Move nova host discovery to a new controller_post step

Currently, host discovery is executed from the compute nodes after each
compute setup. This will be a problem in future as it requires db access
and credentials in nova config file in the compute nodes which is not
recommended and will be forbiden in future [1].

This patch is removing it from the compute.pp template and moving it to
a new step controller_post that will be executed in the controller after
executing the rest of puppet manifests.

[1] http://lists.openstack.org/pipermail/openstack-discuss/2020-November/018875.html

Change-Id: I3ed2780b55ff6944aa7bf40f259f9c4e03389373

packstack/plugins/puppet_950.py

@@ -265,6 +265,10 @@ def prepare_puppet_modules(config, messages):
         manifestfile = "%s_compute.pp" % host
         appendManifestFile(manifestfile, manifestdata, marker='compute')
 
+    manifestdata = getManifestTemplate("controller_post")
+    manifestfile = "%s_controller_post.pp" % config['CONFIG_CONTROLLER_HOST']
+    appendManifestFile(manifestfile, manifestdata, marker='controller')
+
 
 def finalize(config, messages):
     for hostname in filtered_hosts(config):

packstack/puppet/modules/packstack/manifests/nova/compute.pp

@@ -94,10 +94,6 @@ class packstack::nova::compute ()
       passthrough => hiera('CONFIG_NOVA_PCI_PASSTHROUGH_WHITELIST')
     }
 
-    include ::nova::cell_v2::discover_hosts
-
-    Class['nova::compute'] ~> Class['nova::cell_v2::discover_hosts']
-
     # Tune the host with a virtual hosts profile
     ensure_packages(['tuned'], {'ensure' => 'present'})
 

packstack/puppet/templates/controller_post.pp

@@ -0,0 +1,14 @@
+stage { "init": before  => Stage["main"] }
+
+Exec { timeout => hiera('DEFAULT_EXEC_TIMEOUT') }
+Package { allow_virtual => true }
+
+class {'::packstack::prereqs':
+  stage => init,
+}
+
+include ::nova::cell_v2::discover_hosts
+
+notify {'Discovering compute nodes': } ~> Class['nova::cell_v2::discover_hosts']
+
+