Various post-upgrade fixes

The config file gets restored so the config cache needs refreshing.

Touch .guestagent.prepare.end file after upgrade to fix the problem of
the guestagent not knowing if prepare has ran.

Write the volume mount to fstab to persist after subsequent restarts.

Change-Id: I3831de12c999ef8818e80ecdb29f1d86ff8cd5c8
Closes-bug: #1645460
Depends-On: I5c1714b7839b2736c50f2daa2f4506c4006815a1

releasenotes/notes/post-upgrade-fixes-828811607826d433.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - After upgrading the guestagent was in an inconsistent state. This became
+    apparent after restarting or resizing the instance after upgrading.

trove/guestagent/datastore/experimental/postgresql/manager.py

@@ -159,7 +159,8 @@ class Manager(manager.Manager):
         self.app.stop_db()
         if 'device' in upgrade_info:
             self.mount_volume(context, mount_point=upgrade_info['mount_point'],
-                              device_path=upgrade_info['device'])
+                              device_path=upgrade_info['device'],
+                              write_to_fstab=True)
         self.app.restore_files_post_upgrade(upgrade_info)
         self.app.start_db()
 

trove/guestagent/datastore/experimental/postgresql/service.py

@@ -561,6 +561,8 @@ class PgSqlApp(object):
                                   force=True, as_root=True)
             operating_system.remove(upgrade_info['save_etc'], force=True,
                                     as_root=True)
+        self.configuration_manager.refresh_cache()
+        self.status.set_ready()
 
 
 class PgSqlAppStatus(service.BaseDbStatus):

trove/guestagent/datastore/mysql_common/manager.py

@@ -290,6 +290,7 @@ class MySqlManager(manager.Manager):
         operating_system.copy("%s/." % upgrade_info['home_save'],
                               os.path.expanduser('~'),
                               preserve=True, as_root=True)
+        self.configuration_manager.refresh_cache()
         app.start_mysql()
 
     def restart(self, context):

trove/guestagent/datastore/service.py

@@ -97,16 +97,19 @@ class BaseDbStatus(object):
         """Called before restarting DB server."""
         self.restart_mode = True
 
+    def set_ready(self):
+        prepare_end_file = guestagent_utils.build_file_path(
+            self.GUESTAGENT_DIR, self.PREPARE_END_FILENAME)
+        operating_system.write_file(prepare_end_file, '')
+        self.__refresh_prepare_completed()
+
     def end_install(self, error_occurred=False, post_processing=False):
         """Called after prepare has ended."""
 
         # Set the "we're done" flag if there's no error and
         # no post_processing is necessary
         if not (error_occurred or post_processing):
-            prepare_end_file = guestagent_utils.build_file_path(
-                self.GUESTAGENT_DIR, self.PREPARE_END_FILENAME)
-            operating_system.write_file(prepare_end_file, '')
-            self.__refresh_prepare_completed()
+            self.set_ready()
 
         final_status = None
         if error_occurred: