Node ID

Each Stalwart instance in a cluster must be assigned a unique identifier to distinguish it from other nodes. This identifier is configured using the cluster.node-id setting and must be a positive integer. It plays a critical role in coordination, logging, and internal message routing, allowing each node to be uniquely addressed within the cluster.

The node ID must be unique across the entire cluster—no two nodes should share the same ID. Assigning duplicate IDs can lead to unpredictable behavior, coordination conflicts, and data inconsistencies.

For example:

[cluster]
node-id = 1

In this example, the current node is assigned the ID 1. You would assign different values (e.g., 2, 3, 4, etc.) to other nodes in the cluster, ensuring no overlap.

Care should be taken to maintain a consistent and documented mapping of node IDs, especially in larger clusters or automated deployment environments.