Multiple NK nodes coordinated — auto-sync site files / DB / certs / configs for geo CDN or HA. Business+.
Model
- Sync group (el_sync_group) — coordinated nodes
- Member node (el_sync_node) — role (master/slave), admin URL + SSH creds
- Sync object (el_sync_object) — which resources to sync
SSL auto-sync
Cron renewal success → push to sync-group nodes (initial issue + renewal). All nodes get new cert + reload within 5 min.
vs DB replication
Sync group is app-layer resource mirroring (sites/proxy/certs); DB replication is database engine layer. See DB Replication.