docs: Architecture diagram to describe how the core modules interact

[cobolbaby]

Function call of job execution

[cobolbaby]

I'm curious about how dkron ensures that the Serf leader and Raft leader are on the same node. When the Raft cluster switches leaders, dkron reconciles the Serf members, doesn't it? @vcastellm

[vcastellm]

First of all, thanks for your contribution, the diagram is correct, I'll try to make it a bit more good looking and include it in documentation.

I'm curious about how dkron ensures that the Serf leader and Raft leader are on the same node. When the Raft cluster switches leaders, dkron reconciles the Serf members, doesn't it? @vcastellm

Serf it's a clustering/gossip messaging system, it doesn't have the concept of leader, when Raft switches leaders reconcile of members happens on Serf https://github.com/distribworks/dkron/blob/master/dkron/leader.go#L183 as you mention.