diff --git a/charmhelpers/contrib/openstack/utils.py b/charmhelpers/contrib/openstack/utils.py
index e719426..6184abd 100644
--- a/charmhelpers/contrib/openstack/utils.py
+++ b/charmhelpers/contrib/openstack/utils.py
@@ -306,7 +306,7 @@ def get_os_codename_install_source(src):
 
     if src.startswith('cloud:'):
         ca_rel = src.split(':')[1]
-        ca_rel = ca_rel.split('%s-' % ubuntu_rel)[1].split('/')[0]
+        ca_rel = ca_rel.split('-')[1].split('/')[0]
         return ca_rel
 
     # Best guess match based on deb string provided
diff --git a/charmhelpers/contrib/storage/linux/ceph.py b/charmhelpers/contrib/storage/linux/ceph.py
index e13e60a..7682820 100644
--- a/charmhelpers/contrib/storage/linux/ceph.py
+++ b/charmhelpers/contrib/storage/linux/ceph.py
@@ -291,7 +291,7 @@ class Pool(object):
 
 class ReplicatedPool(Pool):
     def __init__(self, service, name, pg_num=None, replicas=2,
-                 percent_data=10.0):
+                 percent_data=10.0, app_name=None):
         super(ReplicatedPool, self).__init__(service=service, name=name)
         self.replicas = replicas
         if pg_num:
@@ -301,6 +301,10 @@ class ReplicatedPool(Pool):
             self.pg_num = min(pg_num, max_pgs)
         else:
             self.pg_num = self.get_pgs(self.replicas, percent_data)
+        if app_name:
+            self.app_name = app_name
+        else:
+            self.app_name = 'unknown'
 
     def create(self):
         if not pool_exists(self.service, self.name):
@@ -313,6 +317,12 @@ class ReplicatedPool(Pool):
                 update_pool(client=self.service,
                             pool=self.name,
                             settings={'size': str(self.replicas)})
+                try:
+                    set_app_name_for_pool(client=self.service,
+                                          pool=self.name,
+                                          name=self.app_name)
+                except CalledProcessError:
+                    log('Could not set app name for pool {}'.format(self.name, level=WARNING))
             except CalledProcessError:
                 raise
 
@@ -320,10 +330,14 @@ class ReplicatedPool(Pool):
 # Default jerasure erasure coded pool
 class ErasurePool(Pool):
     def __init__(self, service, name, erasure_code_profile="default",
-                 percent_data=10.0):
+                 percent_data=10.0, app_name=None):
         super(ErasurePool, self).__init__(service=service, name=name)
         self.erasure_code_profile = erasure_code_profile
         self.percent_data = percent_data
+        if app_name:
+            self.app_name = app_name
+        else:
+            self.app_name = 'unknown'
 
     def create(self):
         if not pool_exists(self.service, self.name):
@@ -355,6 +369,12 @@ class ErasurePool(Pool):
                    'erasure', self.erasure_code_profile]
             try:
                 check_call(cmd)
+                try:
+                    set_app_name_for_pool(client=self.service,
+                                          pool=self.name,
+                                          name=self.app_name)
+                except CalledProcessError:
+                    log('Could not set app name for pool {}'.format(self.name, level=WARNING))
             except CalledProcessError:
                 raise
 
@@ -778,6 +798,25 @@ def update_pool(client, pool, settings):
     check_call(cmd)
 
