diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 85377edb..2399c1d4 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -28,3 +28,8 @@ repos:
     hooks:
       - id: bandit
         args: ['-x', 'tests']
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v3.18.0
+    hooks:
+      - id: pyupgrade
+        args: [--py3-only]
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 975740fb..8e6f151c 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Copyright (C) 2020 Red Hat, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
diff --git a/oslo_config/cfg.py b/oslo_config/cfg.py
index 672eaa0a..58982616 100644
--- a/oslo_config/cfg.py
+++ b/oslo_config/cfg.py
@@ -106,7 +106,8 @@ class NoSuchOptError(Error, AttributeError):
 
     def __str__(self):
         group_name = 'DEFAULT' if self.group is None else self.group.name
-        return "no such option %s in group [%s]" % (self.opt_name, group_name)
+        return "no such option {} in group [{}]".format(
+            self.opt_name, group_name)
 
 
 class NoSuchGroupError(Error):
@@ -138,8 +139,8 @@ class RequiredOptError(Error):
 
     def __str__(self):
         group_name = 'DEFAULT' if self.group is None else self.group.name
-        return "value required for option %s in group [%s]" % (self.opt_name,
-                                                               group_name)
+        return "value required for option {} in group [{}]".format(
+            self.opt_name, group_name)
 
 
 class TemplateSubstitutionError(Error):
@@ -189,7 +190,7 @@ class ConfigFileParseError(Error):
         self.msg = msg
 
     def __str__(self):
-        return 'Failed to parse %s: %s' % (self.config_file, self.msg)
+        return 'Failed to parse {}: {}'.format(self.config_file, self.msg)
 
 
 class ConfigSourceValueError(Error, ValueError):
@@ -260,7 +261,7 @@ def _search_dirs(dirs, basename, extension=""):
     :returns: the path to a matching file or directory, or None
     """
     for d in dirs:
-        path = os.path.join(d, '%s%s' % (basename, extension))
+        path = os.path.join(d, '{}{}'.format(basename, extension))
         if os.path.exists(path):
             return path
 
@@ -538,7 +539,7 @@ class Opt:
                  deprecated_for_removal=False, deprecated_reason=None,
                  deprecated_since=None, mutable=False, advanced=False):
         if name.startswith('_'):
-            raise ValueError('illegal name %s with prefix _' % (name,))
+            raise ValueError('illegal name {} with prefix _'.format(name))
         self.name = name
 
         if type is None:
@@ -917,14 +918,14 @@ class StrOpt(Opt):
 
     def __init__(self, name, choices=None, quotes=None,
                  regex=None, ignore_case=False, max_length=None, **kwargs):
-        super(StrOpt, self).__init__(name,
-                                     type=types.String(
-                                         choices=choices,
-                                         quotes=quotes,
-                                         regex=regex,
-                                         ignore_case=ignore_case,
-                                         max_length=max_length),
-                                     **kwargs)
+        super().__init__(name,
+                         type=types.String(
+                             choices=choices,
+                             quotes=quotes,
+                             regex=regex,
+                             ignore_case=ignore_case,
+                             max_length=max_length),
+                         **kwargs)
 
     def _get_choice_text(self, choice):
         if choice is None:
@@ -935,7 +936,7 @@ class StrOpt(Opt):
 
     def _get_argparse_kwargs(self, group, **kwargs):
         """Extends the base argparse keyword dict for the config dir option."""
-        kwargs = super(StrOpt, self)._get_argparse_kwargs(group)
+        kwargs = super()._get_argparse_kwargs(group)
 
         if getattr(self.type, 'choices', None):
             choices_text = ', '.join([self._get_choice_text(choice)
@@ -965,11 +966,11 @@ class BoolOpt(Opt):
     def __init__(self, name, **kwargs):
         if 'positional' in kwargs:
             raise ValueError('positional boolean args not supported')
-        super(BoolOpt, self).__init__(name, type=types.Boolean(), **kwargs)
+        super().__init__(name, type=types.Boolean(), **kwargs)
 
     def _add_to_cli(self, parser, group=None):
         """Extends the base class method to add the --nooptname option."""
-        super(BoolOpt, self)._add_to_cli(parser, group)
+        super()._add_to_cli(parser, group)
         self._add_inverse_to_argparse(parser, group)
 
     def _add_inverse_to_argparse(self, parser, group):
@@ -991,7 +992,7 @@ class BoolOpt(Opt):
     def _get_argparse_kwargs(self, group, action='store_true', **kwargs):
         """Extends the base argparse keyword dict for boolean options."""
 
-        kwargs = super(BoolOpt, self)._get_argparse_kwargs(group, **kwargs)
+        kwargs = super()._get_argparse_kwargs(group, **kwargs)
         # type has no effect for BoolOpt, it only matters for
         # values that came from config files
         if 'type' in kwargs:
@@ -1030,12 +1031,12 @@ class IntOpt(Opt):
     """
 
     def __init__(self, name, min=None, max=None, choices=None, **kwargs):
-        super(IntOpt, self).__init__(name,
-                                     type=types.Integer(
-                                         min=min,
-                                         max=max,
-                                         choices=choices),
-                                     **kwargs)
+        super().__init__(name,
+                         type=types.Integer(
+                             min=min,
+                             max=max,
+                             choices=choices),
+                         **kwargs)
 
 
 class FloatOpt(Opt):
@@ -1055,8 +1056,7 @@ class FloatOpt(Opt):
     """
 
