diff --git a/octavia/amphorae/backends/agent/api_server/amphora_info.py b/octavia/amphorae/backends/agent/api_server/amphora_info.py
index 27ed98d23c..adbfe61c44 100644
--- a/octavia/amphorae/backends/agent/api_server/amphora_info.py
+++ b/octavia/amphorae/backends/agent/api_server/amphora_info.py
@@ -105,7 +105,7 @@ class AmphoraInfo:
     def _get_version_of_installed_package(self, name):
 
         cmd = self._osutils.cmd_get_version_of_installed_package(name)
-        version = subprocess.check_output(cmd.split())
+        version = subprocess.check_output(cmd.split(), encoding='utf-8')
         return version
 
     def _count_haproxy_processes(self, lb_list):
diff --git a/octavia/amphorae/backends/agent/api_server/keepalived.py b/octavia/amphorae/backends/agent/api_server/keepalived.py
index cdfc36d93a..081870f5fb 100644
--- a/octavia/amphorae/backends/agent/api_server/keepalived.py
+++ b/octavia/amphorae/backends/agent/api_server/keepalived.py
@@ -121,7 +121,8 @@ class Keepalived:
         if init_enable_cmd is not None:
             try:
                 subprocess.check_output(init_enable_cmd.split(),
-                                        stderr=subprocess.STDOUT)
+                                        stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.debug('Failed to enable octavia-keepalived service: '
                           '%(err)s %(output)s', {'err': e, 'output': e.output})
@@ -160,7 +161,8 @@ class Keepalived:
         cmd = f"/usr/sbin/service octavia-keepalived {action}"
 
         try:
-            subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+            subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                    encoding='utf-8')
         except subprocess.CalledProcessError as e:
             LOG.debug('Failed to %s octavia-keepalived service: %s %s',
                       action, e, e.output)
diff --git a/octavia/amphorae/backends/agent/api_server/keepalivedlvs.py b/octavia/amphorae/backends/agent/api_server/keepalivedlvs.py
index 4bb6915930..2f9e11f3e9 100644
--- a/octavia/amphorae/backends/agent/api_server/keepalivedlvs.py
+++ b/octavia/amphorae/backends/agent/api_server/keepalivedlvs.py
@@ -143,7 +143,8 @@ class KeepalivedLvs(lvs_listener_base.LvsListenerApiServerBase):
             init_enable_cmd = f"insserv {file_path}"
             try:
                 subprocess.check_output(init_enable_cmd.split(),
-                                        stderr=subprocess.STDOUT)
+                                        stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.debug('Failed to enable '
                           'octavia-keepalivedlvs service: '
@@ -220,7 +221,8 @@ class KeepalivedLvs(lvs_listener_base.LvsListenerApiServerBase):
                f"octavia-keepalivedlvs-{listener_id} {action}")
 
         try:
-            subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+            subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                    encoding='utf-8')
         except subprocess.CalledProcessError as e:
             LOG.debug('Failed to %s keepalivedlvs listener %s',
                       listener_id + ' : ' + action, e)
@@ -281,7 +283,8 @@ class KeepalivedLvs(lvs_listener_base.LvsListenerApiServerBase):
             cmd = (f"/usr/sbin/service "
                    f"octavia-keepalivedlvs-{listener_id} stop")
             try:
-                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.error("Failed to stop keepalivedlvs service: %s", e)
                 return webob.Response(json={
@@ -309,7 +312,8 @@ class KeepalivedLvs(lvs_listener_base.LvsListenerApiServerBase):
             init_disable_cmd = f"insserv -r {init_path}"
             try:
                 subprocess.check_output(init_disable_cmd.split(),
-                                        stderr=subprocess.STDOUT)
+                                        stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.error("Failed to disable "
                           "octavia-keepalivedlvs-%(list)s service: "
diff --git a/octavia/amphorae/backends/agent/api_server/loadbalancer.py b/octavia/amphorae/backends/agent/api_server/loadbalancer.py
index f2a9287b6c..d7ef0d0b86 100644
--- a/octavia/amphorae/backends/agent/api_server/loadbalancer.py
+++ b/octavia/amphorae/backends/agent/api_server/loadbalancer.py
@@ -134,7 +134,8 @@ class Loadbalancer:
             haproxy_ug=consts.HAPROXY_USER_GROUP_CFG)
 
         try:
-            subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+            subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                    encoding='utf-8')
         except subprocess.CalledProcessError as e:
             LOG.error("Failed to verify haproxy file: %s %s", e, e.output)
             # Save the last config that failed validation for debugging
@@ -213,7 +214,8 @@ class Loadbalancer:
         elif init_system == consts.INIT_SYSVINIT:
             try:
                 subprocess.check_output(init_enable_cmd.split(),
-                                        stderr=subprocess.STDOUT)
+                                        stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.error("Failed to enable haproxy-%(lb_id)s service: "
                           "%(err)s %(out)s", {'lb_id': lb_id, 'err': e,
@@ -286,11 +288,12 @@ class Loadbalancer:
                 lb_id=lb_id, action=action))
 
             try:
-                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 # Mitigation for
                 # https://bugs.launchpad.net/octavia/+bug/2054666
-                if (b'is not active, cannot reload.' in e.output and
+                if ('is not active, cannot reload.' in e.output and
                         action == consts.AMP_ACTION_RELOAD):
 
                     saved_exc = e
@@ -312,20 +315,21 @@ class Loadbalancer:
                                 "was reloaded, check the haproxy logs for "
                                 "more details.")
                     break
-                if b'Job is already running' not in e.output:
+                if 'Job is already running' not in e.output:
                     LOG.debug(
                         "Failed to %(action)s haproxy-%(lb_id)s service: "
                         "%(err)s %(out)s", {'action': action, 'lb_id': lb_id,
                                             'err': e, 'out': e.output})
                     return webob.Response(json={
                         'message': f"Error {action}ing haproxy",
-                        'details': e.output}, status=500)
+                        'details': e.output
+                    }, status=500)
             break
         else:
             # no break, we reach the retry limit for reloads
             return webob.Response(json={
                 'message': f"Error {action}ing haproxy",
-                'details': saved_exc.output if saved_exc else ''}, status=500)
+                'details': saved_exc.output}, status=500)
 
