diff --git a/.zuul.yaml b/.zuul.yaml
index 050bee0875..64ed214e6a 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -116,7 +116,7 @@
     name: controllerconfig-tox-flake8
     parent: tox
     description: Run flake8 tests for controllerconfig
-    nodeset: ubuntu-xenial
+    nodeset: debian-bullseye
     files:
       - controllerconfig/*
     vars:
@@ -127,7 +127,7 @@
     name: controllerconfig-tox-pylint
     parent: tox
     description: Run pylint tests for controllerconfig
-    nodeset: ubuntu-xenial
+    nodeset: debian-bullseye
     required-projects:
       - starlingx/fault
     files:
diff --git a/controllerconfig/controllerconfig/controllerconfig/config_management.py b/controllerconfig/controllerconfig/controllerconfig/config_management.py
index 92a9689c79..734a7037ea 100644
--- a/controllerconfig/controllerconfig/controllerconfig/config_management.py
+++ b/controllerconfig/controllerconfig/controllerconfig/config_management.py
@@ -79,7 +79,7 @@ def configure_management():
     try:
         lldp_interfaces = json.loads(
             lldpcli_show_output)['lldp'][0]['interface']
-    except Exception as e:
+    except Exception:
         lldp_interfaces = {}
     print("DONE")
 
diff --git a/controllerconfig/controllerconfig/controllerconfig/tidy_storage.py b/controllerconfig/controllerconfig/controllerconfig/tidy_storage.py
index ccc0075aba..b2a3351aba 100644
--- a/controllerconfig/controllerconfig/controllerconfig/tidy_storage.py
+++ b/controllerconfig/controllerconfig/controllerconfig/tidy_storage.py
@@ -56,7 +56,7 @@ class OpenStack(object):
             try:
                 with open(openstack_config_file_path) as f:
                     openstack_config_data = \
-                        yaml.load(f)['clouds']['openstack_helm']
+                        yaml.safe_load(f)['clouds']['openstack_helm']
                 self.conf['admin_user'] = \
                     openstack_config_data['auth']['username']
                 self.conf['admin_pwd'] = \
@@ -459,7 +459,7 @@ def tidy_storage(result_file):
                 c_client.volumes.reset_state(
                     c_utils.find_volume(c_client, vol), state='error')
                 print("Setting state to error for volume %s \n" % vol)
-            except Exception as e:
+            except Exception:
                 LOG.error("Failed to update volume to error state for %s"
                           % vol)
                 raise TidyStorageFail("Failed to update volume to error state")
@@ -597,8 +597,8 @@ def tidy_storage(result_file):
                 f.write("\n\n")
                 f.write('{0[0]:<40}{0[1]:<50}\n'.format(['ID', 'NAME']))
                 for snap in snaps_no_backend_vol:
-                        f.write('{0[0]:<40}{0[1]:<50}\n'.format(
-                            [snap.id.encode('utf-8'), snap.name]))
+                    f.write('{0[0]:<40}{0[1]:<50}\n'.format(
+                        [snap.id.encode('utf-8'), snap.name]))
 
                 f.write("\n\n")
 
@@ -620,6 +620,5 @@ def main():
         open(result_file, 'w')
     except IOError:
         raise TidyStorageFail("Failed to open file: %s" % result_file)
-        exit(1)
 
     tidy_storage(result_file)
diff --git a/controllerconfig/controllerconfig/controllerconfig/upgrades/controller.py b/controllerconfig/controllerconfig/controllerconfig/upgrades/controller.py
index 6b73ec1c21..cb389203d7 100644
--- a/controllerconfig/controllerconfig/controllerconfig/upgrades/controller.py
+++ b/controllerconfig/controllerconfig/controllerconfig/upgrades/controller.py
@@ -107,8 +107,8 @@ def get_db_credentials(shared_services, from_release, role=None):
     hiera_path = os.path.join(PLATFORM_PATH, "puppet", from_release,
                               "hieradata")
     static_file = os.path.join(hiera_path, "static.yaml")
-    with open(static_file, 'r') as file:
-        static_config = yaml.load(file)
+    with open(static_file, 'r') as s_file:
+        static_config = yaml.safe_load(s_file)
 
