1. A content delivery (CD) system comprising a plurality of devices, each particular device of said plurality of devices comprising hardware including memory and at least one processor, and each said particular device being configured to run at least one CD service of a plurality of CD services, each CD service of said plurality of CD services having a corresponding type of CD service selected from a plurality of CD service types; and wherein at least some CD services of said plurality of CD services: (i) produce event output relating to respective operation of said at least some CD services of said plurality of CD services, wherein at least some of said event output from said at least some CD services of said plurality of CD services is provided to at least some of said plurality of CD services as event input, (ii) obtain event input from certain one or more CD services of said plurality of CD services, (iii) produce, as respective state output of said at least some of said CD services of said plurality of CD services, state information, said state information being based on event input from multiple CD services on multiple devices in said CD system, (iv) maintain configuration information specifying a first set of CD services that should be run on a devices, (v) obtain state information from said first set of CD services of said plurality of CD services, said first set of CD services running on at least two devices, and (vi) modify said configuration information to produce modified configuration information based at least on said state information obtained in (v), said modified configuration information specifying a second set of CD services, wherein said second set of CD services comprises a first at least some CD services of at least one different type than any service in said first set of CD services, and (vii) cause one or more devices of said plurality of devices to start at least one or more CD services of said first at least some CD services in accordance with said modified configuration information, wherein said at least one or more CD services started in (vii) include at least one CD service of said at least one different type.