         # If we are not in active/standby we need to send an IP
         # advertisement (GARP or NA). Keepalived handles this for
@@ -360,7 +364,8 @@ class Loadbalancer:
                 os.path.join('/proc', util.get_haproxy_pid(lb_id))):
             cmd = f"/usr/sbin/service haproxy-{lb_id} stop"
             try:
-                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.error("Failed to stop haproxy-%s service: %s %s",
                           lb_id, e, e.output)
@@ -401,7 +406,8 @@ class Loadbalancer:
             init_disable_cmd = f"insserv -r {init_path}"
             try:
                 subprocess.check_output(init_disable_cmd.split(),
-                                        stderr=subprocess.STDOUT)
+                                        stderr=subprocess.STDOUT,
+                                        encoding='utf-8')
             except subprocess.CalledProcessError as e:
                 LOG.error("Failed to disable haproxy-%(lb_id)s service: "
                           "%(err)s %(out)s", {'lb_id': lb_id, 'err': e,
diff --git a/octavia/amphorae/backends/agent/api_server/osutils.py b/octavia/amphorae/backends/agent/api_server/osutils.py
index a1e55584e6..169aa38cae 100644
--- a/octavia/amphorae/backends/agent/api_server/osutils.py
+++ b/octavia/amphorae/backends/agent/api_server/osutils.py
@@ -89,8 +89,9 @@ class BaseOS:
         LOG.debug("Executing: %s", cmd)
         try:
             out = subprocess.check_output(cmd.split(),
-                                          stderr=subprocess.STDOUT)
-            for line in out.decode('utf-8').split('\n'):
+                                          stderr=subprocess.STDOUT,
+                                          encoding='utf-8')
+            for line in out.split('\n'):
                 LOG.debug(line)
         except subprocess.CalledProcessError as e:
             LOG.error('Failed to set up %s due to error: %s %s', interface,
diff --git a/octavia/amphorae/backends/agent/api_server/util.py b/octavia/amphorae/backends/agent/api_server/util.py
index 77500700ea..aff55d47ed 100644
--- a/octavia/amphorae/backends/agent/api_server/util.py
+++ b/octavia/amphorae/backends/agent/api_server/util.py
@@ -269,7 +269,8 @@ def install_netns_systemd_service():
 def run_systemctl_command(command, service):
     cmd = f"systemctl {command} {service}"
     try:
-        subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
+        subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
+                                encoding='utf-8')
     except subprocess.CalledProcessError as e:
         LOG.error("Failed to %(cmd)s %(srvc)s service: "
                   "%(err)s %(out)s", {'cmd': command, 'srvc': service,
diff --git a/octavia/amphorae/backends/health_daemon/health_daemon.py b/octavia/amphorae/backends/health_daemon/health_daemon.py
index 50774ac526..9d64e94355 100644
--- a/octavia/amphorae/backends/health_daemon/health_daemon.py
+++ b/octavia/amphorae/backends/health_daemon/health_daemon.py
@@ -15,6 +15,7 @@
 #    under the License.
 
 import errno
+import json
 import os
 import queue
 import stat
@@ -22,7 +23,6 @@ import time
 
 from oslo_config import cfg
 from oslo_log import log as logging
-import simplejson
 
 from octavia.amphorae.backends.agent.api_server import util
 from octavia.amphorae.backends.health_daemon import health_sender
@@ -73,8 +73,8 @@ def get_counters():
     global COUNTERS
     if COUNTERS is None:
         try:
-            COUNTERS = simplejson.load(get_counters_file()) or {}
-        except (simplejson.JSONDecodeError, AttributeError):
+            COUNTERS = json.load(get_counters_file()) or {}
+        except (json.JSONDecodeError, AttributeError):
             COUNTERS = {}
     return COUNTERS
 
@@ -84,7 +84,7 @@ def persist_counters():
     if COUNTERS is None:
         return
     try:
-        stats = simplejson.dumps(COUNTERS)
+        stats = json.dumps(COUNTERS)
         counters_file = get_counters_file()
         counters_file.truncate(0)
         counters_file.write(stats)
diff --git a/octavia/amphorae/backends/utils/interface_file.py b/octavia/amphorae/backends/utils/interface_file.py
index 1da9bc0347..63a01b8aee 100644
--- a/octavia/amphorae/backends/utils/interface_file.py
+++ b/octavia/amphorae/backends/utils/interface_file.py
@@ -13,11 +13,11 @@
 # under the License.
 
 import ipaddress
+import json
 import os
 import stat
 
 from oslo_config import cfg
-import simplejson
 
 from octavia.common import constants as consts
 
@@ -45,11 +45,11 @@ class InterfaceFile:
 
     @classmethod
     def load(cls, fp):
-        return simplejson.load(fp)
+        return json.load(fp)
 
     @classmethod
     def dump(cls, obj):
-        return simplejson.dumps(obj)
+        return json.dumps(obj)
 
