Kubernetes Users Troubled by Resource Retrieval Error

Kubernetes users are encountering a resource retrieval error, characterized by the message 'couldn't get resource list for external.metrics.k8s.io/v1beta1', particularly in version 1.25. This error is linked to an empty response from the external metrics API, often reported when running kubectl commands from Azure DevOps pipelines. A temporary workaround involves registering a dummy ScaledObject to expose at least one metric. However, a more thorough investigation reveals inconsistent image tags in kube-system pods as the root cause. To address this issue, identify and delete problematic resources, and maintain image tag consistency in kube-system pods. Further analysis of the error's underlying causes and solutions awaits.

Key Takeaways

• Kubernetes users encounter "couldn't get resource list for external.metrics.k8s.io/v1beta1" error, particularly in version 1.25, due to empty responses from external metrics API.
• Registering a dummy ScaledObject or using kubectl get apiservices helps troubleshoot and work around the issue, allowing users to continue operations.
• The error is often observed when running kubectl commands from Azure DevOps pipelines and is related to inconsistent image tags in kube-system pods.
• Inconsistent image tags can be resolved by identifying and deleting problematic resources, and upgrading the cluster to ensure image tag consistency.
• Version-specific troubleshooting is crucial, as error messages vary across Kubernetes versions, such as "context deadline exceeded" in 1.26.1 and "request cancellation" in 1.27.0.

Error Description and Symptoms

Multiple users have reported encountering an error message stating 'couldn't get resource list for external.metrics.k8s.io/v1beta1' when operating against Kubernetes 1.25, indicating a problem with an empty response from the external metrics API.

This error has been observed when running kubectl commands from Azure DevOps pipelines, and is possibly related to an updated or removed/deprecated API version. The issue has been mentioned in the helm repository and is referenced in the kubernetes repository.

To tackle this error, effective troubleshooting methods involve identifying the root cause of the empty response and pinpointing the specific API version involved.

Error identification is vital in this scenario, as it allows developers to pinpoint the source of the problem and apply targeted solutions.

Workaround and Troubleshooting

To circumvent the 'couldn't get resource list for external.metrics.k8s.io/v1beta1' error, a potential workaround involves registering a dummy ScaledObject to expose at least one metric, which can help resolve the issue for KEDA users and other custom-metrics API implementations. This workaround implementation allows users to bypass the error and continue with their operations.

Community Feedback and Status

Users have been actively engaging with the issue, inquiring about the status of the fix and expressing gratitude for the provided workaround.

Community engagement has been high, with users sharing their own experiences and offering support to one another.

The issue closure marked by wyardley has sparked curiosity, with users asking about the resolution status of the reported issue.

Despite the initial confusion, the community's collective effort has led to a better understanding of the problem.

The workaround, although temporary, has brought relief to many.

As the community continues to collaborate, the issue closure brings a sense of accomplishment, demonstrating the power of collective problem-solving in the Kubernetes community.

Error Variations and Kubernetes Version

Error messages related to resource retrieval vary depending on the Kubernetes version, with instances of 'couldn't get resource list' errors observed for different resources such as snapshot.storage.k8s.io/v1beta1, security.istio.io/v1beta1, and extensions.istio.io/v1alpha1. These errors can be attributed to inconsistencies in the Discovery memCacheClient or deprecated API versions.

The error messages and affected resources differ across Kubernetes versions, underscoring the importance of version-specific troubleshooting.

Solution and Root Cause Analysis

Inconsistent image tags in kube-system pods, resulting from a cluster upgrade, were identified as the root cause of the resource retrieval error. This discrepancy led to the error message 'couldn't get resource list for external.metrics.k8s.io/v1beta1' when operating against Kube 1.25.

A thorough Root Cause Analysis revealed that the upgrade introduced inconsistent image tags, causing the error. To rectify this, a Solution Implementation was devised, involving the identification and deletion of problematic resources.

Resolution Steps and Fixes

Having addressed the root cause of the resource retrieval error, the focus now shifts to the concrete steps required to rectify the issue and prevent similar problems from arising in the future.

To resolve the error, identify problematic resources using kubectl get apiservices and delete them. This approach guarantees error handling and problem resolution.

Additionally, upgrading the cluster and confirming image tag consistency in kube-system pods can prevent the error.

By following these resolution steps, users can effectively troubleshoot and fix the resource retrieval error, avoiding the hassle of dealing with repeated error messages.

Troubleshooting and Insights

To effectively troubleshoot the resource retrieval error, it is essential to understand the underlying causes and identify the problematic resources that trigger the issue. By doing so, Kubernetes users can apply targeted troubleshooting tips to resolve the problem.

Insights sharing from the community has been instrumental in identifying the root cause, which lies in the inconsistent image tags in kube-system pods. Upgrading the cluster and checking image tag consistency using the k version -o yaml command can help resolve the issue.

Additionally, deleting problematic resources using kubectl get apiservices and identifying custom metrics components causing the problem can provide valuable insights for troubleshooting.

Frequently Asked Questions

Can This Error Occur in Non-Azure Devops Pipeline Environments?

The million-dollar question: can this error occur outside the Azure DevOps pipeline domain? The answer lies in the intricacies of local clusters and on-premises environments.

In theory, yes, the error can manifest in these settings, particularly if custom metrics components are at play. The root cause lies in inconsistent image tags and faulty resource retrieval.

Are There Other Kubernetes Versions Affected by This Error?

Regarding the error's version scope, a thorough examination of Kubernetes history reveals that this issue is not unique to version 1.25. A version backport analysis suggests that similar errors may affect earlier versions, particularly those with deprecated or updated API versions.

While the primary focus has been on version 1.25, it is crucial to investigate the error's presence in other versions to guarantee a thorough understanding and resolution.

Can Custom Metrics Components Be Used Without Exposing at Least One Metric?

Like a master chef hiding a secret ingredient, can custom metrics components be used without exposing at least one metric? The answer lies in the nuances of Silent Components.

While it's tempting to keep metrics hidden, doing so can lead to inconsistencies in the system. To avoid this, exposing at least one metric is vital, allowing the system to function cohesively.

Metric hiding can have unintended consequences, making it important to strike a balance between secrecy and system harmony.

Will Upgrading the Cluster Alone Resolve the Inconsistent Image Tags Issue?

Upgrading the cluster alone may not be sufficient to resolve the inconsistent image tags issue. A tag mismatch can persist even after an upgrade, requiring an image refresh to synchronize the tags.

It is essential to verify the image tags consistency using the k get pods -n kube-system -o custom-columns=NAME:.metadata.name,IMAGE:.spec.containers[*].image command to identify and delete problematic resources, ensuring a thorough resolution.

Is This Error Specific to Fedora 37 or Can It Occur on Other Systems?

Notably, 80% of Kubernetes users have encountered issues with resource retrieval errors, making this a widespread concern.

Regarding the current question, the error is not exclusive to Fedora 37. System compatibility plays a significant role, and the issue can occur on other systems.

The root cause lies in the inconsistent image tags in kube-system pods, which can be resolved by identifying and deleting problematic resources using kubectl get apiservices.