 
+def set_app_name_for_pool(client, pool, name):
+    """
+    Calls `osd pool application enable` for the specified pool name
+
+    :param client: Name of the ceph client to use
+    :type client: str
+    :param pool: Pool to set app name for
+    :type pool: str
+    :param name: app name for the specified pool
+    :type name: str
+
+    :raises: CalledProcessError if ceph call fails
+    """
+    if ceph_version() >= '12.0.0':
+        cmd = ['ceph', '--id', client, 'osd', 'pool',
+               'application', 'enable', pool, name]
+        check_call(cmd)
+
+
 def create_pool(service, name, replicas=3, pg_num=None):
     """Create a new RADOS pool."""
     if pool_exists(service, name):
diff --git a/charmhelpers/contrib/storage/linux/utils.py b/charmhelpers/contrib/storage/linux/utils.py
index c942889..6f846b0 100644
--- a/charmhelpers/contrib/storage/linux/utils.py
+++ b/charmhelpers/contrib/storage/linux/utils.py
@@ -67,3 +67,19 @@ def is_device_mounted(device):
     except Exception:
         return False
     return bool(re.search(r'MOUNTPOINT=".+"', out))
+
+
+def mkfs_xfs(device, force=False):
+    """Format device with XFS filesystem.
+
+    By default this should fail if the device already has a filesystem on it.
+    :param device: Full path to device to format
+    :ptype device: tr
+    :param force: Force operation
+    :ptype: force: boolean"""
+    cmd = ['mkfs.xfs']
+    if force:
+        cmd.append("-f")
+
+    cmd += ['-i', 'size=1024', device]
+    check_call(cmd)
diff --git a/charmhelpers/core/hookenv.py b/charmhelpers/core/hookenv.py
index 89f1024..627d8f7 100644
--- a/charmhelpers/core/hookenv.py
+++ b/charmhelpers/core/hookenv.py
@@ -290,7 +290,7 @@ class Config(dict):
         self.implicit_save = True
         self._prev_dict = None
         self.path = os.path.join(charm_dir(), Config.CONFIG_FILE_NAME)
-        if os.path.exists(self.path):
+        if os.path.exists(self.path) and os.stat(self.path).st_size:
             self.load_previous()
         atexit(self._implicit_save)
 
@@ -310,7 +310,11 @@ class Config(dict):
         """
         self.path = path or self.path
         with open(self.path) as f:
-            self._prev_dict = json.load(f)
+            try:
+                self._prev_dict = json.load(f)
+            except ValueError as e:
+                log('Unable to parse previous config data - {}'.format(str(e)),
+                    level=ERROR)
         for k, v in copy.deepcopy(self._prev_dict).items():
             if k not in self:
                 self[k] = v
@@ -354,22 +358,40 @@ class Config(dict):
             self.save()
 
 
-@cached
+_cache_config = None
+
+
 def config(scope=None):
-    """Juju charm configuration"""
-    config_cmd_line = ['config-get']
-    if scope is not None:
-        config_cmd_line.append(scope)
-    else:
-        config_cmd_line.append('--all')
-    config_cmd_line.append('--format=json')
+    """
+    Get the juju charm configuration (scope==None) or individual key,
+    (scope=str).  The returned value is a Python data structure loaded as
+    JSON from the Juju config command.
+
+    :param scope: If set, return the value for the specified key.
+    :type scope: Optional[str]
+    :returns: Either the whole config as a Config, or a key from it.
+    :rtype: Any
+    """
+    global _cache_config
+    config_cmd_line = ['config-get', '--all', '--format=json']
     try:
-        config_data = json.loads(
-            subprocess.check_output(config_cmd_line).decode('UTF-8'))
+        # JSON Decode Exception for Python3.5+
+        exc_json = json.decoder.JSONDecodeError
+    except AttributeError:
+        # JSON Decode Exception for Python2.7 through Python3.4
+        exc_json = ValueError
+    try:
+        if _cache_config is None:
+            config_data = json.loads(
+                subprocess.check_output(config_cmd_line).decode('UTF-8'))
+            _cache_config = Config(config_data)
         if scope is not None:
-            return config_data
-        return Config(config_data)
-    except ValueError:
+            return _cache_config.get(scope)
+        return _cache_config
+    except (exc_json, UnicodeDecodeError) as e:
+        log('Unable to parse output from config-get: config_cmd_line="{}" '
+            'message="{}"'
+            .format(config_cmd_line, str(e)), level=ERROR)
         return None
 