     db_credentials = dict()
     for database, values in db_credential_keys.items():
@@ -411,8 +411,8 @@ def migrate_sysinv_data(from_release, to_release):
     hiera_path = os.path.join(PLATFORM_PATH, "puppet", from_release,
                               "hieradata")
     static_file = os.path.join(hiera_path, "static.yaml")
-    with open(static_file, 'r') as file:
-        static_config = yaml.load(file)
+    with open(static_file, 'r') as s_file:
+        static_config = yaml.safe_load(s_file)
 
     username = static_config["sysinv::db::postgresql::user"]
     password = utils.get_password_from_keyring("sysinv", "database")
@@ -448,8 +448,8 @@ def prepare_postgres_filesystems():
 
     # Create a temporary filesystem for the dumped database
     from_dir = os.path.join(POSTGRES_MOUNT_PATH, "upgrade")
-    stat = os.statvfs(from_dir)
-    db_dump_filesystem_size = str(stat.f_frsize * stat.f_blocks) + "B"
+    statvfs = os.statvfs(from_dir)
+    db_dump_filesystem_size = str(statvfs.f_frsize * statvfs.f_blocks) + "B"
 
     # Move the dumped files to a temporary filesystem.
     os.mkdir(POSTGRES_DUMP_MOUNT_PATH)
@@ -459,8 +459,8 @@ def prepare_postgres_filesystems():
     shutil.move(from_dir, POSTGRES_DUMP_MOUNT_PATH)
 
     # Create a temporary filesystem for the migrated database
-    stat = os.statvfs(POSTGRES_MOUNT_PATH)
-    db_filesystem_size = str(stat.f_frsize * stat.f_blocks) + "B"
+    statvfs = os.statvfs(POSTGRES_MOUNT_PATH)
+    db_filesystem_size = str(statvfs.f_frsize * statvfs.f_blocks) + "B"
     if not os.path.isdir(utils.POSTGRES_PATH):
         os.mkdir(utils.POSTGRES_PATH)
     create_temp_filesystem("cgts-vg", "postgres-temp-lv", utils.POSTGRES_PATH,
@@ -808,7 +808,7 @@ def migrate_hiera_data(from_release, to_release, role=None):
     # Update the static.yaml file
     static_file = os.path.join(constants.HIERADATA_PERMDIR, "static.yaml")
     with open(static_file, 'r') as yaml_file:
-        static_config = yaml.load(yaml_file)
+        static_config = yaml.safe_load(yaml_file)
     static_config.update({
         'platform::params::software_version': SW_VERSION,
         'platform::client::credentials::params::keyring_directory':
@@ -823,7 +823,7 @@ def migrate_hiera_data(from_release, to_release, role=None):
     secure_static_file = os.path.join(
         constants.HIERADATA_PERMDIR, "secure_static.yaml")
     with open(secure_static_file, 'r') as yaml_file:
-        secure_static_config = yaml.load(yaml_file)
+        secure_static_config = yaml.safe_load(yaml_file)
 
     with open(secure_static_file, 'w') as yaml_file:
         yaml.dump(secure_static_config, yaml_file, default_flow_style=False)
diff --git a/controllerconfig/controllerconfig/controllerconfig/upgrades/management.py b/controllerconfig/controllerconfig/controllerconfig/upgrades/management.py
index e66f5a1890..ac328a4ecc 100644
--- a/controllerconfig/controllerconfig/controllerconfig/upgrades/management.py
+++ b/controllerconfig/controllerconfig/controllerconfig/upgrades/management.py
@@ -179,7 +179,7 @@ def prepare_upgrade(from_load, to_load, i_system, mgmt_address):
     admin_conf = os.path.join(tsc.PLATFORM_PATH, "config", to_load,
                               "kubernetes", utils.KUBERNETES_ADMIN_CONF_FILE)
     with open(admin_conf, 'r') as yaml_file:
-        config = yaml.load(yaml_file)
+        config = yaml.safe_load(yaml_file)
 
