Series Upgrade

Implement the series-upgrade feature allowing to move between Ubuntu
series.

Change-Id: Iea24af291b3d9d5b7771f35c2374e8d7e9b655c3

hooks/charmhelpers/contrib/openstack/utils.py

@@ -186,7 +186,7 @@ SWIFT_CODENAMES = OrderedDict([
     ('queens',
         ['2.16.0', '2.17.0']),
     ('rocky',
-        ['2.18.0']),
+        ['2.18.0', '2.19.0']),
 ])
 
 # >= Liberty version->codename mapping
@@ -831,12 +831,25 @@ def _ows_check_if_paused(services=None, ports=None):
     """Check if the unit is supposed to be paused, and if so check that the
     services/ports (if passed) are actually stopped/not being listened to.
 
-    if the unit isn't supposed to be paused, just return None, None
+    If the unit isn't supposed to be paused, just return None, None
+
+    If the unit is performing a series upgrade, return a message indicating
+    this.
 
     @param services: OPTIONAL services spec or list of service names.
     @param ports: OPTIONAL list of port numbers.
     @returns state, message or None, None
     """
+    if is_unit_upgrading_set():
+        state, message = check_actually_paused(services=services,
+                                               ports=ports)
+        if state is None:
+            # we're paused okay, so set maintenance and return
+            state = "blocked"
+            message = ("Ready for do-release-upgrade and reboot. "
+                       "Set complete when finished.")
+        return state, message
+
     if is_unit_paused_set():
         state, message = check_actually_paused(services=services,
                                                ports=ports)
@@ -1339,7 +1352,7 @@ def pause_unit(assess_status_func, services=None, ports=None,
         message = assess_status_func()
         if message:
             messages.append(message)
-    if messages:
+    if messages and not is_unit_upgrading_set():
         raise Exception("Couldn't pause: {}".format("; ".join(messages)))
 
 
@@ -1689,3 +1702,52 @@ def install_os_snaps(snaps, refresh=False):
             snap_install(snap,
                          _ensure_flag(snaps[snap]['channel']),
                          _ensure_flag(snaps[snap]['mode']))
+
+
+def set_unit_upgrading():
+    """Set the unit to a upgrading state in the local kv() store.
+    """
+    with unitdata.HookData()() as t:
+        kv = t[0]
+        kv.set('unit-upgrading', True)
+
+
+def clear_unit_upgrading():
+    """Clear the unit from a upgrading state in the local kv() store
+    """
+    with unitdata.HookData()() as t:
+        kv = t[0]
+        kv.set('unit-upgrading', False)
+
+
+def is_unit_upgrading_set():
+    """Return the state of the kv().get('unit-upgrading').
+
+    To help with units that don't have HookData() (testing)
+    if it excepts, return False
+    """
+    try:
+        with unitdata.HookData()() as t:
+            kv = t[0]
+            # transform something truth-y into a Boolean.
+            return not(not(kv.get('unit-upgrading')))
+    except Exception:
+        return False
+
+
+def series_upgrade_prepare(pause_unit_helper=None, configs=None):
+    """ Run common series upgrade prepare tasks."""
+    set_unit_upgrading()
+    if pause_unit_helper and configs:
+        if not is_unit_paused_set():
+            pause_unit_helper(configs)
+
+
+def series_upgrade_complete(resume_unit_helper=None, configs=None):
+    """ Run common series upgrade complete tasks."""
+    clear_unit_paused()
+    clear_unit_upgrading()
+    if configs:
+        configs.write_all()
+        if resume_unit_helper:
+            resume_unit_helper(configs)

hooks/cinder_hooks.py

@@ -44,6 +44,8 @@ from cinder_utils import (
     filesystem_mounted,
     assess_status,
     scrub_old_style_ceph,
+    pause_unit_helper,
+    resume_unit_helper,
 )
 
 from cinder_contexts import ceph_config_file
@@ -85,6 +87,8 @@ from charmhelpers.contrib.openstack.utils import (
     is_unit_paused_set,
     pausable_restart_on_change as restart_on_change,
     CompareOpenStackReleases,
+    series_upgrade_prepare,
+    series_upgrade_complete,
 )
 
 from charmhelpers.contrib.storage.linux.ceph import (
@@ -154,6 +158,12 @@ def install():
 @restart_on_change(restart_map(), stopstart=True)
 @harden()
 def config_changed():
+    # if we are paused, delay doing any config changed hooks.
+    # It is forced on the resume.
+    if is_unit_paused_set():
+        log("Unit is pause or upgrading. Skipping config_changed", "WARN")
+        return
+
     conf = config()
 
     if conf['prefer-ipv6']:
@@ -633,6 +643,20 @@ def certs_changed(relation_id=None, unit=None):
     configure_https()
 
 
+@hooks.hook('pre-series-upgrade')
+def pre_series_upgrade():
+    log("Running prepare series upgrade hook", "INFO")
+    series_upgrade_prepare(
+        pause_unit_helper, CONFIGS)
+
+
+@hooks.hook('post-series-upgrade')
+def post_series_upgrade():
+    log("Running complete series upgrade hook", "INFO")
+    series_upgrade_complete(
+        resume_unit_helper, CONFIGS)
+
+
 if __name__ == '__main__':
     try:
         hooks.execute(sys.argv)

hooks/post-series-upgrade

@@ -0,0 +1 @@
+cinder_hooks.py

hooks/pre-series-upgrade

@@ -0,0 +1 @@
+cinder_hooks.py