Add Kubernetes Metrics API support to utils module

[Copilot]

Adds native support for querying pod and node resource metrics (CPU/memory) from the metrics.k8s.io API, enabling monitoring and autoscaling workflows without external dependencies.

Changes

• New module kubernetes/utils/metrics.py with three functions:

  • get_nodes_metrics(api_client) - cluster-wide node metrics
  • get_pods_metrics(api_client, namespace, label_selector=None) - namespace-scoped pod metrics with optional label filtering
  • get_pods_metrics_in_all_namespaces(api_client, namespaces, label_selector=None) - multi-namespace aggregation with per-namespace error isolation

• Testing:

  • 8 unit tests in kubernetes/test/test_metrics.py covering success paths, validation, filtering, and error handling
  • End-to-end test in kubernetes/e2e_test/test_utils.py that validates metrics retrieval against a real cluster with metrics-server

• Documentation: API reference, usage patterns, and troubleshooting guide in kubernetes/docs/metrics.md

• Example: Working demonstration in examples/metrics_example.py

Usage

from kubernetes import client, config, utils

config.load_kube_config()
api = client.ApiClient()

# Node metrics
nodes = utils.get_nodes_metrics(api)
for node in nodes['items']:
    print(f"{node['metadata']['name']}: {node['usage']}")

# Pod metrics with label filtering
pods = utils.get_pods_metrics(api, 'production', 'app=nginx')
for pod in pods['items']:
    for container in pod['containers']:
        print(f"{container['name']}: {container['usage']}")

# Multi-namespace with error handling
results = utils.get_pods_metrics_in_all_namespaces(
    api, ['default', 'kube-system']
)

Requirements

Requires metrics-server installed in target cluster. Uses existing CustomObjectsApi to access metrics.k8s.io/v1beta1 endpoints.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[feat]: Integrate Kubernetes Metrics API into the Python Client</issue_title>
<issue_description>What is the feature and why do you need it:

The feature is the integration of the Kubernetes Metrics API into the Python client. This addition will allow users to retrieve metrics data directly through the client, enabling more streamlined monitoring and auto-scaling workflows. Currently, the client lacks native support for querying metrics data, making it necessary to rely on external tools or libraries.

Describe the solution you'd like to see:

I envision the addition of a new module or extension to the existing client specifically dedicated to handling metrics data retrieval. This module should include methods for querying various types of metrics, such as pod metrics, node metrics, and custom metrics. It should also be designed to seamlessly integrate with the existing client structure, providing a consistent user experience.

The solution should ensure compatibility with different versions of Kubernetes to support users on various clusters. Additionally, comprehensive documentation and examples should be provided to guide users in effectively utilizing the new metrics functionalities.

Overall, the goal is to empower users with the ability to access and utilize metrics data directly through the Python client, eliminating the need for external dependencies and enhancing the client's capabilities in monitoring and scaling applications.

</issue_description>

<agent_instructions>Please implement support for easy access to pod and node metrics, you can look at similar code in Java here: https://github.com/kubernetes-client/java/blob/master/util/src/main/java/io/kubernetes/client/Metrics.java
</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@roycaihw /help

@Parvezkhan0 Could you elaborate what Kubernetes Metrics API is?</comment_new>
<comment_new>@k8s-ci-robot
@roycaihw:
This request has been marked as needing help from a contributor.

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In response to this:

/help

@Parvezkhan0 Could you elaborate what Kubernetes Metrics API is?

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

• Fixes [feat]: Integrate Kubernetes Metrics API into the Python Client #2135

---

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[brendandburns]

@copilot please add an end to end test also.

[Copilot]

@copilot please add an end to end test also.

Added e2e test in commit c234b6c. The test validates all three metrics functions (node metrics, pod metrics with label filtering, and multi-namespace aggregation) against a real cluster. It gracefully skips if metrics-server is not available.