Comment 0 for bug 1673600

https://github.com/openstack/instack-undercloud/blob/master/undercloud.conf.sample#L193

Exactly like it says in the comment if you attempt to build a >30 node Overcloud but forgot to tune this value your deploys will sit forever trying to schedule and then fail.

Since this tunable isn't documented anyone who just follows the documentation will run right into it if they have a large enough cloud.

Once you actually manage to find this line (it's not often referenced anywhere) you then have to redeploy your undercloud and then try again. Or take some other steps to circumvent the bug, a common feature in large deployments is to pin instances to specific bare metal nodes for ease of debugging hardware issues, that practice hides this issue.

I'm happy to contribute some lines to the docs about this, but is there any way we can somehow set this value to the size of the cloud your attempting to deploy so that the user doesn't have yet another mandatory configuration option?