     def __init__(self, name, min=None, max=None, **kwargs):
-        super(FloatOpt, self).__init__(name, type=types.Float(min, max),
-                                       **kwargs)
+        super().__init__(name, type=types.Float(min, max), **kwargs)
 
 
 class ListOpt(Opt):
@@ -1075,10 +1075,10 @@ class ListOpt(Opt):
     """
 
     def __init__(self, name, item_type=None, bounds=None, **kwargs):
-        super(ListOpt, self).__init__(name,
-                                      type=types.List(item_type=item_type,
-                                                      bounds=bounds),
-                                      **kwargs)
+        super().__init__(name,
+                         type=types.List(item_type=item_type,
+                                         bounds=bounds),
+                         **kwargs)
 
 
 class DictOpt(Opt):
@@ -1094,7 +1094,7 @@ class DictOpt(Opt):
     """
 
     def __init__(self, name, **kwargs):
-        super(DictOpt, self).__init__(name, type=types.Dict(), **kwargs)
+        super().__init__(name, type=types.Dict(), **kwargs)
 
 
 class IPOpt(Opt):
@@ -1112,8 +1112,8 @@ class IPOpt(Opt):
     """
 
     def __init__(self, name, version=None, **kwargs):
-        super(IPOpt, self).__init__(name, type=types.IPAddress(version),
-                                    **kwargs)
+        super().__init__(name, type=types.IPAddress(version),
+                         **kwargs)
 
 
 class PortOpt(Opt):
@@ -1144,7 +1144,7 @@ class PortOpt(Opt):
     def __init__(self, name, min=None, max=None, choices=None, **kwargs):
         type = types.Port(min=min, max=max, choices=choices,
                           type_name='port value')
-        super(PortOpt, self).__init__(name, type=type, **kwargs)
+        super().__init__(name, type=type, **kwargs)
 
 
 class HostnameOpt(Opt):
@@ -1160,8 +1160,8 @@ class HostnameOpt(Opt):
     """
 
     def __init__(self, name, **kwargs):
-        super(HostnameOpt, self).__init__(name, type=types.Hostname(),
-                                          **kwargs)
+        super().__init__(name, type=types.Hostname(),
+                         **kwargs)
 
 
 class HostAddressOpt(Opt):
@@ -1181,9 +1181,9 @@ class HostAddressOpt(Opt):
     """
 
     def __init__(self, name, version=None, **kwargs):
-        super(HostAddressOpt, self).__init__(name,
-                                             type=types.HostAddress(version),
-                                             **kwargs)
+        super().__init__(name,
+                         type=types.HostAddress(version),
+                         **kwargs)
 
 
 class HostDomainOpt(Opt):
@@ -1203,9 +1203,9 @@ class HostDomainOpt(Opt):
     """
 
     def __init__(self, name, version=None, **kwargs):
-        super(HostDomainOpt, self).__init__(name,
-                                            type=types.HostDomain(version),
-                                            **kwargs)
+        super().__init__(name,
+                         type=types.HostDomain(version),
+                         **kwargs)
 
 
 class URIOpt(Opt):
@@ -1230,7 +1230,7 @@ class URIOpt(Opt):
 
     def __init__(self, name, max_length=None, schemes=None, **kwargs):
         type = types.URI(max_length=max_length, schemes=schemes)
-        super(URIOpt, self).__init__(name, type=type, **kwargs)
+        super().__init__(name, type=type, **kwargs)
 
 
 class MultiOpt(Opt):
@@ -1259,11 +1259,11 @@ class MultiOpt(Opt):
     multi = True
 
     def __init__(self, name, item_type, **kwargs):
-        super(MultiOpt, self).__init__(name, item_type, **kwargs)
+        super().__init__(name, item_type, **kwargs)
 
     def _get_argparse_kwargs(self, group, **kwargs):
         """Extends the base argparse keyword dict for multi value options."""
-        kwargs = super(MultiOpt, self)._get_argparse_kwargs(group)
+        kwargs = super()._get_argparse_kwargs(group)
         if not self.positional:
             kwargs['action'] = 'append'
         else:
@@ -1283,9 +1283,9 @@ class MultiStrOpt(MultiOpt):
     """
 
     def __init__(self, name, **kwargs):
-        super(MultiStrOpt, self).__init__(name,
-                                          item_type=types.MultiString(),
-                                          **kwargs)
+        super().__init__(name,
+                         item_type=types.MultiString(),
+                         **kwargs)
 
 
 class SubCommandOpt(Opt):
@@ -1321,8 +1321,8 @@ class SubCommandOpt(Opt):
         this subparsers object can be used to register parsers for
         sub-commands.
         """
-        super(SubCommandOpt, self).__init__(name, type=types.String(),
-                                            dest=dest, help=help)
+        super().__init__(name, type=types.String(),
+                         dest=dest, help=help)
         self.handler = handler
         self.title = title
         self.description = description
@@ -1384,11 +1384,11 @@ class _ConfigFileOpt(Opt):
             ConfigParser._parse_file(values, namespace)
 
     def __init__(self, name, **kwargs):
-        super(_ConfigFileOpt, self).__init__(name, lambda x: x, **kwargs)
+        super().__init__(name, lambda x: x, **kwargs)
 
     def _get_argparse_kwargs(self, group, **kwargs):
         """Extends the base argparse keyword dict for the config file opt."""
-        kwargs = super(_ConfigFileOpt, self)._get_argparse_kwargs(group)
+        kwargs = super()._get_argparse_kwargs(group)
         kwargs['action'] = self.ConfigFileAction
         return kwargs
 