     @classmethod
     def from_file(cls, filename):
diff --git a/octavia/amphorae/drivers/haproxy/rest_api_driver.py b/octavia/amphorae/drivers/haproxy/rest_api_driver.py
index a1d85fc35c..ae23c95712 100644
--- a/octavia/amphorae/drivers/haproxy/rest_api_driver.py
+++ b/octavia/amphorae/drivers/haproxy/rest_api_driver.py
@@ -14,6 +14,7 @@
 # under the License.
 import functools
 import hashlib
+import json
 import os
 import ssl
 import time
@@ -24,7 +25,6 @@ from oslo_context import context as oslo_context
 from oslo_log import log as logging
 from oslo_utils.secretutils import md5
 import requests
-import simplejson
 from stevedore import driver as stevedore_driver
 
 from octavia.amphorae.driver_exceptions import exceptions as driver_except
@@ -723,7 +723,7 @@ class AmphoraAPIClientBase:
                         if 'No suitable network interface found' in json_data:
                             LOG.debug("Amphora network interface not found.")
                             raise requests.ConnectionError
-                    except simplejson.JSONDecodeError:  # if r.json() fails
+                    except json.JSONDecodeError:  # if r.json() fails
                         pass  # TODO(rm_work) Should we do something?
                 return r
             except (requests.ConnectionError, requests.Timeout) as e:
diff --git a/octavia/tests/functional/amphorae/backend/agent/api_server/test_keepalivedlvs.py b/octavia/tests/functional/amphorae/backend/agent/api_server/test_keepalivedlvs.py
index 9094cb6e61..a3be326cd6 100644
--- a/octavia/tests/functional/amphorae/backend/agent/api_server/test_keepalivedlvs.py
+++ b/octavia/tests/functional/amphorae/backend/agent/api_server/test_keepalivedlvs.py
@@ -314,7 +314,8 @@ class KeepalivedLvsTestCase(base.TestCase):
         cmd = ("/usr/sbin/service octavia-keepalivedlvs-{listener_id}"
                " {action}".format(listener_id=self.FAKE_ID, action='start'))
         mock_check_output.assert_called_once_with(cmd.split(),
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         self.assertEqual(202, res.status_code)
 
         res = self.test_keepalivedlvs.manage_lvs_listener(self.FAKE_ID,
@@ -347,8 +348,10 @@ class KeepalivedLvsTestCase(base.TestCase):
         cmd2 = ("systemctl disable "
                 "octavia-keepalivedlvs-{list}".format(list=self.FAKE_ID))
         calls = [
-            mock.call(cmd1.split(), stderr=subprocess.STDOUT),
-            mock.call(cmd2.split(), stderr=subprocess.STDOUT)
+            mock.call(cmd1.split(), stderr=subprocess.STDOUT,
+                      encoding='utf-8'),
+            mock.call(cmd2.split(), stderr=subprocess.STDOUT,
+                      encoding='utf-8')
         ]
         m_check_output.assert_has_calls(calls)
         self.assertEqual(200, res.status_code)
diff --git a/octavia/tests/functional/amphorae/backend/agent/api_server/test_server.py b/octavia/tests/functional/amphorae/backend/agent/api_server/test_server.py
index f5f3ad31ae..52bc8dc57f 100644
--- a/octavia/tests/functional/amphorae/backend/agent/api_server/test_server.py
+++ b/octavia/tests/functional/amphorae/backend/agent/api_server/test_server.py
@@ -38,7 +38,7 @@ import octavia.tests.unit.base as base
 
 
 AMP_AGENT_CONF_PATH = '/etc/octavia/amphora-agent.conf'
-RANDOM_ERROR = b'random error'
+RANDOM_ERROR = 'random error'
 OK = dict(message='OK')
 FAKE_INTERFACE = 'eth33'
 
@@ -137,7 +137,7 @@ class TestServerTestCase(base.TestCase):
                     haproxy_ug=consts.HAPROXY_USER_GROUP_CFG,
                     peer=(octavia_utils.
                           base64_sha1_string('amp_123').rstrip('='))).split(),
-                stderr=-2)
+                stderr=subprocess.STDOUT, encoding='utf-8')
             mock_rename.assert_called_with(
                 '/var/lib/octavia/123/haproxy.cfg.new',
                 '/var/lib/octavia/123/haproxy.cfg')
@@ -145,11 +145,11 @@ class TestServerTestCase(base.TestCase):
         if init_system == consts.INIT_SYSTEMD:
             mock_subprocess.assert_any_call(
                 "systemctl enable haproxy-123".split(),
-                stderr=subprocess.STDOUT)
+                stderr=subprocess.STDOUT, encoding='utf-8')
         elif init_system == consts.INIT_SYSVINIT:
             mock_subprocess.assert_any_call(
                 "insserv /etc/init.d/haproxy-123".split(),
-                stderr=subprocess.STDOUT)
+                stderr=subprocess.STDOUT, encoding='utf-8')
         else:
             self.assertIn(init_system, consts.VALID_INIT_SYSTEMS)
 
@@ -243,7 +243,7 @@ class TestServerTestCase(base.TestCase):
                     haproxy_ug=consts.HAPROXY_USER_GROUP_CFG,
                     peer=(octavia_utils.
                           base64_sha1_string('amp_123').rstrip('='))).split(),
-                stderr=-2)
+                stderr=subprocess.STDOUT, encoding='utf-8')
             mock_rename.assert_called_with(
                 '/var/lib/octavia/123/haproxy.cfg.new',
                 '/var/lib/octavia/123/haproxy.cfg.new-failed')
@@ -321,7 +321,8 @@ class TestServerTestCase(base.TestCase):
                         ' 123 started'},
             jsonutils.loads(rv.data.decode('utf-8')))
         mock_subprocess.assert_called_with(
-            ['/usr/sbin/service', 'haproxy-123', 'start'], stderr=-2)
+            ['/usr/sbin/service', 'haproxy-123', 'start'],
+            stderr=subprocess.STDOUT, encoding='utf-8')
 