 
diff --git a/charmhelpers/core/services/base.py b/charmhelpers/core/services/base.py
index 345b60d..179ad4f 100644
--- a/charmhelpers/core/services/base.py
+++ b/charmhelpers/core/services/base.py
@@ -307,7 +307,9 @@ class PortManagerCallback(ManagerCallback):
     """
     def __call__(self, manager, service_name, event_name):
         service = manager.get_service(service_name)
-        new_ports = service.get('ports', [])
+        # turn this generator into a list,
+        # as we'll be going over it multiple times
+        new_ports = list(service.get('ports', []))
         port_file = os.path.join(hookenv.charm_dir(), '.{}.ports'.format(service_name))
         if os.path.exists(port_file):
             with open(port_file) as fp:
diff --git a/charmhelpers/core/sysctl.py b/charmhelpers/core/sysctl.py
index 6e413e3..1f188d8 100644
--- a/charmhelpers/core/sysctl.py
+++ b/charmhelpers/core/sysctl.py
@@ -31,18 +31,22 @@ __author__ = 'Jorge Niedbalski R. <jorge.niedbalski@canonical.com>'
 def create(sysctl_dict, sysctl_file):
     """Creates a sysctl.conf file from a YAML associative array
 
-    :param sysctl_dict: a YAML-formatted string of sysctl options eg "{ 'kernel.max_pid': 1337 }"
+    :param sysctl_dict: a dict or YAML-formatted string of sysctl
+                        options eg "{ 'kernel.max_pid': 1337 }"
     :type sysctl_dict: str
     :param sysctl_file: path to the sysctl file to be saved
     :type sysctl_file: str or unicode
     :returns: None
     """
-    try:
-        sysctl_dict_parsed = yaml.safe_load(sysctl_dict)
-    except yaml.YAMLError:
-        log("Error parsing YAML sysctl_dict: {}".format(sysctl_dict),
-            level=ERROR)
-        return
+    if type(sysctl_dict) is not dict:
+        try:
+            sysctl_dict_parsed = yaml.safe_load(sysctl_dict)
+        except yaml.YAMLError:
+            log("Error parsing YAML sysctl_dict: {}".format(sysctl_dict),
+                level=ERROR)
+            return
+    else:
+        sysctl_dict_parsed = sysctl_dict
 
     with open(sysctl_file, "w") as fd:
         for key, value in sysctl_dict_parsed.items():
diff --git a/charmhelpers/core/unitdata.py b/charmhelpers/core/unitdata.py
index 6d7b494..ab55432 100644
--- a/charmhelpers/core/unitdata.py
+++ b/charmhelpers/core/unitdata.py
@@ -166,6 +166,10 @@ class Storage(object):
 
     To support dicts, lists, integer, floats, and booleans values
     are automatically json encoded/decoded.
+
+    Note: to facilitate unit testing, ':memory:' can be passed as the
+    path parameter which causes sqlite3 to only build the db in memory.
+    This should only be used for testing purposes.
     """
     def __init__(self, path=None):
         self.db_path = path
@@ -175,8 +179,9 @@ class Storage(object):
             else:
                 self.db_path = os.path.join(
                     os.environ.get('CHARM_DIR', ''), '.unit-state.db')
-        with open(self.db_path, 'a') as f:
-            os.fchmod(f.fileno(), 0o600)
+        if self.db_path != ':memory:':
+            with open(self.db_path, 'a') as f:
+                os.fchmod(f.fileno(), 0o600)
         self.conn = sqlite3.connect('%s' % self.db_path)
         self.cursor = self.conn.cursor()
         self.revision = None
diff --git a/charmhelpers/fetch/ubuntu.py b/charmhelpers/fetch/ubuntu.py
index 910e96a..653d58f 100644
--- a/charmhelpers/fetch/ubuntu.py
+++ b/charmhelpers/fetch/ubuntu.py
@@ -44,6 +44,7 @@ ARCH_TO_PROPOSED_POCKET = {
     'x86_64': PROPOSED_POCKET,
     'ppc64le': PROPOSED_PORTS_POCKET,
     'aarch64': PROPOSED_PORTS_POCKET,
+    's390x': PROPOSED_PORTS_POCKET,
 }
 CLOUD_ARCHIVE_URL = "http://ubuntu-cloud.archive.canonical.com/ubuntu"
 CLOUD_ARCHIVE_KEY_ID = '5EDB1B62EC4926EA'
diff --git a/tests/charmhelpers/contrib/openstack/amulet/utils.py b/tests/charmhelpers/contrib/openstack/amulet/utils.py
index a60f8fb..84e87f5 100644
--- a/tests/charmhelpers/contrib/openstack/amulet/utils.py
+++ b/tests/charmhelpers/contrib/openstack/amulet/utils.py
@@ -441,7 +441,7 @@ class OpenStackAmuletUtils(AmuletUtils):
             if rel.get('api_version') != str(api_version):
                 raise Exception("api_version not propagated through relation"
                                 " data yet ('{}' != '{}')."
-                                "".format(rel['api_version'], api_version))
+                                "".format(rel.get('api_version'), api_version))
 