@@ -1439,12 +1439,12 @@ class _ConfigDirOpt(Opt):
                 ConfigParser._parse_file(config_file, namespace)
 
     def __init__(self, name, **kwargs):
-        super(_ConfigDirOpt, self).__init__(name, type=types.List(),
-                                            **kwargs)
+        super().__init__(name, type=types.List(),
+                         **kwargs)
 
     def _get_argparse_kwargs(self, group, **kwargs):
         """Extends the base argparse keyword dict for the config dir option."""
-        kwargs = super(_ConfigDirOpt, self)._get_argparse_kwargs(group)
+        kwargs = super()._get_argparse_kwargs(group)
         kwargs['action'] = self.ConfigDirAction
         return kwargs
 
@@ -1559,7 +1559,7 @@ class OptGroup:
 
 class ParseError(iniparser.ParseError):
     def __init__(self, msg, lineno, line, filename):
-        super(ParseError, self).__init__(msg, lineno, line)
+        super().__init__(msg, lineno, line)
         self.filename = filename
 
     def __str__(self):
@@ -1578,7 +1578,7 @@ class ConfigParser(iniparser.BaseParser):
     """
 
     def __init__(self, filename, sections):
-        super(ConfigParser, self).__init__()
+        super().__init__()
         self.filename = filename
         self.sections = sections
         self._normalized = None
@@ -1589,7 +1589,7 @@ class ConfigParser(iniparser.BaseParser):
 
     def parse(self):
         with open(self.filename) as f:
-            return super(ConfigParser, self).parse(f.readlines())
+            return super().parse(f.readlines())
 
     def new_section(self, section):
         self.section = section
@@ -1637,7 +1637,7 @@ class ConfigParser(iniparser.BaseParser):
             parser.parse()
         except iniparser.ParseError as pe:
             raise ConfigFileParseError(pe.filename, str(pe))
-        except IOError as err:
+        except OSError as err:
             if err.errno == errno.ENOENT:
                 namespace._file_not_found(config_file)
                 return
@@ -1892,8 +1892,7 @@ class _Namespace(argparse.Namespace):
 
     def _sections(self):
         for sections in self._parsed:
-            for section in sections:
-                yield section
+            yield from sections
 
 
 class _CachedArgumentParser(argparse.ArgumentParser):
@@ -1908,7 +1907,7 @@ class _CachedArgumentParser(argparse.ArgumentParser):
     """
 
     def __init__(self, prog=None, usage=None, **kwargs):
-        super(_CachedArgumentParser, self).__init__(prog, usage, **kwargs)
+        super().__init__(prog, usage, **kwargs)
         self._args_cache = {}
 
     def add_parser_argument(self, container, *args, **kwargs):
@@ -1944,15 +1943,15 @@ class _CachedArgumentParser(argparse.ArgumentParser):
 
     def parse_args(self, args=None, namespace=None):
         self.initialize_parser_arguments()
-        return super(_CachedArgumentParser, self).parse_args(args, namespace)
+        return super().parse_args(args, namespace)
 
     def print_help(self, file=None):
         self.initialize_parser_arguments()
-        super(_CachedArgumentParser, self).print_help(file)
+        super().print_help(file)
 
     def print_usage(self, file=None):
         self.initialize_parser_arguments()
-        super(_CachedArgumentParser, self).print_usage(file)
+        super().print_usage(file)
 
 
 class ConfigOpts(abc.Mapping):
@@ -2000,7 +1999,7 @@ class ConfigOpts(abc.Mapping):
         self._oparser = None
         self._namespace = None
         self._mutable_ns = None
-        self._mutate_hooks = set([])
+        self._mutate_hooks = set()
         self.__cache = {}
         self.__drivers_cache = {}
         self._config_opts = []
@@ -2305,7 +2304,7 @@ class ConfigOpts(abc.Mapping):
             b_opts_sub += f"[{k}]='{sub}' "
         b_map = ' '.join([f"[{k}]={v}" for k, v in maps.items()])
         b_multi = ' '.join([f"[{k}]=true" for k in multi])
-        with open(template, "r") as input:
+        with open(template) as input:
             output = input.read().format(scriptname=self.prog,
                                          opts=b_opts,
                                          opts_sub=b_opts_sub,
@@ -2372,7 +2371,7 @@ class ConfigOpts(abc.Mapping):
                     desc = descr[k+'_'+ik] if descr[k+'_'+ik] else ''
                     c_opts += f"'[{desc}]' \\\n"
                 c_opts += f"\n{t*4};;\n"
-        with open(template, "r") as input:
+        with open(template) as input:
             output = input.read().format(scriptname=p,
                                          opts=z_opts,
                                          commands_list=c_list,
@@ -2449,9 +2448,8 @@ class ConfigOpts(abc.Mapping):
 
     def __iter__(self):
         """Iterate over all registered opt and group names."""
-        for key in itertools.chain(list(self._opts.keys()),
-                                   list(self._groups.keys())):
-            yield key
+        yield from itertools.chain(list(self._opts.keys()),
+                                   list(self._groups.keys()))
 