         mock_exists.return_value = True
         mock_subprocess.side_effect = subprocess.CalledProcessError(
@@ -336,10 +337,11 @@ class TestServerTestCase(base.TestCase):
         self.assertEqual(
             {
                 'message': 'Error starting haproxy',
-                'details': RANDOM_ERROR.decode('utf-8'),
+                'details': RANDOM_ERROR,
             }, jsonutils.loads(rv.data.decode('utf-8')))
         mock_subprocess.assert_called_with(
-            ['/usr/sbin/service', 'haproxy-123', 'start'], stderr=-2)
+            ['/usr/sbin/service', 'haproxy-123', 'start'],
+            stderr=subprocess.STDOUT, encoding='utf-8')
 
     def test_ubuntu_reload(self):
         self._test_reload(consts.UBUNTU)
@@ -377,7 +379,8 @@ class TestServerTestCase(base.TestCase):
              'details': 'Listener 123 reloaded'},
             jsonutils.loads(rv.data.decode('utf-8')))
         mock_subprocess.assert_called_with(
-            ['/usr/sbin/service', 'haproxy-123', 'reload'], stderr=-2)
+            ['/usr/sbin/service', 'haproxy-123', 'reload'],
+            stderr=subprocess.STDOUT, encoding='utf-8')
 
         # Process not running so start
         mock_exists.return_value = True
@@ -395,7 +398,8 @@ class TestServerTestCase(base.TestCase):
                         ' 123 started'},
             jsonutils.loads(rv.data.decode('utf-8')))
         mock_subprocess.assert_called_with(
-            ['/usr/sbin/service', 'haproxy-123', 'start'], stderr=-2)
+            ['/usr/sbin/service', 'haproxy-123', 'start'],
+            stderr=subprocess.STDOUT, encoding='utf-8')
 
     def test_ubuntu_info(self):
         self._test_info(consts.UBUNTU)
@@ -604,19 +608,22 @@ class TestServerTestCase(base.TestCase):
                          jsonutils.loads(rv.data.decode('utf-8')))
         mock_pid.assert_called_once_with('123')
         mock_check_output.assert_any_call(
-            ['/usr/sbin/service', 'haproxy-123', 'stop'], stderr=-2)
+            ['/usr/sbin/service', 'haproxy-123', 'stop'],
+            stderr=subprocess.STDOUT, encoding='utf-8')
 
         if init_system == consts.INIT_SYSTEMD:
             mock_check_output.assert_any_call(
                 "systemctl disable haproxy-123".split(),
-                stderr=subprocess.STDOUT)
+                stderr=subprocess.STDOUT,
+                encoding='utf-8')
         elif init_system == consts.INIT_UPSTART:
             mock_remove.assert_any_call(consts.UPSTART_DIR +
                                         '/haproxy-123.conf')
         elif init_system == consts.INIT_SYSVINIT:
             mock_check_output.assert_any_call(
                 "insserv -r /etc/init.d/haproxy-123".split(),
-                stderr=subprocess.STDOUT)
+                stderr=subprocess.STDOUT,
+                encoding='utf-8')
         else:
             self.assertIn(init_system, consts.VALID_INIT_SYSTEMS)
 
@@ -634,19 +641,22 @@ class TestServerTestCase(base.TestCase):
                          jsonutils.loads(rv.data.decode('utf-8')))
         mock_pid.assert_called_with('123')
         mock_check_output.assert_any_call(
-            ['/usr/sbin/service', 'haproxy-123', 'stop'], stderr=-2)
+            ['/usr/sbin/service', 'haproxy-123', 'stop'],
+            stderr=subprocess.STDOUT, encoding='utf-8')
 
         if init_system == consts.INIT_SYSTEMD:
             mock_check_output.assert_any_call(
                 "systemctl disable haproxy-123".split(),
-                stderr=subprocess.STDOUT)
+                stderr=subprocess.STDOUT,
+                encoding='utf-8')
         elif init_system == consts.INIT_UPSTART:
             mock_remove.assert_any_call(consts.UPSTART_DIR +
                                         '/haproxy-123.conf')
         elif init_system == consts.INIT_SYSVINIT:
             mock_check_output.assert_any_call(
                 "insserv -r /etc/init.d/haproxy-123".split(),
-                stderr=subprocess.STDOUT)
+                stderr=subprocess.STDOUT,
+                encoding='utf-8')
         else:
             self.assertIn(init_system, consts.VALID_INIT_SYSTEMS)
 
@@ -1014,7 +1024,7 @@ class TestServerTestCase(base.TestCase):
             for idx in range(test_int_num)]
         mock_isfile.return_value = True
 
-        mock_check_output.return_value = b"1\n2\n3\n"
+        mock_check_output.return_value = "1\n2\n3\n"
 
         test_int_num = str(test_int_num)
 
@@ -1145,7 +1155,8 @@ class TestServerTestCase(base.TestCase):
 
             mock_check_output.assert_called_with(
                 ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                 'amphora-interface', 'up', 'eth' + test_int_num], stderr=-2)
+                 'amphora-interface', 'up', 'eth' + test_int_num],
+                stderr=subprocess.STDOUT, encoding='utf-8')
 
         # fixed IPs happy path
         port_info = {'mac_address': '123', 'mtu': 1450, 'fixed_ips': [
@@ -1215,7 +1226,8 @@ class TestServerTestCase(base.TestCase):
 
             mock_check_output.assert_called_with(
                 ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                 'amphora-interface', 'up', 'eth' + test_int_num], stderr=-2)
+                 'amphora-interface', 'up', 'eth' + test_int_num],
+                stderr=subprocess.STDOUT, encoding='utf-8')
 
         # fixed IPs happy path IPv6
         port_info = {'mac_address': '123', 'mtu': 1450, 'fixed_ips': [
@@ -1285,7 +1297,8 @@ class TestServerTestCase(base.TestCase):
 
             mock_check_output.assert_called_with(
                 ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                 'amphora-interface', 'up', 'eth' + test_int_num], stderr=-2)
+                 'amphora-interface', 'up', 'eth' + test_int_num],
+                stderr=subprocess.STDOUT, encoding='utf-8')
 