     for item, values in config.items():
         # update server address in cluster
diff --git a/controllerconfig/controllerconfig/controllerconfig/upgrades/utils.py b/controllerconfig/controllerconfig/controllerconfig/upgrades/utils.py
index 5dc7fe6127..974a766340 100644
--- a/controllerconfig/controllerconfig/controllerconfig/upgrades/utils.py
+++ b/controllerconfig/controllerconfig/controllerconfig/upgrades/utils.py
@@ -216,8 +216,8 @@ def get_upgrade_token(from_release,
     from_hiera_path = os.path.join(PLATFORM_PATH, "puppet", from_release,
                                    "hieradata")
     system_file = os.path.join(from_hiera_path, "system.yaml")
-    with open(system_file, 'r') as file:
-        system_config = yaml.load(file)
+    with open(system_file, 'r') as s_file:
+        system_config = yaml.safe_load(s_file)
 
     # during a controller-1 upgrade, keystone is running
     # on the controller UNIT IP, however the service catalog
@@ -297,8 +297,8 @@ def get_upgrade_data(from_release,
     from_hiera_path = os.path.join(PLATFORM_PATH, "puppet", from_release,
                                    "hieradata")
     system_file = os.path.join(from_hiera_path, "system.yaml")
-    with open(system_file, 'r') as file:
-        system_config_from_release = yaml.load(file)
+    with open(system_file, 'r') as s_file:
+        system_config_from_release = yaml.safe_load(s_file)
 
     # Get keystone region
     keystone_region = system_config_from_release.get(
@@ -329,11 +329,11 @@ def add_upgrade_entries_to_hiera_data(from_release):
 
     # Get the hiera data for this release
     filepath = os.path.join(path, filename)
-    with open(filepath, 'r') as file:
-        config = yaml.load(file)
+    with open(filepath, 'r') as c_file:
+        config = yaml.safe_load(c_file)
     secure_filepath = os.path.join(path, secure_filename)
-    with open(secure_filepath, 'r') as file:
-        secure_config = yaml.load(file)
+    with open(secure_filepath, 'r') as s_file:
+        secure_config = yaml.safe_load(s_file)
 
     # File for system.yaml
     # This is needed for adding new service account and endpoints
diff --git a/controllerconfig/controllerconfig/controllerconfig/utils.py b/controllerconfig/controllerconfig/controllerconfig/utils.py
index f5fece9ad7..2f81a475ea 100644
--- a/controllerconfig/controllerconfig/controllerconfig/utils.py
+++ b/controllerconfig/controllerconfig/controllerconfig/utils.py
@@ -264,7 +264,7 @@ def persist_config():
 
 def apply_banner_customization():
     """ Apply and Install banners provided by the user """
-    """ execute: /usr/sbin/apply_banner_customization """
+    # execute: /usr/sbin/apply_banner_customization
     logfile = "/tmp/apply_banner_customization.log"
     try:
         with open(logfile, "w") as blog:
diff --git a/controllerconfig/controllerconfig/pylint.rc b/controllerconfig/controllerconfig/pylint.rc
index ebfb70c333..3d262e8a67 100755
--- a/controllerconfig/controllerconfig/pylint.rc
+++ b/controllerconfig/controllerconfig/pylint.rc
@@ -17,91 +17,6 @@ load-plugins=
 