     def __len__(self):
         """Return the number of options and option groups."""
@@ -2824,7 +2822,7 @@ class ConfigOpts(abc.Mapping):
             for opt_name in sorted(self._groups[group_name]._opts):
                 opt = self._get_opt_info(opt_name, group_name)['opt']
                 logger.log(lvl, "%-30s = %s",
-                           "%s.%s" % (group_name, opt_name),
+                           "{}.{}".format(group_name, opt_name),
                            _sanitize(opt, getattr(group_attr, opt_name)))
 
         logger.log(lvl, "*" * 80)
@@ -2941,8 +2939,8 @@ class ConfigOpts(abc.Mapping):
                     if env_val[0] != sources._NoValue:
                         return (convert(env_val[0]), env_val[1])
             except ValueError as ve:
-                message = "Value for option %s from %s is not valid: %s" % (
-                    opt.name, alt_loc, str(ve))
+                message = ("Value for option {} from {} is not valid: {}"
+                           .format(opt.name, alt_loc, str(ve)))
                 # Preserve backwards compatibility for file-based value
                 # errors.
                 if alt_loc.location == Locations.user:
@@ -3194,8 +3192,9 @@ class ConfigOpts(abc.Mapping):
             try:
                 self._convert_value(value, opt)
             except ValueError:
-                sys.stderr.write("argument --%s: Invalid %s value: %s\n" % (
-                    opt.dest, repr(opt.type), value))
+                sys.stderr.write(
+                    "argument --{}: Invalid {} value: {}\n".format(
+                        opt.dest, repr(opt.type), value))
                 raise SystemExit(1)
 
     def _reload_config_files(self):
@@ -3330,7 +3329,7 @@ class ConfigOpts(abc.Mapping):
         Returns a sorted list of all section names found in the
         configuration files, whether declared beforehand or not.
         """
-        s = set([])
+        s = set()
         if self._mutable_ns:
             s |= set(self._mutable_ns._sections())
         if self._namespace:
@@ -3387,8 +3386,7 @@ class ConfigOpts(abc.Mapping):
 
         def __iter__(self):
             """Iterate over all registered opt and group names."""
-            for key in self._group._opts.keys():
-                yield key
+            yield from self._group._opts.keys()
 
         def __len__(self):
             """Return the number of options and option groups."""
diff --git a/oslo_config/fixture.py b/oslo_config/fixture.py
index 2cb4662c..6a555fa8 100644
--- a/oslo_config/fixture.py
+++ b/oslo_config/fixture.py
@@ -31,7 +31,7 @@ class Config(fixtures.Fixture):
         self.conf = conf
 
     def setUp(self):
-        super(Config, self).setUp()
+        super().setUp()
         # NOTE(morganfainberg): unregister must be added to cleanup before
         # reset is because cleanup works in reverse order of registered items,
         # and a reset must occur before unregistering options can occur.
diff --git a/oslo_config/generator.py b/oslo_config/generator.py
index 8f8f85e5..f5af92a1 100644
--- a/oslo_config/generator.py
+++ b/oslo_config/generator.py
@@ -284,7 +284,7 @@ class _OptFormatter:
             else:
                 opt_help = opt.help
 
-            help_text = '%s%s (%s)' % (opt_prefix, opt_help, opt_type)
+            help_text = '{}{} ({})'.format(opt_prefix, opt_help, opt_type)
         else:
             help_text = '(%s)' % opt_type
         lines = self._format_help(help_text)
@@ -298,7 +298,7 @@ class _OptFormatter:
         if getattr(opt.type, 'choices', None):
             lines.append('# Possible values:\n')
             for choice in opt.type.choices:
-                help_text = '%s - %s' % (
+                help_text = '{} - {}'.format(
                     self._get_choice_text(choice),
                     opt.type.choices[choice] or '<No description provided>')
                 lines.extend(self._format_help(help_text))
@@ -379,9 +379,9 @@ class _OptFormatter:
             if default_str:
                 default_str = ' ' + default_str.replace('\n', '\n#    ')
             if self.minimal:
-                lines.append('%s =%s\n' % (opt.dest, default_str))
+                lines.append('{} ={}\n'.format(opt.dest, default_str))
             else:
-                lines.append('#%s =%s\n' % (opt.dest, default_str))
+                lines.append('#{} ={}\n'.format(opt.dest, default_str))
 
         self.writelines(lines)
 
@@ -578,7 +578,7 @@ def _output_opts(f, group, group_data):
             except Exception as err:
                 f.write('# Warning: Failed to format sample for %s\n' %
                         (opt.dest,))
-                f.write('# %s\n' % (err,))
+                f.write('# {}\n'.format(err))
 
 
 def _get_groups(conf_ns):
diff --git a/oslo_config/sphinxconfiggen.py b/oslo_config/sphinxconfiggen.py
index 616e8573..3ff5028f 100644
--- a/oslo_config/sphinxconfiggen.py
+++ b/oslo_config/sphinxconfiggen.py
@@ -56,7 +56,7 @@ def _get_default_basename(config_file):
 def _generate_sample(app, config_file, base_name):
 
     def info(msg):
-        LOG.info('[%s] %s' % (__name__, msg))
+        LOG.info('[{}] {}'.format(__name__, msg))
 