     def keystone_configure_api_version(self, sentry_relation_pairs, deployment,
                                        api_version):
diff --git a/tests/charmhelpers/core/hookenv.py b/tests/charmhelpers/core/hookenv.py
index 89f1024..627d8f7 100644
--- a/tests/charmhelpers/core/hookenv.py
+++ b/tests/charmhelpers/core/hookenv.py
@@ -290,7 +290,7 @@ class Config(dict):
         self.implicit_save = True
         self._prev_dict = None
         self.path = os.path.join(charm_dir(), Config.CONFIG_FILE_NAME)
-        if os.path.exists(self.path):
+        if os.path.exists(self.path) and os.stat(self.path).st_size:
             self.load_previous()
         atexit(self._implicit_save)
 
@@ -310,7 +310,11 @@ class Config(dict):
         """
         self.path = path or self.path
         with open(self.path) as f:
-            self._prev_dict = json.load(f)
+            try:
+                self._prev_dict = json.load(f)
+            except ValueError as e:
+                log('Unable to parse previous config data - {}'.format(str(e)),
+                    level=ERROR)
         for k, v in copy.deepcopy(self._prev_dict).items():
             if k not in self:
                 self[k] = v
@@ -354,22 +358,40 @@ class Config(dict):
             self.save()
 
 
-@cached
+_cache_config = None
+
+
 def config(scope=None):
-    """Juju charm configuration"""
-    config_cmd_line = ['config-get']
-    if scope is not None:
-        config_cmd_line.append(scope)
-    else:
-        config_cmd_line.append('--all')
-    config_cmd_line.append('--format=json')
+    """
+    Get the juju charm configuration (scope==None) or individual key,
+    (scope=str).  The returned value is a Python data structure loaded as
+    JSON from the Juju config command.
+
+    :param scope: If set, return the value for the specified key.
+    :type scope: Optional[str]
+    :returns: Either the whole config as a Config, or a key from it.
+    :rtype: Any
+    """
+    global _cache_config
+    config_cmd_line = ['config-get', '--all', '--format=json']
     try:
-        config_data = json.loads(
-            subprocess.check_output(config_cmd_line).decode('UTF-8'))
+        # JSON Decode Exception for Python3.5+
+        exc_json = json.decoder.JSONDecodeError
+    except AttributeError:
+        # JSON Decode Exception for Python2.7 through Python3.4
+        exc_json = ValueError
+    try:
+        if _cache_config is None:
+            config_data = json.loads(
+                subprocess.check_output(config_cmd_line).decode('UTF-8'))
+            _cache_config = Config(config_data)
         if scope is not None:
-            return config_data
-        return Config(config_data)
-    except ValueError:
+            return _cache_config.get(scope)
+        return _cache_config
+    except (exc_json, UnicodeDecodeError) as e:
+        log('Unable to parse output from config-get: config_cmd_line="{}" '
+            'message="{}"'
+            .format(config_cmd_line, str(e)), level=ERROR)
         return None
 