         # fixed IPs, bogus IP
         port_info = {'mac_address': '123', 'fixed_ips': [
@@ -1314,9 +1327,10 @@ class TestServerTestCase(base.TestCase):
         # same as above but ifup fails
         port_info = {'mac_address': '123', 'fixed_ips': [
             {'ip_address': '10.0.0.5', 'subnet_cidr': '10.0.0.0/24'}]}
-        mock_check_output.side_effect = [subprocess.CalledProcessError(
-            7, 'test', RANDOM_ERROR), subprocess.CalledProcessError(
-            7, 'test', RANDOM_ERROR)]
+        mock_check_output.side_effect = [
+            subprocess.CalledProcessError(7, 'test', RANDOM_ERROR),
+            subprocess.CalledProcessError(7, 'test', RANDOM_ERROR)
+        ]
 
         m = self.useFixture(test_utils.OpenFixture(file_name)).mock_open
         with mock.patch('os.open'), mock.patch.object(os, 'fdopen', m):
@@ -1332,7 +1346,7 @@ class TestServerTestCase(base.TestCase):
                                           data=jsonutils.dumps(port_info))
             self.assertEqual(500, rv.status_code)
             self.assertEqual(
-                {'details': RANDOM_ERROR.decode('utf-8'),
+                {'details': RANDOM_ERROR,
                  'message': 'Error plugging network'},
                 jsonutils.loads(rv.data.decode('utf-8')))
 
@@ -1477,7 +1491,8 @@ class TestServerTestCase(base.TestCase):
 
             mock_check_output.assert_called_with(
                 ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                 'amphora-interface', 'up', 'eth3'], stderr=-2)
+                 'amphora-interface', 'up', 'eth3'], stderr=subprocess.STDOUT,
+                encoding='utf-8')
 
     def test_ubuntu_plug_VIP4(self):
         self._test_plug_VIP4(consts.UBUNTU)
@@ -1732,7 +1747,8 @@ class TestServerTestCase(base.TestCase):
             mock_check_output.assert_called_with(
                 ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
                  'amphora-interface', 'up',
-                 consts.NETNS_PRIMARY_INTERFACE], stderr=-2)
+                 consts.NETNS_PRIMARY_INTERFACE], stderr=subprocess.STDOUT,
+                encoding='utf-8')
 
         # One Interface down, Happy Path IPv4
         mode = stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP | stat.S_IROTH
@@ -1832,12 +1848,13 @@ class TestServerTestCase(base.TestCase):
             mock_check_output.assert_called_with(
                 ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
                  'amphora-interface', 'up',
-                 consts.NETNS_PRIMARY_INTERFACE], stderr=-2)
+                 consts.NETNS_PRIMARY_INTERFACE], stderr=subprocess.STDOUT,
+                encoding='utf-8')
 
         mock_check_output.side_effect = [
-            subprocess.CalledProcessError(
-                7, 'test', RANDOM_ERROR), subprocess.CalledProcessError(
-                7, 'test', RANDOM_ERROR)]
+            subprocess.CalledProcessError(7, 'test', RANDOM_ERROR),
+            subprocess.CalledProcessError(7, 'test', RANDOM_ERROR)
+        ]
 
         m = self.useFixture(test_utils.OpenFixture(file_name)).mock_open
         with mock.patch('os.open'), mock.patch.object(os, 'fdopen', m):
@@ -1853,7 +1870,7 @@ class TestServerTestCase(base.TestCase):
                                           data=jsonutils.dumps(subnet_info))
             self.assertEqual(500, rv.status_code)
             self.assertEqual(
-                {'details': RANDOM_ERROR.decode('utf-8'),
+                {'details': RANDOM_ERROR,
                  'message': 'Error plugging VIP'},
                 jsonutils.loads(rv.data.decode('utf-8')))
 
@@ -2086,9 +2103,14 @@ class TestServerTestCase(base.TestCase):
                 self, args[0], expected_dict)
 
             mock_check_output.assert_called_with(
-                ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
+                [
+                    'ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
                     'amphora-interface', 'up', '{netns_int}'.format(
-                        netns_int=consts.NETNS_PRIMARY_INTERFACE)], stderr=-2)
+                        netns_int=consts.NETNS_PRIMARY_INTERFACE
+                    )
+                ],
+                stderr=subprocess.STDOUT,
+                encoding='utf-8')
 
         # One Interface down, Happy Path IPv6
         flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC
@@ -2181,14 +2203,14 @@ class TestServerTestCase(base.TestCase):
             test_utils.assert_interface_files_equal(
                 self, args[0], expected_dict)
 
-            mock_check_output.assert_called_with(
-                ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                    'amphora-interface', 'up', '{netns_int}'.format(
-                        netns_int=consts.NETNS_PRIMARY_INTERFACE)], stderr=-2)
+            mock_check_output.assert_called_with([
+                'ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
+                'amphora-interface', 'up', consts.NETNS_PRIMARY_INTERFACE
+            ], stderr=subprocess.STDOUT, encoding='utf-8')
         mock_check_output.side_effect = [
-            subprocess.CalledProcessError(
-                7, 'test', RANDOM_ERROR), subprocess.CalledProcessError(
-                7, 'test', RANDOM_ERROR)]
+            subprocess.CalledProcessError(7, 'test', RANDOM_ERROR),
+            subprocess.CalledProcessError(7, 'test', RANDOM_ERROR)
+        ]
 
         m = self.useFixture(test_utils.OpenFixture(file_name)).mock_open
         with mock.patch('os.open'), mock.patch.object(os, 'fdopen', m):
@@ -2204,7 +2226,7 @@ class TestServerTestCase(base.TestCase):
                                           data=jsonutils.dumps(subnet_info))
             self.assertEqual(500, rv.status_code)
             self.assertEqual(
-                {'details': RANDOM_ERROR.decode('utf-8'),
+                {'details': RANDOM_ERROR,
                  'message': 'Error plugging VIP'},
                 jsonutils.loads(rv.data.decode('utf-8')))
 
