The Prometheus Operator is a Kubernetes monitoring orchestrator and controller that manages Prometheus clusters and observability components through declarative custom resources. It functions as a custom resource controller that translates high-level Kubernetes resource definitions into the configuration files required by the underlying monitoring software.
The project automates the deployment, scaling, and lifecycle of an observability stack, including the integration of components like Thanos and Alertmanager. It distinguishes itself by syncing monitoring targets, alerting rules, and scrape configurations directly via the Kubernetes API to maintain a consistent desired state across the cluster.
The system covers several capability areas, including automated target discovery via label queries, declarative alerting and recording rule management, and the configuration of remote storage endpoints. It also handles infrastructure state management, synthetic endpoint probing, and the synchronization of notification routing and receivers.
Resource correctness is maintained through admission webhooks that validate configuration rules and resource schemes before they are persisted to the cluster.
