What is Eventarc in GCP?

Eventarc is GCP's event routing service that triggers Google Cloud services based on events from GCP services, custom applications, or external sources via Cloud Audit Logs. It provides a standardized, consistent eventing experience using CloudEvents (CNCF standard). Eventarc routes events to: Cloud Run, Cloud Functions (2nd gen), GKE, and Workflows. Event sources: Cloud Audit Logs (every API call becomes an event — create a VM, upload to Storage, etc.), Cloud Pub/Sub, third-party sources. Example trigger: "When a file is created in Cloud Storage (via audit log), route the event to a Cloud Run service." Eventarc replaces the various service-specific trigger mechanisms with a unified system. It is foundational to Google's event-driven architecture vision alongside Pub/Sub and Cloud Tasks.