Refactor config drive mounting

There are a few places where we mount the config drive which
is not done in a consistent manner which results in failures
for the cases where the config drive is VFAT, which makes the
device label report as CONFIG-2 and not config-2 (uppercase).

This refactors the mounting and unmounting codebase to the
same block and reuses it to ensure a consistent behaviour across
tests, also letting the tags checks pass when using VFAT for
config drives.

Change-Id: I529cff87c848bc87d63d2ec407ed18cdd631ecef

releasenotes/notes/create-mount-config-drive-to-lib-1a6e912b8afbcc7e.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - A function has been added to the common library to allow mounting and
+    unmounting of the config drive consistently.

tempest/api/compute/servers/test_device_tagging.py

@@ -264,25 +264,13 @@ class DeviceTaggingTest(base.BaseV2ComputeTest):
 
         # Verify metadata on config drive
         if CONF.compute_feature_enabled.config_drive:
-            cmd_blkid = 'blkid -t LABEL=config-2 -o device'
             LOG.info('Attempting to verify tagged devices in server %s via '
                      'the config drive.', server['id'])
-            dev_name = self.ssh_client.exec_command(cmd_blkid)
-            dev_name = dev_name.rstrip()
-            try:
-                self.ssh_client.exec_command('sudo mount %s /mnt' % dev_name)
-            except exceptions.SSHExecCommandFailed:
-                # So the command failed, let's try to know why and print some
-                # useful information.
-                lsblk = self.ssh_client.exec_command('sudo lsblk --fs --ascii')
-                LOG.error("Mounting %s on /mnt failed. Right after the "
-                          "failure 'lsblk' in the guest reported:\n%s",
-                          dev_name, lsblk)
-                raise
-
+            self.ssh_client.mount_config_drive()
             cmd_md = 'sudo cat /mnt/openstack/latest/meta_data.json'
             md_json = self.ssh_client.exec_command(cmd_md)
             self.verify_device_metadata(md_json)
+            self.ssh_client.unmount_config_drive()
 
 
 class DeviceTaggingTestV2_42(DeviceTaggingTest):

tempest/lib/common/utils/linux/remote_client.py

@@ -11,6 +11,7 @@
 #    under the License.
 
 import functools
+import re
 import sys
 
 import netaddr
@@ -126,3 +127,27 @@ class RemoteClient(object):
             cmd = 'sudo {cmd} -I {nic}'.format(cmd=cmd, nic=nic)
         cmd += ' -c{0} -w{0} -s{1} {2}'.format(count, size, host)
         return self.exec_command(cmd)
+
+    def mount_config_drive(self):
+        """Mount the config drive inside a virtual machine
+
+        This method will not unmount the config drive, so unmount_config_drive
+        must be used for cleanup.
+        """
+        cmd_blkid = 'blkid | grep -i config-2'
+        result = self.exec_command(cmd_blkid)
+        dev_name = re.match('([^:]+)', result).group()
+
+        try:
+            self.exec_command('sudo mount %s /mnt' % dev_name)
+        except tempest.lib.exceptions.SSHExecCommandFailed:
+            # So the command failed, let's try to know why and print some
+            # useful information.
+            lsblk = self.exec_command('sudo lsblk --fs --ascii')
+            LOG.error("Mounting %s on /mnt failed. Right after the "
+                      "failure 'lsblk' in the guest reported:\n%s",
+                      dev_name, lsblk)
+            raise
+
+    def unmount_config_drive(self):
+        self.exec_command('sudo umount /mnt')

tempest/scenario/test_server_basic_ops.py

@@ -14,7 +14,6 @@
 #    under the License.
 
 import json
-import re
 
 from tempest.common import utils
 from tempest.common import waiters
@@ -94,22 +93,13 @@ class TestServerBasicOps(manager.ScenarioTest):
             result = self.servers_client.show_password(self.instance['id'])
             self.assertEqual(data, result['password'])
 
-    def _mount_config_drive(self):
-        cmd_blkid = 'blkid | grep -i config-2'
-        result = self.ssh_client.exec_command(cmd_blkid)
-        dev_name = re.match('([^:]+)', result).group()
-        self.ssh_client.exec_command('sudo mount %s /mnt' % dev_name)
-
-    def _unmount_config_drive(self):
-        self.ssh_client.exec_command('sudo umount /mnt')
-
     def verify_metadata_on_config_drive(self):
         if self.run_ssh and CONF.compute_feature_enabled.config_drive:
             # Verify metadata on config_drive
-            self._mount_config_drive()
+            self.ssh_client.mount_config_drive()
             cmd_md = 'sudo cat /mnt/openstack/latest/meta_data.json'
             result = self.ssh_client.exec_command(cmd_md)
-            self._unmount_config_drive()
+            self.ssh_client.unmount_config_drive()
             result = json.loads(result)
             self.assertIn('meta', result)
             msg = ('Failed while verifying metadata on config_drive on server.'
@@ -119,10 +109,10 @@ class TestServerBasicOps(manager.ScenarioTest):
     def verify_networkdata_on_config_drive(self):
         if self.run_ssh and CONF.compute_feature_enabled.config_drive:
             # Verify network data on config_drive
-            self._mount_config_drive()
+            self.ssh_client.mount_config_drive()
             cmd_md = 'sudo cat /mnt/openstack/latest/network_data.json'
             result = self.ssh_client.exec_command(cmd_md)
-            self._unmount_config_drive()
+            self.ssh_client.unmount_config_drive()
             result = json.loads(result)
             self.assertIn('services', result)
             self.assertIn('links', result)