It&#x27;s really not documented well (and the generated docs are a joke) but from what I can gather, it&#x27;s bog-standard PG replication with a go app to monitor the replication and do automated failover.<p>The monitor node appears to be there to act as neutral witness node so that a secondary is only promoted leader if it can reach the monitor <i>and</i> the monitor cannot reach the current leader. Hopefully, the leader also commits suicide when it cannot reach the monitor.<p>MS SQL server implements this pattern and calls it &quot;Database Mirroring Witness&quot;: <a href="https:&#x2F;&#x2F;msdn.microsoft.com&#x2F;en-us&#x2F;library&#x2F;ms175191.aspx" rel="nofollow">https:&#x2F;&#x2F;msdn.microsoft.com&#x2F;en-us&#x2F;library&#x2F;ms175191.aspx</a>