How to resolve ImagePullBackOff Issue in Kubernetes Cluster

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Issue Summary

An ImagePullBackOff issue can occur in a Kubernetes (k8s) cluster, which may impact deployments of applications. This article outlines the root cause, resolution steps, and preventive measures to address this issue effectively.

Root Cause

The ImagePullBackOff error is often caused by referencing deprecated image tags in container registries. For instance, the deprecation of Google Container Registry (GCR) as of March 2025 led to applications referencing outdated GCR image tags, resulting in the ImagePullBackOff error.

Affected Components

bold bi: Image tag referenced gcr.io/boldbi/.
bold reports: Image tag referenced gcr.io/boldreports/.

Resolution Steps

To resolve the ImagePullBackOff issue, follow these steps:

Update Image Tags: Modify the image tags in the values.yaml file to point to the new Google Artifact Registry:
- Application A: Update from gcr.io/application-a/ to us-docker.pkg.dev/application-a/application.
- Application B: Update from gcr.io/application-b/ to us-docker.pkg.dev/application-b/images.
Deploy Using Local Helm Repository: Ensure that the applications are deployed using the local source folder Helm deployment. If an upgrade is attempted using a public Helm repository, it may lead to errors. Create the necessary folder structure as per the provided instructions.
Run the Helm Upgrade Command: Execute the following command to ensure the deployment references the local Helm repository with the updated values.yaml file:
```
helm upgrade application-a bold-common -f values.yaml -n application-services
```

Preventive Measures

Ensure that image tags point to the Google Artifact Registry to maintain compatibility with the current infrastructure.
This update is a one-time process, and the issue should not recur as the correct registry is now configured.
To prevent similar issues in the future, always use the local Helm repository when upgrading deployments with the following command:
```
helm upgrade application-a bold-common -f values.yaml -n application-services
```

Conclusion

The ImagePullBackOff issue can be effectively resolved by updating image tags to the Google Artifact Registry and ensuring the correct folder structure for local Helm deployments. Following these steps will help maintain operational stability for applications without disruptions.

Additional References

Kubernetes Helm Documentation

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Written by Poovarasan Kandasamy

Updated:

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