Leader election.

also: leader elections · elect a leader · elected leader

Nodes agreeing that exactly one of them is the leader that does the work, and choosing a new one when it fails.

the two-minute refresher

Example: only one scheduler should fire the 2 a.m. billing job.
Usually built on a coordination service (etcd, ZooKeeper) using leases or consensus.
Hard part: a paused or partitioned leader may still think it leads.
So pair election with fencing tokens that let resources reject a stale leader.

also: leader elections · elect a leader · elected leader

Nodes agreeing that exactly one of them is the leader that does the work, and choosing a new one when it fails.

Example: only one scheduler should fire the 2 a.m. billing job.
Usually built on a coordination service (etcd, ZooKeeper) using leases or consensus.
Hard part: a paused or partitioned leader may still think it leads.
So pair election with fencing tokens that let resources reject a stale leader.