ManageIQ worker creation and start

worker_creation

...
MiqServer.start
  ...
  server.start [1]
  ...
  server.monitor_loop [2]

[1] server.start
  deactivate/activate roles
  monitor_servers and roles
  sync active roles
  ...
  start_drb_server
  sync_workers [5]  (one time sync_workers)
  wait for workers
  "started"

[2] server.monitor_loop
  loop { monitor[3]; sleep }

[3] server.monitor
  heartbeat
  ...
  monitor_workers [4]
  ...

[4] server.monitor_workers
  ...
  sync_workers [5]
  check not responding/pending stop
  post messages for workers
  ...

[5] server.sync_workers
  self.class.monitor_class_names.each {|klass| klass.constantize.sync_workers[6] }
  #monitor_class_names is a harcoded constant list of all of the workers classes
  ...

[6] MiqWorker#sync_workers (for each worker class)
  ...
  MiqWorker.start_worker [7]

[7] MiqWorker.start_worker
  ...
  w = create_worker_record (basically .create)
  w.start [8]

[8] MiqWorker#start
  start_runner [9]

[9] MiqWorker#start_runner  (each worker class can specify how they want to start their runner, default is to fork)
  MiqWorker.before_fork
  pid = fork { MiqWorker.after_fork; MiqWorker::Runner.start_worker [10] }
  Process.detach(pid)

[10] MiqWorker::Runner.start_worker
  new.start [11]

[11] MiqWorker::Runner#start
  prepare [12]
  run [13]

[12] MiqWorker::Runner#prepare
  ...
  started_worker_record (sets row to 'started')
  ...
  do_before_work_loop

[13] MiqWorker::Runner#run / do_work_loop
  loop do
    hearbeat
    do_work
    ...
    sleep
  end