Description of configuration options for upgrade_levels

Configuration option = Default value	Description
[cells]
scheduler = nova.cells.scheduler.CellsScheduler	(StrOpt) Cells scheduler to use
[upgrade_levels]
cells = None	(StrOpt) Set a version cap for messages sent to local cells services
cert = None	(StrOpt) Set a version cap for messages sent to cert services
compute = None	(StrOpt) Set a version cap for messages sent to compute services
conductor = None	(StrOpt) Set a version cap for messages sent to conductor services
console = None	(StrOpt) Set a version cap for messages sent to console services
consoleauth = None	(StrOpt) Set a version cap for messages sent to consoleauth services
intercell = None	(StrOpt) Set a version cap for messages sent between cells services
network = None	(StrOpt) Set a version cap for messages sent to network services
scheduler = None	(StrOpt) Set a version cap for messages sent to scheduler services