 
 [MESSAGES CONTROL]
-# Enable the message, report, category or checker with the given id(s). You can
-# either give multiple identifier separated by comma (,) or put this option
-# multiple time.
-#
-# Python3 checker:
-#
-# E1601: print-statement
-# E1602: parameter-unpacking
-# E1603: unpacking-in-except
-# E1604: old-raise-syntax
-# E1605: backtick
-# E1606: long-suffix
-# E1607: old-ne-operator
-# E1608: old-octal-literal
-# E1609: import-star-module-level
-# E1610: non-ascii-bytes-literal
-# E1611: invalid-unicode-literal
-# W1601: apply-builtin
-# W1602: basestring-builtin
-# W1603: buffer-builtin
-# W1604: cmp-builtin
-# W1605: coerce-builtin
-# W1606: execfile-builtin
-# W1607: file-builtin
-# W1608: long-builtin
-# W1609: raw_input-builtin
-# W1610: reduce-builtin
-# W1611: standarderror-builtin
-# W1612: unicode-builtin
-# W1613: xrange-builtin
-# W1614: coerce-method
-# W1615: delslice-method
-# W1616: getslice-method
-# W1617: setslice-method
-# W1618: no-absolute-import
-# W1619: old-division
-# W1620: dict-iter-method
-# W1621: dict-view-method
-# W1622: next-method-called
-# W1623: metaclass-assignment
-# W1624: indexing-exception
-# W1625: raising-string
-# W1626: reload-builtin
-# W1627: oct-method
-# W1628: hex-method
-# W1629: nonzero-method
-# W1630: cmp-method
-# W1632: input-builtin
-# W1633: round-builtin
-# W1634: intern-builtin
-# W1635: unichr-builtin
-# W1636: map-builtin-not-iterating
-# W1637: zip-builtin-not-iterating
-# W1638: range-builtin-not-iterating
-# W1639: filter-builtin-not-iterating
-# W1640: using-cmp-argument
-# W1641: eq-without-hash
-# W1642: div-method
-# W1643: idiv-method
-# W1644: rdiv-method
-# W1645: exception-message-attribute
-# W1646: invalid-str-codec
-# W1647: sys-max-int
-# W1648: bad-python3-import
-# W1649: deprecated-string-function
-# W1650: deprecated-str-translate-call
-# W1651: deprecated-itertools-function
-# W1652: deprecated-types-field
-# W1653: next-method-defined
-# W1654: dict-items-not-iterating
-# W1655: dict-keys-not-iterating
-# W1656: dict-values-not-iterating
-# W1657: deprecated-operator-function
-# W1658: deprecated-urllib-function
-# W1659: xreadlines-attribute
-# W1660: deprecated-sys-function
-# W1661: exception-escape
-# W1662: comprehension-escape
-enable=E1603,E1609,E1610,E1602,E1606,E1608,E1607,E1605,E1604,E1601,E1611,W1652,
-       W1651,W1649,W1657,W1660,W1658,W1659,W1623,W1622,W1620,W1621,W1645,W1641,
-       W1624,W1648,W1625,W1611,W1662,W1661,W1650,W1640,W1630,W1614,W1615,W1642,
-       W1616,W1628,W1643,W1629,W1627,W1644,W1617,W1601,W1602,W1603,W1604,W1605,
-       W1654,W1655,W1656,W1619,W1606,W1607,W1639,W1618,W1632,W1634,W1608,W1636,
-       W1653,W1646,W1638,W1609,W1610,W1626,W1633,W1647,W1635,W1612,W1613,W1637
-
 # Disable the message, report, category or checker with the given id(s). You
 # can either give multiple identifier separated by comma (,) or put this option
 # multiple time (only on the command line, not in the configuration file where
@@ -113,17 +28,10 @@ enable=E1603,E1609,E1610,E1602,E1606,E1608,E1607,E1605,E1604,E1601,E1611,W1652,
 # We are not disabling (F)atal, (E)rror
 # The following suppressed warnings should be fixed:
 # fixme: (notes, xxx, fixme)
-# W0101: unreachable-code
-# W0105: pointless-string-statement
-# W0311: bad-indentation
-# W0403: relative-import
 # W0613: unused-argument
-# W0621: redefined-outer-name
 # W0622: redefined-builtin
 # W0703: broad-except
-# W1501: bad-open-mode
-# W1618: no-absolute-import
-disable=C, R, fixme, W0101, W0105, W0311, W0403, W0613, W0621, W0622, W0703, W1501, W1618
+disable=C, R, fixme, W0613, W0622, W0703
 
