Description of problem:
If you've had your OverCloud nodes registered to a Red Hat Satellite (upstream CDN) and something bad happens which wipes out a node and you want to delete your stack and start over, heat will currently wait for RHELUnregistrationDeployment to time out, which by default is four hours.
A documented way of recovering would be nice.


Version-Release number of selected component (if applicable):
openstack-tripleo-heat-templates-0.8.6-121.el7ost.noarch

How reproducible:
Every time


Steps to Reproduce:
1. Deploy an overcloud, making sure your nodes are registered to a Satellite
2. Wipe out a node
3. heat stack-delete overcloud



Additional info:
A few suggestions for improving the situation:

1. heat stack-delete overcloud

2. heat resource-list -n5 overcloud | grep RHELUnregistrationDeployment

3. heat resource-signal <nested stack id> RHELUnregistrationDeployment

Where <nested stack id> is the stack name/id containing the
RHELUnregistrationDeployment resource (this is included in the
resource-list output as the last column in recent heat/heatclient versions,
alternatively it can be derived from the heat stack-list -n | grep
NodeExtraConfig output)

Note you'll repeat step (3) with a different nested stack ID, e.g once per
node, after which the delete should complete OK.

Another suggestion is to run

heat deployment-delete <id_of_RHELUnregistrationDeployment> 

Yet another way would be to implement an independent timeout for the Software Deployment resource, but that is an RFE for heat.
Another approach would be to tell heat not to expect any signal for
unregistration:

http://docs.openstack.org/developer/heat/template_guide/openstack.html#OS::Heat::SoftwareDeployment

e.g we could set the signal_transport == NO_SIGNAL (or make this easily
configurable) - the main disadvantage of doing this by default is you then
fail to catch any real unregistration failures when you're not recovering
from the nodes-aren't-there scenario under discussion here.