This agent does a lot of things, therefore it is split into "roles". Each role defines which threads are to be run (usually these are for periodic tasks), which code gets run on startup, and so on.

Multiple roles can be loaded together in a single agent instance.

As the agent also acts on Resque jobs, the agent is split into two process types (the $mode):

• main
• worker

Both can be combined into a single process ($mode == both), but this is not recommended for production setups. It is expected that in production multiple worker processes will be used.

The main process exposes a Thrift server. The worker processes call

• if needed - into the main process (using the Thrift server). This is usually only necessary for the AppHost role, where the worker processes would need to modify Scheduler state.

For the Gateway role, the Thrift server is also used by the external SshGateway process/service. There's also an additional TCP interface for the HttpGateway service, this is implemented using EventMachine.

Copyright 2011, 2012 Efficient Cloud Ltd.

Released under the MIT license.