 
 [REPORTS]
diff --git a/controllerconfig/controllerconfig/test-requirements.txt b/controllerconfig/controllerconfig/test-requirements.txt
index de056a464e..e7dc60ffe5 100644
--- a/controllerconfig/controllerconfig/test-requirements.txt
+++ b/controllerconfig/controllerconfig/test-requirements.txt
@@ -1,12 +1,15 @@
-hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
-pytest
-mockproc>= 0.3.1 # BSD
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
+hacking>=1.1.0,<=2.0.0 # Apache-2.0
 coverage>=3.6
-PyYAML>=3.10.0 # MIT
+isort<5
+mockproc>= 0.3.1 # BSD
 os-testr>=0.8.0 # Apache-2.0
+pylint<2.4.0 # GPLv2
+pytest
+PyYAML>=3.10.0 # MIT
 stestr>=1.0.0 # Apache-2.0
 testresources>=0.2.4 # Apache-2.0/BSD
 testrepository>=0.0.18 # Apache-2.0/BSD
-isort<5;python_version>="3.0"
-pylint<2.1.0;python_version<"3.0" # GPLv2
-pylint<2.4.0;python_version>="3.0" # GPLv2
diff --git a/controllerconfig/controllerconfig/tox.ini b/controllerconfig/controllerconfig/tox.ini
index afa6079a96..ff456a94fc 100644
--- a/controllerconfig/controllerconfig/tox.ini
+++ b/controllerconfig/controllerconfig/tox.ini
@@ -4,17 +4,16 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = flake8, pylint, py27, py36, py39
+envlist = flake8, pylint, py39
 # Tox does not work if the path to the workdir is too long, so move it to /tmp
 toxworkdir = /tmp/{env:USER}_cctox
 stxdir = {toxinidir}/../../..
 
 [testenv]
 allowlist_externals = find
-install_command = pip install \
-    --no-cache-dir \
-    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/stable/stein/upper-constraints.txt} \
-    {opts} {packages}
+basepython = python3
+commands =
+  find . -type f -name "*.pyc" -delete
 
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
@@ -22,52 +21,28 @@ deps = -r{toxinidir}/requirements.txt
        -e{[tox]stxdir}/config/tsconfig/tsconfig
        -e{[tox]stxdir}/config/sysinv/sysinv/sysinv
 
-commands =
-  find . -type f -name "*.pyc" -delete
+install_command = pip install \
+    --no-cache-dir \
+    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/starlingx/root/raw/branch/master/build-tools/requirements/debian/upper-constraints.txt} \
+    {opts} {packages}
 
 [testenv:venv]
 commands = {posargs}
 
-[testenv:py27]
-basepython = python2.7
-deps = {[testenv]deps}
-passenv = CURL_CA_BUNDLE
-commands =
-  {[testenv]commands}
-  stestr run {posargs}
-  stestr slowest
+[testenv:flake8]
+deps = -r{toxinidir}/test-requirements.txt
+commands = flake8 {posargs}
 
-[testenv:py36]
-basepython = python3.6
-deps = {[testenv]deps}
+[testenv:py39]
+basepython = python3.9
 commands =
   {[testenv]commands}
   stestr run {posargs}
   stestr slowest
 
 [testenv:pylint]
-basepython = python3
-deps = {[testenv]deps}
-        pylint
-
 commands = pylint {posargs} controllerconfig --rcfile=./pylint.rc --extension-pkg-whitelist=netifaces
 
