Скачать или смотреть How to Remove Kubernetes Pods Related Files from Your File System

Learn how to effectively free up disk space in Kubernetes after deleting pods, and understand what might be keeping your system from releasing this space.
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Understanding Kubernetes Disk Usage

If you are new to Kubernetes, you may have encountered a situation where you delete pods but still see that your disk space remains unchanged. After using the command kubectl delete pods --all, you might expect the associated files to be cleaned up, but that doesn’t always happen. This can lead to confusion and frustration, especially when your df -h output still shows significant disk usage connected to Kubernetes components.

The Problem: Persistent Disk Usage

After you delete your Kubernetes pods, you may notice that disk usage numbers reported by various commands like df -h still show a high percentage of disk being used. Furthermore, if your pods are rapidly restarting after deletion, this indicates that there are underlying issues causing the disk to be retained.

Here’s an example of the disk space outputs you might see:

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You may find directories still consuming space that relate to Kubernetes’ operational needs, including storage for secrets and temporary files created during runtime.

Analyzing What is Retaining Disk Space

1. Data That Must Be Retained

Kubernetes requires certain data to be maintained for operational purposes even when pods are deleted:

Default service token: This token is often retained for security and operational reasons within the cluster.

Other temporary files: Kubernetes may create other temporary files and directories that are necessary while the cluster is operational.

2. Stopping the Cluster

To fully release the disk space, you may actually need to stop the Kubernetes cluster rather than merely deleting pods or deployments. The command systemctl stop k3s will effectively bring down your k3s cluster and should allow the system to clear out the relevant disk usage. This step is essential if you want to ensure that all related processes are terminated, allowing the system to free up the held disk space effectively.

Clearing Disk Space Steps

Now that we understand the underlying reasons for retained disk usage, here’s a structured approach to resolve the situation:

Step 1: Delete Deployments and Pods

Start by cleaning up all running deployments and pods with the following commands:

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Step 2: Stopping the Kubernetes Cluster

After confirming that no deployments or pods remain, stop the k3s cluster:

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Step 3: Check Disk Usage

Once the cluster has stopped, check the disk usage again to see if the space is released:

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Step 4: Troubleshoot Further

If you still see high disk usage, consider checking the following:

Use ctr containers ls to check for remaining containers that may not have been cleaned up.

Investigate /var/lib/kubelet for any lingering files from previous pods.

Conclusion

Administering disk space within a Kubernetes environment can be tricky, especially for those new to the platform. The issue typically stems from misunderstanding how Kubernetes manages necessary operational data. By stopping the cluster and conducting a thorough cleanup, you ensure that your disk space is effectively managed and doesn't retain unnecessary data that could impact performance.

If you follow the steps outlined in this guide, you should successfully manage your Kubernetes file system and regain that precious disk space!