Performs a comprehensive health check of a CockroachDB cluster. Gathers deployment context first, then provides tier-appropriate diagnostics. Self-Hosted uses SQL against node-level system tables and CLI. Advanced/BYOC use Cloud Console and SQL with node visibility. Standard monitors provisioned compute and workload via Cloud Console. Basic monitors Request Unit consumption and connectivity. Use for daily checks, pre-maintenance validation, post-incident verification, or production readiness assessment.