     # If we are given a file that isn't an absolute path, look for it
     # in the source directory if it doesn't exist.
diff --git a/oslo_config/sphinxext.py b/oslo_config/sphinxext.py
index 6aadf73c..524486f5 100644
--- a/oslo_config/sphinxext.py
+++ b/oslo_config/sphinxext.py
@@ -60,8 +60,8 @@ def _indent(text, n=2):
 def _make_anchor_target(group_name, option_name):
     # We need to ensure this is unique across entire documentation
     # http://www.sphinx-doc.org/en/stable/markup/inline.html#ref-role
-    target = '%s.%s' % (cfg._normalize_group_name(group_name),
-                        option_name.lower())
+    target = '{}.{}'.format(cfg._normalize_group_name(group_name),
+                            option_name.lower())
     return target
 
 
@@ -220,12 +220,10 @@ def _format_group_opts(namespace, group_name, group_obj, opt_list):
     group_name = group_name or 'DEFAULT'
     LOG.debug('%s %s', namespace, group_name)
 
-    for line in _format_group(namespace, group_name, group_obj):
-        yield line
+    yield from _format_group(namespace, group_name, group_obj)
 
     for opt in opt_list:
-        for line in _format_opt(opt, group_name):
-            yield line
+        yield from _format_opt(opt, group_name)
 
 
 def _format_option_help(namespaces, split_namespaces):
@@ -252,8 +250,7 @@ def _format_option_help(namespaces, split_namespaces):
                     group_obj=group,
                     opt_list=opts,
                 )
-                for line in lines:
-                    yield line
+                yield from lines
     else:
         # Merge the options from different namespaces that belong to
         # the same group together and format them without the
@@ -278,8 +275,7 @@ def _format_option_help(namespaces, split_namespaces):
                 group_obj=group_objs.get(group_name),
                 opt_list=group_opts,
             )
-            for line in lines:
-                yield line
+            yield from lines
 
 
 class ShowOptionsDirective(rst.Directive):
@@ -337,7 +333,7 @@ class ConfigGroupXRefRole(XRefRole):
     "Handles :oslo.config:group: roles pointing to configuration groups."
 
     def __init__(self):
-        super(ConfigGroupXRefRole, self).__init__(
+        super().__init__(
             warn_dangling=True,
         )
 
@@ -350,7 +346,7 @@ class ConfigOptXRefRole(XRefRole):
     "Handles :oslo.config:option: roles pointing to configuration options."
 
     def __init__(self):
-        super(ConfigOptXRefRole, self).__init__(
+        super().__init__(
             warn_dangling=True,
         )
 
@@ -400,7 +396,7 @@ class ConfigGroup(rst.Directive):
             result.append(text, source_name)
 
         if namespace:
-            title = '%s: %s' % (namespace, group_name)
+            title = '{}: {}'.format(namespace, group_name)
         else:
             title = group_name
 
diff --git a/oslo_config/tests/test_cfg.py b/oslo_config/tests/test_cfg.py
index 383b70f1..d1e4f25e 100644
--- a/oslo_config/tests/test_cfg.py
+++ b/oslo_config/tests/test_cfg.py
@@ -108,7 +108,7 @@ class BaseTestCase(base.BaseTestCase):
                 validate_default_values=True)
 
     def setUp(self):
-        super(BaseTestCase, self).setUp()
+        super().setUp()
         self.useFixture(fixtures.NestedTempfile())
         self.conf = self.TestConfigOpts()
 
@@ -1130,7 +1130,7 @@ def _fake_deprecated_feature(logger, msg, *args, **kwargs):
 class ConfigFileOptsTestCase(BaseTestCase):
 
     def setUp(self):
-        super(ConfigFileOptsTestCase, self).setUp()
+        super().setUp()
         self.logger = self.useFixture(
             fixtures.FakeLogger(
                 format='%(message)s',
@@ -2284,7 +2284,7 @@ class ConfigFileReloadTestCase(BaseTestCase):
 
 class ConfigFileMutateTestCase(BaseTestCase):
     def setUp(self):
-        super(ConfigFileMutateTestCase, self).setUp()
+        super().setUp()
         self.my_group = cfg.OptGroup('group', 'group options')
         self.conf.register_group(self.my_group)
 
@@ -4013,7 +4013,7 @@ class OptDumpingTestCase(BaseTestCase):
             self.logged.append(fmt % args)
 
     def setUp(self):
-        super(OptDumpingTestCase, self).setUp()
+        super().setUp()
         self._args = ['--foo', 'this', '--blaa-bar', 'that',
                       '--blaa-key', 'admin', '--passwd', 'hush']
 
@@ -4135,7 +4135,7 @@ class ConfigParserTestCase(BaseTestCase):
 
 class NamespaceTestCase(BaseTestCase):
     def setUp(self):
-        super(NamespaceTestCase, self).setUp()
+        super().setUp()
         self.ns = cfg._Namespace(self.conf)
 
     def read(self, *texts):
@@ -5002,7 +5002,7 @@ class SectionsTestCase(BaseTestCase):
 
 class DeprecationWarningTestBase(BaseTestCase):
     def setUp(self):
-        super(DeprecationWarningTestBase, self).setUp()
+        super().setUp()
         self.log_fixture = self.useFixture(fixtures.FakeLogger())
         self._parser_class = cfg.ConfigParser
 
