component:
    set of resources
        -> resource needs to be able to determine current and desirable state


a resource:
    has properties
        -> describe the content on the system

        -> validation (zope.schema?)

    parameters
        -> influence how the resource works

    meta-parameters
        -> require, trigger, ...

    special property:
        ensure


provider:
    parse on-system status to 'is status' of resource and flush to system from
    'should be' status of resource



commands: 
    * update load balancer
    * update app servers
        -> restart app servers
    * restart app servers
    * 



batou remote:
    gather the current status of all resource from the remote nodes first,
    then figure out what to do, especially if interdependencies need to be
    managed
