Skip test_z99_crash_controller_non_main_vip unless kexec-tools available

In later OSP releases, kexec-tools package is not installed on overcloud
images - Due to this, controller nodes are not recovered after
a triggering a kernel panic on more then one (in a setup with
three controllers, two of them need to be healthy in order to have quorum)

Change-Id: I32a8cb7d803eefa89695bdde0b04cb22180dde66

tobiko/tests/faults/ha/test_cloud_recovery.py

@@ -173,6 +173,7 @@ class DisruptTripleoNodesTest(testtools.TestCase):
         cloud_disruptions.crash_controller_main_vip()
         OvercloudHealthCheck.run_after()
 
+    @overcloud.skip_unless_kexec_tools_installed
     def test_z99_crash_controller_non_main_vip(self):
         OvercloudHealthCheck.run_before()
         cloud_disruptions.crash_controllers_non_main_vip()

tobiko/tripleo/_overcloud.py

@@ -341,6 +341,21 @@ skip_unless_ovn_using_ha = tobiko.skip_unless(
     'OVN does not use HA DB model', is_ovn_using_ha)
 
 
+@functools.lru_cache()
+def are_kexec_tools_installed():
+    for controller in topology.list_openstack_nodes(group='controller'):
+        try:
+            sh.execute('rpm -q kexec-tools', ssh_client=controller.ssh_client)
+        except sh.ShellCommandFailed:
+            return False
+    return True
+
+
+skip_unless_kexec_tools_installed = tobiko.skip_unless(
+    'kexec-tools package not installed on controller nodes',
+    are_kexec_tools_installed)
+
+
 def overcloud_version() -> tobiko.Version:
     from tobiko.tripleo import _topology
     node = topology.find_openstack_node(group='overcloud')