Kube-state-metrics is a simple yet powerful service that acts as a bridge between the Kubernetes API server and monitoring systems like Prometheus. It listens to the Kubernetes API server, collects information about the state of various Kubernetes objects (pods, deployments, services, etc.), and exposes this information as metrics in a format that can be easily consumed by Prometheus or other compatible monitoring systems.
* Resource availability and utilization (CPU, memory, storage) * Deployment and pod status (running, pending, failed, etc.) * Resource labels and annotations * Object creation and deletion timestamps
While Kube-state-metrics primarily operates as a service within your Kubernetes cluster, here's an illustrative example of a Prometheus query that leverages Kube-state-metrics data:
``` sum(kube_pod_status_phase{phase=“Running”}) by (namespace) ```
This query calculates the number of running pods in each namespace, providing a quick overview of your application deployments.