@@ -2421,10 +2443,11 @@ class TestServerTestCase(base.TestCase):
             test_utils.assert_interface_files_equal(
                 self, args[0], expected_dict)
 
-            mock_check_output.assert_called_with(
-                ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                 'amphora-interface', 'up',
-                 consts.NETNS_PRIMARY_INTERFACE], stderr=-2)
+            mock_check_output.assert_called_with([
+                'ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
+                'amphora-interface', 'up',
+                consts.NETNS_PRIMARY_INTERFACE
+            ], stderr=subprocess.STDOUT, encoding='utf-8')
 
     def test_ubuntu_plug_VIP6_with_additional_VIP(self):
         self._test_plug_VIP6_with_additional_VIP(consts.UBUNTU)
@@ -2638,10 +2661,10 @@ class TestServerTestCase(base.TestCase):
             test_utils.assert_interface_files_equal(
                 self, args[0], expected_dict)
 
-            mock_check_output.assert_called_with(
-                ['ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
-                 'amphora-interface', 'up',
-                 consts.NETNS_PRIMARY_INTERFACE], stderr=-2)
+            mock_check_output.assert_called_with([
+                'ip', 'netns', 'exec', consts.AMPHORA_NAMESPACE,
+                'amphora-interface', 'up', consts.NETNS_PRIMARY_INTERFACE
+            ], stderr=subprocess.STDOUT, encoding='utf-8')
 
     def test_ubuntu_get_interface(self):
         self._test_get_interface(consts.UBUNTU)
diff --git a/octavia/tests/unit/amphorae/backends/agent/api_server/test_keepalived.py b/octavia/tests/unit/amphorae/backends/agent/api_server/test_keepalived.py
index 8f6c86a60f..af9cdc4b3b 100644
--- a/octavia/tests/unit/amphorae/backends/agent/api_server/test_keepalived.py
+++ b/octavia/tests/unit/amphorae/backends/agent/api_server/test_keepalived.py
@@ -35,7 +35,8 @@ class KeepalivedTestCase(base.TestCase):
         cmd = ("/usr/sbin/service octavia-keepalived {action}".format(
             action='start'))
         mock_check_output.assert_called_once_with(cmd.split(),
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         self.assertEqual(202, res.status_code)
 
         res = self.test_keepalived.manager_keepalived_service('restart')
diff --git a/octavia/tests/unit/amphorae/backends/agent/api_server/test_loadbalancer.py b/octavia/tests/unit/amphorae/backends/agent/api_server/test_loadbalancer.py
index 1adbbb3c15..afa7fc0b4b 100644
--- a/octavia/tests/unit/amphorae/backends/agent/api_server/test_loadbalancer.py
+++ b/octavia/tests/unit/amphorae/backends/agent/api_server/test_loadbalancer.py
@@ -86,7 +86,8 @@ class ListenerTestCase(base.TestCase):
             listener_id, consts.AMP_ACTION_START)
 
         mock_check_output.assert_called_once_with(ref_command_split,
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         mock_lb_exists.assert_called_once_with(listener_id)
         mock_vrrp_update.assert_not_called()
         self.assertEqual(202, result.status_code)
@@ -111,7 +112,8 @@ class ListenerTestCase(base.TestCase):
             listener_id, consts.AMP_ACTION_RELOAD)
 
         mock_check_output.assert_called_once_with(ref_command_split,
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         mock_lb_exists.assert_called_once_with(listener_id)
         mock_vrrp_update.assert_called_once_with(listener_id,
                                                  consts.AMP_ACTION_RELOAD)
@@ -134,7 +136,8 @@ class ListenerTestCase(base.TestCase):
             listener_id, consts.AMP_ACTION_RELOAD)
 
         mock_check_output.assert_called_once_with(ref_command_split,
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         mock_lb_exists.assert_called_once_with(listener_id)
         mock_vrrp_update.assert_called_once_with(listener_id,
                                                  consts.AMP_ACTION_RELOAD)
@@ -157,13 +160,14 @@ class ListenerTestCase(base.TestCase):
         ref_command_split.append(consts.AMP_ACTION_START)
 
         mock_check_output.side_effect = subprocess.CalledProcessError(
-            output=b'bogus', returncode=-2, cmd='sit')
+            output='bogus', returncode=-2, cmd='sit')
 
         result = self.test_loadbalancer.start_stop_lb(
             listener_id, consts.AMP_ACTION_START)
 
         mock_check_output.assert_called_once_with(ref_command_split,
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         mock_lb_exists.assert_called_once_with(listener_id)
         mock_vrrp_update.assert_not_called()
         self.assertEqual(500, result.status_code)
@@ -181,13 +185,14 @@ class ListenerTestCase(base.TestCase):
         ref_command_split.append(consts.AMP_ACTION_START)
 
         mock_check_output.side_effect = subprocess.CalledProcessError(
-            output=b'Job is already running', returncode=-2, cmd='sit')
+            output='Job is already running', returncode=-2, cmd='sit')
 
         result = self.test_loadbalancer.start_stop_lb(
             listener_id, consts.AMP_ACTION_START)
 
         mock_check_output.assert_called_once_with(ref_command_split,
-                                                  stderr=subprocess.STDOUT)
+                                                  stderr=subprocess.STDOUT,
+                                                  encoding='utf-8')
         mock_lb_exists.assert_called_once_with(listener_id)
         mock_vrrp_update.assert_not_called()
         self.assertEqual(202, result.status_code)
@@ -220,7 +225,7 @@ class ListenerTestCase(base.TestCase):
 
