break down the significance of each label:

• alertname: LonghornVolumeStatusWarning - This label clearly identifies the type of alert, indicating a warning related to the status of a Longhorn volume. It serves as a primary indicator of the issue.
• container: longhorn-manager - This label specifies that the alert originates from the longhorn-manager container, which is a crucial component of the Longhorn system responsible for managing volumes and replicas. This helps pinpoint the source of the alert.
• endpoint: manager - This label indicates that the alert is related to the manager endpoint of the Longhorn system, further narrowing down the potential area of concern.
• instance: 10.42.0.17:9500 - This label provides the specific instance or address of the Longhorn Manager that triggered the alert. This information is useful for identifying the exact component experiencing the issue.
• issue: Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f is Degraded. - This label directly states the problem: the Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f is in a degraded state. This is the core information conveyed by the alert.
• job: longhorn-backend - This label indicates that the alert is related to the Longhorn backend job, which is responsible for managing the storage infrastructure. This helps understand which part of the system is affected.
• namespace: longhorn-system - This label specifies that the alert originates from the longhorn-system namespace, which is where Longhorn's core components are typically deployed. This helps isolate the alert within the Longhorn environment.
• node: hive03 - This label identifies the Kubernetes node (hive03) where the degraded volume is located. This is crucial for pinpointing the physical location of the issue.
• pod: longhorn-manager-2nsdf - This label specifies the Longhorn Manager pod (longhorn-manager-2nsdf) that triggered the alert. This provides more granular information about the specific instance of the Longhorn Manager involved.
• prometheus: kube-prometheus-stack/kube-prometheus-stack-prometheus - This label indicates that the alert was generated by Prometheus, a monitoring and alerting system, specifically from the kube-prometheus-stack. This shows the monitoring infrastructure in use.
• pvc: kanister-pvc-q9p8z - As mentioned earlier, this label identifies the Persistent Volume Claim (kanister-pvc-q9p8z) associated with the degraded volume. This links the storage issue to a specific application or workload.
• pvc_namespace: kasten-io - This label specifies the namespace (kasten-io) where the Persistent Volume Claim is located. This helps in understanding the context of the application using the storage.
• service: longhorn-backend - This label, similar to the job label, indicates that the alert is related to the Longhorn backend service. This reinforces the focus on the storage infrastructure.
• severity: warning - This label indicates the severity of the alert as a warning. While not critical, warnings should be addressed promptly to prevent escalation into more severe issues.
• volume: pvc-ccde79ca-2158-41c8-8507-845825fc161f - This label reiterates the specific Longhorn volume that is degraded, ensuring clarity and consistency.

Investigating Common Annotations

The common annotations provide a human-readable summary and description of the alert, aiding in quick understanding and initial assessment:

• description: Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f on hive03 is Degraded for more than 10 minutes. - This annotation offers a detailed description of the alert, specifying the affected volume, the node where it's located, and the duration of the degraded state. The 10-minute duration highlights the persistence of the issue and the need for prompt action.
• summary: Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f is Degraded - This annotation provides a concise summary of the alert, focusing on the core problem: the volume is degraded. It serves as a quick overview for responders.

Immediate Actions and Troubleshooting Steps

Upon receiving this alert, the following steps should be taken immediately:

1. Acknowledge the Alert: This ensures that the alert is being actively investigated and prevents multiple team members from working on the same issue simultaneously.
2. Identify the Impacted Application: Determine which application or service is using the degraded volume (pvc-ccde79ca-2158-41c8-8507-845825fc161f). This is crucial for assessing the potential impact of the degradation.
3. Check Longhorn UI: Access the Longhorn UI to gain a visual overview of the cluster's health and the status of the degraded volume. The UI provides detailed information about the volume, its replicas, and any potential errors.
4. Examine Longhorn Logs: Review the logs of the Longhorn Manager pod (longhorn-manager-2nsdf) and other relevant Longhorn components on node hive03. Look for error messages, warnings, or any other clues that might indicate the cause of the degradation.
5. Inspect Node Status: Check the status of the node (hive03) using kubectl describe node hive03. Look for any node-level issues, such as disk pressure, network problems, or resource exhaustion.
6. Verify Replica Status: In the Longhorn UI, examine the status of the replicas for the degraded volume. Identify any failed or unhealthy replicas.
7. Investigate Underlying Storage: Check the health and status of the underlying storage on node hive03. This might involve checking disk space, disk I/O, and any hardware-related issues.

Potential Causes and Solutions

Several factors can contribute to a degraded Longhorn volume. Here are some common causes and potential solutions:

• Node Failure: If the node hosting the volume replicas has failed, Longhorn will mark the volume as degraded. In this case, ensure the node is back online and healthy. Longhorn should automatically attempt to rebuild the replicas on other healthy nodes.
• Disk Errors: Disk failures or errors can lead to replica unavailability and volume degradation. Check the disk health on the affected node and consider replacing faulty disks.
• Network Connectivity Issues: Network problems between nodes can prevent replicas from synchronizing, resulting in a degraded volume. Verify network connectivity and firewall rules between Longhorn nodes.
• Resource Exhaustion: Insufficient resources (CPU, memory, disk space) on the node can impact Longhorn's ability to maintain healthy replicas. Ensure the node has adequate resources.
• Longhorn Bugs: Although rare, bugs in Longhorn itself can cause volume degradation. Check for any known issues or updates and consider upgrading Longhorn to the latest stable version.
• Data Corruption: In some cases, data corruption within the volume can lead to degradation. This is a more serious issue that might require data recovery efforts.

Using the Provided Links

The alert includes a link to a Prometheus graph: http://prometheus.gavriliu.com/graph?g0.expr=longhorn_volume_robustness+%3D%3D+2&g0.tab=1. This graph visualizes the longhorn_volume_robustness metric, which indicates the health status of Longhorn volumes. A value of 2 typically corresponds to a degraded state. Analyzing this graph can provide insights into the history of the volume's health and any recent changes.

Conclusion

The LonghornVolumeStatusWarning alert signals a critical issue requiring immediate attention. By understanding the context of the alert, analyzing the common labels and annotations, and following the recommended troubleshooting steps, you can effectively diagnose and resolve the degradation of the Longhorn volume pvc-ccde79ca-2158-41c8-8507-845825fc161f, ensuring the availability and integrity of your data.

Common Labels

Common Annotations

Alerts