Skip udev rule install in containers

Ensure that udev rules are not installed and reloaded
when running in a container; this is not permitted and
the udev rules are used for block devices, which are
not supported within container based deployments.

Change-Id: I9a580172fcbbf8cec63af7adccb0808915184658
Closes-Bug: 1776713

hooks/ceph_hooks.py

@@ -55,6 +55,7 @@ from charmhelpers.core.host import (
     add_to_updatedb_prunepath,
     restart_on_change,
     write_file,
+    is_container,
 )
 from charmhelpers.fetch import (
     add_source,
@@ -225,6 +226,10 @@ def install_udev_rules():
     Install and reload udev rules for ceph-volume LV
     permissions
     """
+    if is_container():
+        log('Skipping udev rule installation '
+            'as unit is in a container', level=DEBUG)
+        return
     for x in glob.glob('files/udev/*'):
         shutil.copy(x, '/lib/udev/rules.d')
     subprocess.check_call(['udevadm', 'control',

unit_tests/test_ceph_hooks.py

@@ -471,9 +471,11 @@ class CephHooksTestCase(unittest.TestCase):
         config.assert_called_with('availability_zone')
         environ.get.assert_called_with('JUJU_AVAILABILITY_ZONE')
 
+    @patch.object(ceph_hooks, 'is_container')
     @patch.object(ceph_hooks, 'subprocess')
     @patch.object(ceph_hooks, 'shutil')
-    def test_install_udev_rules(self, shutil, subprocess):
+    def test_install_udev_rules(self, shutil, subprocess, is_container):
+        is_container.return_value = False
         ceph_hooks.install_udev_rules()
         shutil.copy.assert_called_once_with(
             'files/udev/95-charm-ceph-osd.rules',
@@ -483,6 +485,16 @@ class CephHooksTestCase(unittest.TestCase):
             ['udevadm', 'control', '--reload-rules']
         )
 
+    @patch.object(ceph_hooks, 'is_container')
+    @patch.object(ceph_hooks, 'subprocess')
+    @patch.object(ceph_hooks, 'shutil')
+    def test_install_udev_rules_container(self, shutil, subprocess,
+                                          is_container):
+        is_container.return_value = True
+        ceph_hooks.install_udev_rules()
+        shutil.copy.assert_not_called()
+        subprocess.check_call.assert_not_called()
+
     @patch.object(ceph_hooks, 'config')
     @patch.object(ceph_hooks, 'cmp_pkgrevno')
     def test_use_short_objects(self, mock_cmp_pkgrevno, mock_config):