         mock_check_output.side_effect = [
             subprocess.CalledProcessError(
-                output=b'haproxy.service is not active, cannot reload.',
+                output='haproxy.service is not active, cannot reload.',
                 returncode=-2, cmd='service'),
             None]
         mock_check_status.return_value = 'ACTIVE'
@@ -248,13 +253,13 @@ class ListenerTestCase(base.TestCase):
 
         mock_check_output.side_effect = [
             subprocess.CalledProcessError(
-                output=b'haproxy.service is not active, cannot reload.',
+                output='haproxy.service is not active, cannot reload.',
                 returncode=-2, cmd='service'),
             subprocess.CalledProcessError(
-                output=b'haproxy.service is not active, cannot reload.',
+                output='haproxy.service is not active, cannot reload.',
                 returncode=-2, cmd='service'),
             subprocess.CalledProcessError(
-                output=b'haproxy.service is not active, cannot reload.',
+                output='haproxy.service is not active, cannot reload.',
                 returncode=-2, cmd='service')]
         mock_check_status.return_value = 'ACTIVE'
         mock_check_status.side_effect = None
diff --git a/octavia/tests/unit/amphorae/backends/agent/api_server/test_util.py b/octavia/tests/unit/amphorae/backends/agent/api_server/test_util.py
index 551f4d06fb..150cd1a3f6 100644
--- a/octavia/tests/unit/amphorae/backends/agent/api_server/test_util.py
+++ b/octavia/tests/unit/amphorae/backends/agent/api_server/test_util.py
@@ -162,7 +162,8 @@ class TestUtil(base.TestCase):
 
         util.run_systemctl_command('test', 'world')
         mock_check_output.assert_called_once_with(
-            ['systemctl', 'test', 'world'], stderr=subprocess.STDOUT)
+            ['systemctl', 'test', 'world'], stderr=subprocess.STDOUT,
+            encoding='utf-8')
 
         mock_check_output.side_effect = subprocess.CalledProcessError(1,
                                                                       'boom')
diff --git a/octavia/tests/unit/amphorae/backends/health_daemon/test_health_daemon.py b/octavia/tests/unit/amphorae/backends/health_daemon/test_health_daemon.py
index e7af2aea20..8397c16a9d 100644
--- a/octavia/tests/unit/amphorae/backends/health_daemon/test_health_daemon.py
+++ b/octavia/tests/unit/amphorae/backends/health_daemon/test_health_daemon.py
@@ -12,6 +12,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 #
+import json
 import os
 import queue
 from unittest import mock
@@ -19,7 +20,6 @@ from unittest import mock
 from oslo_config import cfg
 from oslo_config import fixture as oslo_fixture
 from oslo_utils import uuidutils
-import simplejson
 
 from octavia.amphorae.backends.health_daemon import health_daemon
 from octavia.common import constants
@@ -345,7 +345,7 @@ class TestHealthDaemon(base.TestCase):
 
         with mock.patch('os.open'), mock.patch.object(
                 os, 'fdopen', self.mock_open) as mock_fdopen:
-            mock_fdopen().read.return_value = simplejson.dumps({
+            mock_fdopen().read.return_value = json.dumps({
                 LISTENER_ID1: {'bin': 1, 'bout': 2},
             })
             msg = health_daemon.build_stats_message()
@@ -353,7 +353,7 @@ class TestHealthDaemon(base.TestCase):
         self.assertEqual(SAMPLE_STATS_MSG, msg)
 
         mock_get_stats.assert_any_call(lb1_stats_socket)
-        mock_fdopen().write.assert_called_once_with(simplejson.dumps({
+        mock_fdopen().write.assert_called_once_with(json.dumps({
             LISTENER_ID1: {
                 'bin': int(FRONTEND_STATS['bin']),
                 'bout': int(FRONTEND_STATS['bout']),
@@ -450,14 +450,14 @@ class TestHealthDaemon(base.TestCase):
 
         with mock.patch('os.open'), mock.patch.object(
                 os, 'fdopen', self.mock_open) as mock_fdopen:
-            mock_fdopen().read.return_value = simplejson.dumps({
+            mock_fdopen().read.return_value = json.dumps({
                 udp_listener_id1: {
                     'bin': 1, 'bout': 2, "ereq": 0, "stot": 0}
             })
             msg = health_daemon.build_stats_message()
 
         self.assertEqual(expected, msg)
-        mock_fdopen().write.assert_called_once_with(simplejson.dumps({
+        mock_fdopen().write.assert_called_once_with(json.dumps({
             udp_listener_id1: {'bin': 5, 'bout': 10, 'ereq': 0, 'stot': 5},
             udp_listener_id3: {'bin': 0, 'bout': 0, 'ereq': 0, 'stot': 0},
         }))
@@ -480,7 +480,7 @@ class TestHealthDaemon(base.TestCase):
 
         with mock.patch('os.open'), mock.patch.object(
                 os, 'fdopen', self.mock_open) as mock_fdopen:
-            mock_fdopen().read.return_value = simplejson.dumps({
+            mock_fdopen().read.return_value = json.dumps({
                 LISTENER_ID1: {'bin': 15, 'bout': 20},
             })
             msg = health_daemon.build_stats_message()
@@ -488,7 +488,7 @@ class TestHealthDaemon(base.TestCase):
         self.assertEqual(SAMPLE_MSG_HAPROXY_RESTART, msg)
 
         mock_get_stats.assert_any_call(lb1_stats_socket)
-        mock_fdopen().write.assert_called_once_with(simplejson.dumps({
+        mock_fdopen().write.assert_called_once_with(json.dumps({
             LISTENER_ID1: {
                 'bin': int(FRONTEND_STATS['bin']),
                 'bout': int(FRONTEND_STATS['bout']),
diff --git a/octavia/tests/unit/amphorae/backends/utils/test_interface.py b/octavia/tests/unit/amphorae/backends/utils/test_interface.py
index 24753e7216..18c6bd1c4b 100644
--- a/octavia/tests/unit/amphorae/backends/utils/test_interface.py
+++ b/octavia/tests/unit/amphorae/backends/utils/test_interface.py
@@ -278,7 +278,7 @@ class TestInterface(base.TestCase):
                  iface),
              "-pf",
              f"/run/dhclient-{iface}.pid",
-             iface], stderr=-2)
+             iface], stderr=subprocess.STDOUT)
 
