You can configure multiple node for a standalone Engine to serve as a backup of the
primary node.
Backup Engine instances do not accept requests from clients. They act as passive
failover servers.
When the primary Engine node fails, one of the back up Engine nodes takes over as
the primary. When the failed Engine server is restarted, it joins the pool of backup
Engines. Each backup Engine server communicates with the primary Engine server to see
if it is still running. This communication occurs every 5 seconds
A backup Engine takes over as primary when all of the following conditions are
true:
- The primary Engine does not accept or does not respond to the request from the
backup Engine. The backup Engine assumes the primary is not running.
- The primary Engine host is reachable. Network failures between nodes do
not trigger a backup takeover.