@@ -5162,7 +5162,7 @@ class DeprecationWarningTestsNoOsloLog(DeprecationWarningTests):
     log_prefix = ''
 
     def setUp(self):
-        super(DeprecationWarningTestsNoOsloLog, self).setUp()
+        super().setUp()
         # NOTE(bnemec): For some reason if I apply this as a class decorator
         # it ends up applying to the parent class too and breaks those tests.
         self.useFixture(fixtures.MockPatchObject(cfg, 'oslo_log', None))
diff --git a/oslo_config/tests/test_generator.py b/oslo_config/tests/test_generator.py
index 40704c68..54fb3101 100644
--- a/oslo_config/tests/test_generator.py
+++ b/oslo_config/tests/test_generator.py
@@ -952,7 +952,7 @@ class GeneratorTestCase(base.BaseTestCase):
             cls.output_file_scenarios)
 
     def setUp(self):
-        super(GeneratorTestCase, self).setUp()
+        super().setUp()
 
         self.conf = cfg.ConfigOpts()
         self.config_fixture = config_fixture.Config(self.conf)
@@ -1007,7 +1007,7 @@ class GeneratorTestCase(base.BaseTestCase):
         if self.stdout:
             self.assertEqual(self.expected, stdout.getvalue())
         else:
-            with open(output_file, 'r') as f:
+            with open(output_file) as f:
                 actual = f.read()
             self.assertEqual(self.expected, actual)
 
@@ -1021,7 +1021,7 @@ class GeneratorTestCase(base.BaseTestCase):
 class GeneratorFileHandlingTestCase(base.BaseTestCase):
 
     def setUp(self):
-        super(GeneratorFileHandlingTestCase, self).setUp()
+        super().setUp()
 
         self.conf = cfg.ConfigOpts()
         self.config_fixture = config_fixture.Config(self.conf)
@@ -1056,7 +1056,7 @@ class GeneratorFileHandlingTestCase(base.BaseTestCase):
 class DriverOptionTestCase(base.BaseTestCase):
 
     def setUp(self):
-        super(DriverOptionTestCase, self).setUp()
+        super().setUp()
 
         self.conf = cfg.ConfigOpts()
         self.config_fixture = config_fixture.Config(self.conf)
@@ -1390,7 +1390,7 @@ class MachineReadableGeneratorTestCase(base.BaseTestCase):
         ]
 
     def setUp(self):
-        super(MachineReadableGeneratorTestCase, self).setUp()
+        super().setUp()
 
         self.conf = cfg.ConfigOpts()
         self.config_fixture = config_fixture.Config(self.conf)
@@ -1550,7 +1550,7 @@ class GeneratorAdditionalTestCase(base.BaseTestCase):
             generator._output_opts(formatter, 'DEFAULT', groups.pop('DEFAULT'))
         expected = '''[DEFAULT]
 '''
-        with open(tmp_file, 'r') as f:
+        with open(tmp_file) as f:
             actual = f.read()
         self.assertEqual(expected, actual)
 
@@ -1573,7 +1573,7 @@ class GeneratorAdditionalTestCase(base.BaseTestCase):
 # foo option (string value)
 #foo = fred
 '''
-        with open(tmp_file, 'r') as f:
+        with open(tmp_file) as f:
             actual = f.read()
         self.assertEqual(expected, actual)
 
@@ -1593,8 +1593,8 @@ class GeneratorAdditionalTestCase(base.BaseTestCase):
 #
 
 # a list (list value)
-#list_opt = %(default)s
-''' % {'default': default}
+#list_opt = {default}
+'''.format(default=default)
         generator._output_opts(formatter, 'alpha', groups.pop('alpha'))
         f.close()
         content = open(tmp_file).read()
@@ -1733,7 +1733,7 @@ bar = <None>
 # bars foo (string value)
 bars = <None>
 '''
-        with open(tmp_file, 'r') as f:
+        with open(tmp_file) as f:
             actual = f.read()
         self.assertEqual(expected, actual)
 
@@ -1795,7 +1795,7 @@ messages!""")]
 # messages! (string value)
 #bar = <None>
 '''
-        with open(tmp_file, 'r') as f:
+        with open(tmp_file) as f:
             actual = f.read()
         self.assertEqual(expected, actual)
 
@@ -1841,7 +1841,7 @@ class AdvancedOptionsTestCase(base.BaseTestCase):
 # effect on stability and/or performance.
 #bars = true
 '''
-        with open(tmp_file, 'r') as f:
+        with open(tmp_file) as f:
             actual = f.read()
         self.assertEqual(expected, actual)
 
diff --git a/oslo_config/tests/test_get_location.py b/oslo_config/tests/test_get_location.py
index d06271ae..a1b496b8 100644
--- a/oslo_config/tests/test_get_location.py
+++ b/oslo_config/tests/test_get_location.py
@@ -10,7 +10,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import io
 import tempfile
 import textwrap
 
@@ -50,7 +49,7 @@ class LocationTestCase(base.BaseTestCase):
 class GetLocationTestCase(base.BaseTestCase):
 
     def setUp(self):
-        super(GetLocationTestCase, self).setUp()
+        super().setUp()
 
         def _clear():
             cfg._show_caller_details = False
@@ -136,7 +135,7 @@ class GetLocationTestCase(base.BaseTestCase):
 
     def _write_opt_to_tmp_file(self, group, option, value):
         filename = tempfile.mktemp()
-        with io.open(filename, 'w', encoding='utf-8') as f:
+        with open(filename, 'w', encoding='utf-8') as f:
             f.write(textwrap.dedent('''
             [{group}]
             {option} = {value}
diff --git a/oslo_config/tests/test_sources.py b/oslo_config/tests/test_sources.py
index 7c1e8580..90eeca52 100644
--- a/oslo_config/tests/test_sources.py
+++ b/oslo_config/tests/test_sources.py
@@ -33,7 +33,7 @@ class TestProcessingSources(base.BaseTestCase):
     # is when the 'config_source' option is processed.
 
