API Server Client Details Test

The API Server (also known as kube-apiserver) is a critical component that runs on the master node. It serves as the entry point for all API requests to the Kubernetes cluster. The API server exposes the Kubernetes API, which is the interface that allows users and components to interact with the cluster. Ant any given time a number of client may be connected to API Server to retrive or modify the resources in the cluster.

Monitoring API Server clients for connectivity is essential to ensure that all clients are able to connect to the cluster and able to retrieve the resources. It is essential to ensure the stability, performance, and security of the cluster.

This test monitors the API Server clients and reveals key metrics related to client certificates which are crucial to ensuring uninterrupted connectivity to the server. By analyzing the metrics the administrators can ensure that clients are able to connect to the server and take preemptive actions if any certificate is about to expire.

Target of the test : A Kubernetes Master Node

Agent deploying the test : A remote agent

Outputs of the test : One set of results for target Kubernetes Master node being monitored.

Configurable parameters for the test
Parameter	Description
Test Period	How often should the test be executed.
Host	The IP address of the host for which this test is to be configured.
Port	Specify the port at which the specified Host listens. By default, this is 6443.
Timeout	Specify the duration (in seconds) beyond which the test will timeout in the Timeout text box. The default value is 10 seconds.
Metric URL	Each of the Kubernetes system components expose monitoring metrics through /metrics endpoint of the HTTP server. For components that don't expose endpoint by default, refer official Kubernetes distribution documentation site. Specify the metric URL textbox.

Measurements made by the test
Measurement	Description	Measurement Unit
Client certificate expiration	Indicates the total number of client certificates which need to be monitored for expiration.	Number
Total client certificate expiration	Indicates the total number of days for which certificates are valid across all certificates.	Days
Average client certificate expiration	Indicates the average of available validity per certificate across all certificates.	Days