Pogo is a distributed supervisor for clustered Elixir applications.
It uses battle-tested distributed named process groups (:pg) under the hood to maintain cluster-wide state and coordinate work between local supervisors running on different nodes.
Features of distributed supervisor:
- automatically chooses a node to locally supervise child process
- a child process running in the cluster can be started or stopped using any local supervisor
- ensures a child is started only once in the cluster (as long as its child spec is unique)
- redistributes children when cluster topology changes
In that aspect it’s similar to Horde or Swarm, but doesn’t provide a distributed registry (Horde and Swarm do). Internals obviously are different - Horde uses ∂-CRDT, Swarm uses Interval Tree Clock for synchronization. Pogo’s local supervisors don’t exchange messages to synchronize state, but rely on Erlang’s process groups, observe their memberships and adjust their local state based on it.
For anyone interested, Pogo’s inner workings have been detailed in an introductory blog post 
.
To provide some context, the library was developed at Telnyx as an alternative to Horde as we couldn’t overcome some problems that TBH could have been peculiar to our environment (20+ node cluster with quite dynamic membership). Not that it went smoothly 
but since version 0.3 it’s been quite stable.
