High Availability and Failover

High Availability and Failover

1. High Availability and Failover

The former 2019 MariaDB/CentOS design essay is obsolete. Detailed production topology and failover runbooks must remain restricted.

1.1. Current architectural entry points

  • modules/ProvHA — HA-specific commands, observers, and slave configuration rebuilds

  • database/migrations/BaseMigration.php — database/system scope and HA-aware behavior

  • app/Console/Kernel.php — module-aware scheduling

  • queue worker and service configuration under Install/files/

1.2. Public-safe principles

  • Separate stateless application processes from stateful databases/services

  • Make config rebuild and synchronization commands idempotent

  • Use read-only or role-specific connections where required

  • Prevent overlapping scheduled rebuilds

  • Test failover in an approved non-production environment

Exact node roles, addresses, credentials, and recovery procedures belong in restricted maintainer documentation.