Google Cloud Monitoring vs Prometheus

Google Cloud Monitoring provides visibility into the performance, availability, and health of applications and infrastructure. It automatically collects metrics for Google Cloud services and also supports hybrid and multicloud environments. The service brings together metrics, uptime checks, dashboards, and alerts; users can build custom dashboards and multi-condition alert policies. Service-level objectives can be inferred automatically or defined by users, with alerts for violations. Script-based synthetic monitors test web applications and APIs. For Kubernetes, Managed Service for Prometheus handles managed or self-deployed metric collection. On supported Linux and Windows virtual machines, the Ops Agent collects logs and metrics and includes third-party application integrations. Alerts can be sent through email, Slack, PagerDuty, Pub/Sub, SMS, webhooks, or the Cloud Mobile App. Cloud Monitoring API v3 offers programmatic access to metrics scopes, dashboards, and alerting policies. It runs in the cloud and lists API, Linux, web, and Windows platforms. Pricing is usage-based, with free monthly allotments on several meters; charges can depend on ingested data, time series returned, and check executions.

Prometheus is a free, open-source toolkit for systems monitoring and alerting that collects metrics as time series. Each series is identified by a metric name and key-value labels, and PromQL is used to query the data. Prometheus typically gathers metrics by pulling over HTTP; it can also receive pushed data through an intermediary gateway. Targets can be found with service discovery or configured statically. The main server runs as a standalone monolithic binary without external dependencies, and official components are available as precompiled binaries and Docker images. Its ecosystem includes client libraries, exporters, Pushgateway and Alertmanager, with Grafana for visualization and webhooks for alert notifications. Prometheus and most exporters support TLS, client certificate authentication and HTTP Basic Authentication. The project advises against exposing component HTTP endpoints to public networks without protective measures. Servers do not depend on network storage or remote services, which the project says can help during outages. Prometheus is not recommended for uses requiring 100% accurate data, such as per-request billing.