 
diff --git a/tests/charmhelpers/core/services/base.py b/tests/charmhelpers/core/services/base.py
index 345b60d..179ad4f 100644
--- a/tests/charmhelpers/core/services/base.py
+++ b/tests/charmhelpers/core/services/base.py
@@ -307,7 +307,9 @@ class PortManagerCallback(ManagerCallback):
     """
     def __call__(self, manager, service_name, event_name):
         service = manager.get_service(service_name)
-        new_ports = service.get('ports', [])
+        # turn this generator into a list,
+        # as we'll be going over it multiple times
+        new_ports = list(service.get('ports', []))
         port_file = os.path.join(hookenv.charm_dir(), '.{}.ports'.format(service_name))
         if os.path.exists(port_file):
             with open(port_file) as fp:
diff --git a/tests/charmhelpers/core/sysctl.py b/tests/charmhelpers/core/sysctl.py
index 6e413e3..1f188d8 100644
--- a/tests/charmhelpers/core/sysctl.py
+++ b/tests/charmhelpers/core/sysctl.py
@@ -31,18 +31,22 @@ __author__ = 'Jorge Niedbalski R. <jorge.niedbalski@canonical.com>'
 def create(sysctl_dict, sysctl_file):
     """Creates a sysctl.conf file from a YAML associative array
 
-    :param sysctl_dict: a YAML-formatted string of sysctl options eg "{ 'kernel.max_pid': 1337 }"
+    :param sysctl_dict: a dict or YAML-formatted string of sysctl
+                        options eg "{ 'kernel.max_pid': 1337 }"
     :type sysctl_dict: str
     :param sysctl_file: path to the sysctl file to be saved
     :type sysctl_file: str or unicode
     :returns: None
     """
-    try:
-        sysctl_dict_parsed = yaml.safe_load(sysctl_dict)
-    except yaml.YAMLError:
-        log("Error parsing YAML sysctl_dict: {}".format(sysctl_dict),
-            level=ERROR)
-        return
+    if type(sysctl_dict) is not dict:
+        try:
+            sysctl_dict_parsed = yaml.safe_load(sysctl_dict)
+        except yaml.YAMLError:
+            log("Error parsing YAML sysctl_dict: {}".format(sysctl_dict),
+                level=ERROR)
+            return
+    else:
+        sysctl_dict_parsed = sysctl_dict
 
     with open(sysctl_file, "w") as fd:
         for key, value in sysctl_dict_parsed.items():
diff --git a/tests/charmhelpers/core/unitdata.py b/tests/charmhelpers/core/unitdata.py
index 6d7b494..ab55432 100644
--- a/tests/charmhelpers/core/unitdata.py
+++ b/tests/charmhelpers/core/unitdata.py
@@ -166,6 +166,10 @@ class Storage(object):
 
     To support dicts, lists, integer, floats, and booleans values
     are automatically json encoded/decoded.
+
+    Note: to facilitate unit testing, ':memory:' can be passed as the
+    path parameter which causes sqlite3 to only build the db in memory.
+    This should only be used for testing purposes.
     """
     def __init__(self, path=None):
         self.db_path = path
@@ -175,8 +179,9 @@ class Storage(object):
             else:
                 self.db_path = os.path.join(
                     os.environ.get('CHARM_DIR', ''), '.unit-state.db')
-        with open(self.db_path, 'a') as f:
-            os.fchmod(f.fileno(), 0o600)
+        if self.db_path != ':memory:':
+            with open(self.db_path, 'a') as f:
+                os.fchmod(f.fileno(), 0o600)
         self.conn = sqlite3.connect('%s' % self.db_path)
         self.cursor = self.conn.cursor()
         self.revision = None
diff --git a/tox.ini b/tox.ini
index 800d3ed..2b10eb2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -60,7 +60,7 @@ basepython = python2.7
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
-    bundletester -vl DEBUG -r json -o func-results.json gate-basic-xenial --no-destroy
+    bundletester -vl DEBUG -r json -o func-results.json gate-basic-bionic --no-destroy
 
 [testenv:func27-dfs]
 # Charm Functional Test