### Understand the alert

This alert indicates that there is an increase in the number of Docker or runtime operation errors in your Kubernetes cluster's kubelet. A high number of errors can affect the overall stability and performance of your cluster.

### What are Docker or runtime operation errors?

Docker or runtime operation errors are errors that occur while the kubelet is managing container-related operations. These errors can be related to creating, starting, stopping, or deleting containers in your Kubernetes cluster.

### Troubleshoot the alert

1. Check kubelet logs:

   You need to inspect the kubelet logs of the affected nodes to find more information about the reported errors. SSH into the affected node and use the following command to stream the kubelet logs:

   ```
   journalctl -u kubelet -f
   ```

   Look for any error messages or patterns that could indicate a problem.

2. Inspect containers' logs:

   If an error is related to a specific container, you can inspect the logs of that container using the following command:

   ```
   kubectl logs <container_name> -n <namespace>
   ```

   Replace `<container_name>` and `<namespace>` with the appropriate values.

3. Check Docker or runtime logs:

   On the affected node, check Docker or container runtime logs for any issues:

   - For Docker, use: `journalctl -u docker`
   - For containerd, use: `journalctl -u containerd`
   - For CRI-O, use: `journalctl -u crio`

4. Examine Kubernetes events:

   Run the following command to see recent events in your cluster:

   ```
   kubectl get events
   ```

   Look for any error messages or patterns that could indicate a kubelet or container-related problem.

5. Verify resource allocation:

   Ensure that the node has enough resources available (such as CPU, memory, and disk space) for the containers running on it. You can use commands like `kubectl describe node <node_name>` or monitor your cluster resources using Netdata.

6. Investigate other issues:

   If the above steps didn't reveal the cause of the errors, investigate other potential causes, such as network issues, filesystem corruption, hardware problems, or misconfigurations.

### Useful resources

1. [Kubernetes Debugging and Troubleshooting](https://kubernetes.io/docs/tasks/debug-application-cluster/debug-cluster/)
2. [Troubleshoot the Kubelet](https://kubernetes.io/docs/tasks/debug-application-cluster/debug-application-introspection/)
3. [Access Clusters Using the Kubernetes API](https://kubernetes.io/docs/tasks/administer-cluster/access-cluster-api/)