37. Triggering an Election
• 하나의 노드에서 Primary 가 연결이 안
될때.(단 해당노드는 Arbiter가 아니어
야 함. Heartbeat(timeout:20))
• 해당 노드의 priority 가 다른 노드보다
크거나 같을 경우.
38. Picking Primary
1. get maxLocalOpOrdinal from each server.
2. if a majority of servers are not up (from this
server's POV), remain in Secondary mode and
stop.
3. if the last op time seems very old, stop and
await human intervention.
4. else, using a consensus protocol, pick the server
with the highest maxLocalOpOrdinal as the
Primary.