Kubernetes API - Get Pods on Specific Nodes

Introduction

Retrieving Pods running on specific nodes in a Kubernetes cluster can be useful for debugging and resource management. In this guide, you'll learn how to use the Kubernetes API to filter Pods by node.

Prerequisites

Before proceeding, make sure:

• You have kubectl installed and configured.
• You have access to the Kubernetes API.

Using the Kubernetes API

List Pods with Node Information

To list Pods along with their node information, use:

kubectl get pods -o wide

This command displays additional details, including the node where each Pod is running.

Filter Pods by Node

To filter Pods running on a specific node, use:

kubectl get pods --field-selector spec.nodeName=<node-name>

Replace <node-name> with the name of the node you want to filter by.

Example

Suppose you want to retrieve Pods running on a node named worker-node-1. Run the following command:

kubectl get pods --field-selector spec.nodeName=worker-node-1

This lists all Pods running on worker-node-1.

Using the Kubernetes API Directly

You can also use the Kubernetes API directly to query Pods by node. Here's an example using curl:

curl -k -H "Authorization: Bearer <token>" \
https://<api-server>/api/v1/pods?fieldSelector=spec.nodeName=<node-name>

Replace <token> with your API token, <api-server> with the API server URL, and <node-name> with the node name.

Best Practices

• Use Labels: Label nodes and Pods for easier filtering.
• Monitor Resources: Use tools like kubectl top to monitor resource usage on nodes.
• Automate Queries: Use scripts or tools like kubectl plugins for frequent queries.

Conclusion

Using the Kubernetes API to retrieve Pods on specific nodes is a powerful way to manage and debug your cluster. By following these steps, you can efficiently filter and monitor Pods.