Comment 7 for bug 1053754

The force_hosts scheduler hint has been replaced by specifying an availability zone.

See the following post over on the Ubuntu launchpad: https://bugs.launchpad.net/ubuntu/+source/nova/+bug/1061665/comments/5

i.e. To deploy instance 'test1' to host 'nova-compute-1' in availability zone 'nova':
nova boot --flavor 1 --image {some-image-uuid} --availability-zone nova:nova-compute-1 test1

I'm not exactly sure what the intended replacement is for ignore_hosts but I'd expect that you should just use the FilterScheduler filters to separate your instances according to your requirements:
http://docs.openstack.org/trunk/openstack-compute/admin/content/scheduler-filters.html

It looks like the other bug has been triaged to update documentation, but otherwise the following documentation needs to be updated:
http://docs.openstack.org/trunk/openstack-compute/admin/content/specify-host-to-boot-instances-on.html