This implements a [hosts] <=> [images] mapping in the simple scheduler
that partitions your host resources into the part that services a
particular image set, and the general cloud. This is useful, for
example, if you want to specify a set of hosts to run utility VMs
(cloudpipe, bastion, etc) that you don't want consuming resources from
your generally available pool.
When specifying a host with --isolated_hosts flags (comma-separated
list) those hosts will only run the images specified in
--isolated_images, and will not run any other images. The isolated
images will not run on any other hosts.
You can specify --skip_isolated_core_check to allow overcommitting of
the isolated hosts. This allows utility vms that are not cpu bound to
avoid the resource cheks the scheduler usually performs (based off of
--max_cores).
Change-Id: Ib2db5a605cb7560a169af9ff2a6dadb649da9c1d
952de1af0b