Understanding Corosync Architecture in FreePBX High Availability
by Provider Adminlast verified 2026-08-13
Overview
Corosync provides the essential cluster membership and messaging infrastructure for FreePBX High Availability (HA) deployments. This guide covers how Corosync operates beneath Pacemaker to maintain quorum, manage node state, and prevent split-brain scenarios in voice environments. Readers will learn the core concepts, configuration mechanics, and monitoring commands needed to manage cluster messaging effectively.
Key takeaways
- Corosync provides low-level cluster membership, messaging, and health monitoring for FreePBX HA.
- Pacemaker relies on Corosync to manage high-level resources such as Asterisk, Floating IPs, and MariaDB.
- The Totem protocol guarantees ordered token passing and node state synchronization across cluster members.
- Dedicated network links for Corosync heartbeats prevent false-positive failovers caused by voice media congestion.
Prerequisites
- Basic knowledge of Linux system administration and cluster architecture.
- Familiarity with FreePBX HA active/passive configurations.
- Root access to a dual-node FreePBX environment via SSH.
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