     @mock.patch('subprocess.check_output')
     def test__dhclient_down(self, mock_check_output):
@@ -295,7 +295,7 @@ class TestInterface(base.TestCase):
                  iface),
              "-pf",
              f"/run/dhclient-{iface}.pid",
-             iface], stderr=-2)
+             iface], stderr=subprocess.STDOUT)
 
     @mock.patch('subprocess.check_output')
     def test__ipv6auto_up(self, mock_check_output):
@@ -306,9 +306,11 @@ class TestInterface(base.TestCase):
 
         mock_check_output.assert_has_calls([
             mock.call(["/sbin/sysctl", "-w",
-                       "net.ipv6.conf.iface2.accept_ra=2"], stderr=-2),
+                       "net.ipv6.conf.iface2.accept_ra=2"],
+                      stderr=subprocess.STDOUT),
             mock.call(["/sbin/sysctl", "-w",
-                       "net.ipv6.conf.iface2.autoconf=1"], stderr=-2)])
+                       "net.ipv6.conf.iface2.autoconf=1"],
+                      stderr=subprocess.STDOUT)])
 
     @mock.patch('subprocess.check_output')
     def test__ipv6auto_down(self, mock_check_output):
@@ -319,9 +321,11 @@ class TestInterface(base.TestCase):
 
         mock_check_output.assert_has_calls([
             mock.call(["/sbin/sysctl", "-w",
-                       "net.ipv6.conf.iface2.accept_ra=0"], stderr=-2),
+                       "net.ipv6.conf.iface2.accept_ra=0"],
+                      stderr=subprocess.STDOUT),
             mock.call(["/sbin/sysctl", "-w",
-                       "net.ipv6.conf.iface2.autoconf=0"], stderr=-2)])
+                       "net.ipv6.conf.iface2.autoconf=0"],
+                      stderr=subprocess.STDOUT)])
 
     @mock.patch('pyroute2.IPRoute.rule')
     @mock.patch('pyroute2.IPRoute.route')
@@ -579,15 +583,16 @@ class TestInterface(base.TestCase):
 
         mock_check_output.assert_has_calls([
             mock.call([consts.NFT_CMD, consts.NFT_ADD, 'table',
-                       consts.NFT_FAMILY, consts.NFT_VIP_TABLE], stderr=-2),
+                       consts.NFT_FAMILY, consts.NFT_VIP_TABLE],
+                      stderr=subprocess.STDOUT),
             mock.call([consts.NFT_CMD, consts.NFT_ADD, 'chain',
                        consts.NFT_FAMILY, consts.NFT_VIP_TABLE,
                        consts.NFT_VIP_CHAIN, '{', 'type', 'filter', 'hook',
                        'ingress', 'device', 'fake-eth1', 'priority',
                        consts.NFT_SRIOV_PRIORITY, ';', 'policy', 'drop', ';',
-                       '}'], stderr=-2),
+                       '}'], stderr=subprocess.STDOUT),
             mock.call([consts.NFT_CMD, '-o', '-f', consts.NFT_VIP_RULES_FILE],
-                      stderr=-2),
+                      stderr=subprocess.STDOUT),
             mock.call(["post-up", "fake-eth1"])
         ])
 
@@ -925,13 +930,13 @@ class TestInterface(base.TestCase):
                            iface.name),
                        "-pf",
                        f"/run/dhclient-{iface.name}.pid",
-                       iface.name], stderr=-2),
+                       iface.name], stderr=subprocess.STDOUT),
             mock.call(["/sbin/sysctl", "-w",
                        f"net.ipv6.conf.{iface.name}.accept_ra=2"],
-                      stderr=-2),
+                      stderr=subprocess.STDOUT),
             mock.call(["/sbin/sysctl", "-w",
                        f"net.ipv6.conf.{iface.name}.autoconf=1"],
-                      stderr=-2),
+                      stderr=subprocess.STDOUT),
             mock.call(["post-up", iface.name])
         ])
 
@@ -1342,13 +1347,13 @@ class TestInterface(base.TestCase):
                            iface.name),
                        "-pf",
                        f"/run/dhclient-{iface.name}.pid",
-                       iface.name], stderr=-2),
+                       iface.name], stderr=subprocess.STDOUT),
             mock.call(["/sbin/sysctl", "-w",
                        f"net.ipv6.conf.{iface.name}.accept_ra=0"],
-                      stderr=-2),
+                      stderr=subprocess.STDOUT),
             mock.call(["/sbin/sysctl", "-w",
                        f"net.ipv6.conf.{iface.name}.autoconf=0"],
-                      stderr=-2),
+                      stderr=subprocess.STDOUT),
             mock.call(["post-down", iface.name])
         ])
 
diff --git a/requirements.txt b/requirements.txt
index d3acbd82d8..66020e6418 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -46,7 +46,6 @@ tenacity>=5.0.4  # Apache-2.0
 distro>=1.2.0 # Apache-2.0
 jsonschema>=3.2.0 # MIT
 octavia-lib>=3.3.0 # Apache-2.0
-simplejson>=3.13.2 # MIT
 setproctitle>=1.1.10 # BSD
 python-dateutil>=2.7.0 # BSD