-[testenv:flake8]
-basepython = python3
-deps = -r{toxinidir}/test-requirements.txt
-commands = flake8 {posargs}
-
-[testenv:py39]
-basepython = python3.9
-install_command = pip install \
-    --no-cache-dir \
-    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/starlingx/root/raw/branch/master/build-tools/requirements/debian/upper-constraints.txt} \
-    {opts} {packages}
-commands =
-  {[testenv]commands}
-  stestr run {posargs}
-  stestr slowest
-
 [flake8]
 # H series are hacking
 # H101: Use TODO(NAME)
@@ -77,16 +52,17 @@ commands =
 # H401: docstring should not start with a space
 # H404: multi line docstring should start without a leading new line
 # H405: multi line docstring summary not separated with an empty line
-ignore = H101,H102,H104,H306,H401,H404,H405
+#
+# W504 line break after binary operator
+# W605 invalid escape sequence 
+ignore = H101,H102,H104,H306,H401,H404,H405,
+         W504,W605
 exclude = build
 
 [testenv:cover]
-basepython = python3
-deps = {[testenv]deps}
-
+basepython = python3.9
 commands =
   coverage erase
   python setup.py testr --coverage --testr-args='{posargs}'
   coverage xml
   coverage report
-
diff --git a/controllerconfig/controllerconfig/upgrade-scripts/09-adjust-debian-multipath-disks-support.py b/controllerconfig/controllerconfig/upgrade-scripts/09-adjust-debian-multipath-disks-support.py
index a7d75edbe7..7c698cac5c 100755
--- a/controllerconfig/controllerconfig/upgrade-scripts/09-adjust-debian-multipath-disks-support.py
+++ b/controllerconfig/controllerconfig/upgrade-scripts/09-adjust-debian-multipath-disks-support.py
@@ -38,8 +38,8 @@ def main():
     )
     res = 0
     if action == "migrate" and (
-        from_release == "21.12"
-        and to_release == "22.12"
+        from_release == "21.12" and
+        to_release == "22.12"
     ):
         if not is_multipath():
             LOG.info("Multipath not detected, nothing to do")
@@ -230,5 +230,6 @@ def transform_part_device_path(path):
         return "{}wwn-0x{}-{}".format(result[1], result[3], result[2])
     return path
 
+
 if __name__ == "__main__":
     sys.exit(main())
diff --git a/controllerconfig/controllerconfig/upgrade-scripts/68-pod-security-admission-controller-labels.py b/controllerconfig/controllerconfig/upgrade-scripts/68-pod-security-admission-controller-labels.py
index e09f2c21a0..d7c8542fae 100644
--- a/controllerconfig/controllerconfig/upgrade-scripts/68-pod-security-admission-controller-labels.py
+++ b/controllerconfig/controllerconfig/upgrade-scripts/68-pod-security-admission-controller-labels.py
@@ -45,7 +45,7 @@ def add_pod_security_admission_controller_labels():
 
         namespaces_output = subprocess.check_output(cmd).decode("utf-8")
 
-    except Exception as exc:
+    except Exception:
         LOG.error('Command failed:\n %s' % (cmd))
         raise Exception('Cannot get namespaces for pod security labels')
 
diff --git a/controllerconfig/controllerconfig/upgrade-scripts/97-reset-config-target.py b/controllerconfig/controllerconfig/upgrade-scripts/97-reset-config-target.py
index 80d60283ab..78f92fac4f 100755
--- a/controllerconfig/controllerconfig/upgrade-scripts/97-reset-config-target.py
+++ b/controllerconfig/controllerconfig/upgrade-scripts/97-reset-config-target.py
@@ -54,7 +54,7 @@ def reset_config_target():
     conn = psycopg2.connect("dbname=sysinv user=postgres")
     with conn:
         with conn.cursor(cursor_factory=RealDictCursor) as cur:
-                cur.execute("update i_host set config_target=NULL",)
+            cur.execute("update i_host set config_target=NULL",)
 
     LOG.info("Reset host config_target completed")