     def setUp(self):
-        super(TestProcessingSources, self).setUp()
+        super().setUp()
         self.conf = cfg.ConfigOpts()
         self.conf_fixture = self.useFixture(fixture.Config(self.conf))
 
@@ -85,7 +85,7 @@ class TestLoading(base.BaseTestCase):
     # ConfigOpts setup is done in __call__().
 
     def setUp(self):
-        super(TestLoading, self).setUp()
+        super().setUp()
         self.conf = cfg.ConfigOpts()
         self.conf_fixture = self.useFixture(fixture.Config(self.conf))
 
@@ -117,7 +117,7 @@ class TestLoading(base.BaseTestCase):
 class TestEnvironmentConfigurationSource(base.BaseTestCase):
 
     def setUp(self):
-        super(TestEnvironmentConfigurationSource, self).setUp()
+        super().setUp()
         self.conf = cfg.ConfigOpts()
         self.conf_fixture = self.useFixture(fixture.Config(self.conf))
         self.conf.register_opt(cfg.StrOpt('bar'), 'foo')
@@ -258,7 +258,7 @@ def opts_to_ini(uri, *args, **kwargs):
 class URISourceTestCase(base.BaseTestCase):
 
     def setUp(self):
-        super(URISourceTestCase, self).setUp()
+        super().setUp()
         self.conf = cfg.ConfigOpts()
         self.conf_fixture = self.useFixture(fixture.Config(self.conf))
 
diff --git a/oslo_config/tests/test_types.py b/oslo_config/tests/test_types.py
index 7ef3439f..f8b7bba0 100644
--- a/oslo_config/tests/test_types.py
+++ b/oslo_config/tests/test_types.py
@@ -22,14 +22,14 @@ class ConfigTypeTests(unittest.TestCase):
     def test_none_concrete_class(self):
         class MyString(types.ConfigType):
             def __init__(self, type_name='mystring value'):
-                super(MyString, self).__init__(type_name=type_name)
+                super().__init__(type_name=type_name)
 
         self.assertRaises(TypeError, MyString)
 
     def test_concrete_class(self):
         class MyString(types.ConfigType):
             def __init__(self, type_name='mystring value'):
-                super(MyString, self).__init__(type_name=type_name)
+                super().__init__(type_name=type_name)
 
             def _formatter(self, value):
                 return value
@@ -39,7 +39,7 @@ class ConfigTypeTests(unittest.TestCase):
 
 class TypeTestHelper:
     def setUp(self):
-        super(TypeTestHelper, self).setUp()
+        super().setUp()
         self.type_instance = self.type
 
     def assertConvertedValue(self, s, expected):
diff --git a/oslo_config/tests/test_validator.py b/oslo_config/tests/test_validator.py
index 383340f2..7786c75b 100644
--- a/oslo_config/tests/test_validator.py
+++ b/oslo_config/tests/test_validator.py
@@ -83,7 +83,7 @@ opt = value
 
 class TestValidator(base.BaseTestCase):
     def setUp(self):
-        super(TestValidator, self).setUp()
+        super().setUp()
         self.conf = cfg.ConfigOpts()
         self.conf_fixture = self.useFixture(fixture.Config(self.conf))
         validator._register_cli_opts(self.conf)
diff --git a/oslo_config/types.py b/oslo_config/types.py
index 9fef13af..d9835ca6 100644
--- a/oslo_config/types.py
+++ b/oslo_config/types.py
@@ -108,7 +108,7 @@ class String(ConfigType):
     def __init__(self, choices=None, quotes=False, regex=None,
                  ignore_case=False, max_length=None,
                  type_name='string value'):
-        super(String, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
         if choices and regex:
             raise ValueError("'choices' and 'regex' cannot both be specified")
 
@@ -165,7 +165,7 @@ class String(ConfigType):
             return value
 
         raise ValueError(
-            'Valid values are [%s], but found %s' % (
+            'Valid values are [{}], but found {}'.format(
                 ', '.join([str(v) for v in self.choices]),
                 repr(value)))
 
@@ -184,8 +184,8 @@ class String(ConfigType):
             (self.__class__ == other.__class__) and
             (self.quotes == other.quotes) and
             (self.regex == other.regex) and
-            (set([x for x in self.choices or []]) ==
-                set([x for x in other.choices or []]) if
+            ({x for x in self.choices or []} ==
+                {x for x in other.choices or []} if
              self.choices and other.choices else
              self.choices == other.choices)
         )
@@ -198,7 +198,7 @@ class MultiString(String):
     """Multi-valued string."""
 
     def __init__(self, type_name='multi valued'):
-        super(MultiString, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
 
     NONE_DEFAULT = ['']
 
