workflow controller: leader election?

[static-moonlight]

I'm a little confused.

1. There are env variables, implying leader-election mechanics for Argo's workflow controller, and therefore implying horizontal scalability:
   • LEADER_ELECTION_IDENTITY
   • LEADER_ELECTION_DISABLE
   • LEADER_ELECTION_LEASE_DURATION
   • LEADER_ELECTION_RENEW_DEADLINE
   • LEADER_ELECTION_RETRY_PERIOD
2. The documentation clearly states:

   You cannot horizontally scale the controller.

Can someone please explain what these env variables are actually good for when (according to the documentation) horizontal scaling is not a thing for the workflow controller?

[tczhao]

You cannot horizontally scale the controller.

we can deploy multiple replicas of a controller simultaneously

LEADER_ELECTION

but only 1 of them is working at a time.

This mainly helps to reduce the time taken to resume service when 1 controller is down

[static-moonlight]

I see ... the time-to-recovery is so small though that I don't really see the point in this. Thank you for the answer.