@@ -235,7 +235,7 @@ class Boolean(ConfigType):
     FALSE_VALUES = ['false', '0', 'off', 'no']
 
     def __init__(self, type_name='boolean value'):
-        super(Boolean, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
 
     def __call__(self, value):
         if isinstance(value, bool):
@@ -279,7 +279,7 @@ class Number(ConfigType):
 
     def __init__(self, num_type, type_name,
                  min=None, max=None, choices=None):
-        super(Number, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
 
         if min is not None and max is not None and max < min:
             raise ValueError('Max value is less than min value')
@@ -319,8 +319,9 @@ class Number(ConfigType):
                                  self.max)
         else:
             if value not in self.choices:
-                raise ValueError('Valid values are %r, but found %g' % (
-                                 self.choices, value))
+                raise ValueError(
+                    'Valid values are {!r}, but found {:g}'.format(
+                        self.choices, value))
         return value
 
     def __repr__(self):
@@ -342,8 +343,8 @@ class Number(ConfigType):
             (self.__class__ == other.__class__) and
             (self.min == other.min) and
             (self.max == other.max) and
-            (set([x for x in self.choices or []]) ==
-                set([x for x in other.choices or []]) if
+            ({x for x in self.choices or []} ==
+                {x for x in other.choices or []} if
              self.choices and other.choices else
              self.choices == other.choices)
         )
@@ -385,8 +386,8 @@ class Integer(Number):
 
     def __init__(self, min=None, max=None, type_name='integer value',
                  choices=None):
-        super(Integer, self).__init__(int, type_name, min=min, max=max,
-                                      choices=choices)
+        super().__init__(int, type_name, min=min, max=max,
+                         choices=choices)
 
 
 class Float(Number):
@@ -408,7 +409,7 @@ class Float(Number):
     """
 
     def __init__(self, min=None, max=None, type_name='floating point value'):
-        super(Float, self).__init__(float, type_name, min=min, max=max)
+        super().__init__(float, type_name, min=min, max=max)
 
 
 class Port(Integer):
@@ -443,8 +444,8 @@ class Port(Integer):
             raise ValueError('Max value cannot be more than %(max)d' %
                              {'max': self.PORT_MAX})
 
-        super(Port, self).__init__(min=min, max=max, type_name=type_name,
-                                   choices=choices)
+        super().__init__(min=min, max=max, type_name=type_name,
+                         choices=choices)
 
 
 class List(ConfigType):
@@ -470,7 +471,7 @@ class List(ConfigType):
     """
 
     def __init__(self, item_type=None, bounds=False, type_name='list value'):
-        super(List, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
 
         if item_type is None:
             item_type = String()
@@ -559,7 +560,7 @@ class Range(ConfigType):
 
     def __init__(self, min=None, max=None, inclusive=True,
                  type_name='range value'):
-        super(Range, self).__init__(type_name)
+        super().__init__(type_name)
         self.min = min
         self.max = max
         self.inclusive = inclusive
@@ -567,7 +568,7 @@ class Range(ConfigType):
     def __call__(self, value):
         value = str(value)
         num = "0|-?[1-9][0-9]*"
-        m = re.match("^(%s)(?:-(%s))?$" % (num, num), value)
+        m = re.match("^({})(?:-({}))?$".format(num, num), value)
         if not m:
             raise ValueError('Invalid Range: %s' % value)
         left = int(m.group(1))
@@ -620,7 +621,7 @@ class Dict(ConfigType):
 
     def __init__(self, value_type=None, bounds=False, type_name='dict value',
                  key_value_separator=':'):
-        super(Dict, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
 
         if value_type is None:
             value_type = String()
@@ -721,7 +722,7 @@ class IPAddress(ConfigType):
     """
 
     def __init__(self, version=None, type_name='IP address value'):
-        super(IPAddress, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
         version_checkers = {
             None: self._check_both_versions,
             4: self._check_ipv4,
@@ -775,7 +776,7 @@ class Hostname(ConfigType):
     HOSTNAME_REGEX = '(?!-)[A-Z0-9-]{1,63}(?<!-)$'
 
     def __init__(self, type_name='hostname value'):
-        super(Hostname, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
 
     def __call__(self, value, regex=HOSTNAME_REGEX):
         """Check hostname is valid.
@@ -838,7 +839,7 @@ class HostAddress(ConfigType):
 
         """
 
-        super(HostAddress, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
         self.ip_address = IPAddress(version, type_name)
         self.hostname = Hostname('localhost')
 
@@ -857,7 +858,7 @@ class HostAddress(ConfigType):
                 value = self.hostname(value)
             except ValueError:
                 raise ValueError(
-                    "%s is not a valid host address" % (value,))
+                    "{} is not a valid host address".format(value))
         return value
 
     def __repr__(self):
@@ -887,7 +888,7 @@ class HostDomain(HostAddress):
 
         """
 
-        super(HostDomain, self).__init__(version=version, type_name=type_name)
+        super().__init__(version=version, type_name=type_name)
 
     def __call__(self, value):
         """Checks if is a valid IP/hostname.
@@ -898,7 +899,7 @@ class HostDomain(HostAddress):
         """
 
         try:
-            value = super(HostDomain, self).__call__(value)
+            value = super().__call__(value)
         except ValueError:
             # Check if domain is valid
             # Add support of underscore
@@ -909,7 +910,7 @@ class HostDomain(HostAddress):
                 value = self.hostname(value, regex=self.DOMAIN_REGEX)
             except ValueError:
                 raise ValueError(
-                    "%s is not a valid host address" % (value,))
+                    "{} is not a valid host address".format(value))
         return value
 
     def __repr__(self):
@@ -936,7 +937,7 @@ class URI(ConfigType):
     """
 
     def __init__(self, max_length=None, schemes=None, type_name='uri value'):
-        super(URI, self).__init__(type_name=type_name)
+        super().__init__(type_name=type_name)
         self.max_length = max_length
         self.schemes = schemes
 
diff --git a/oslo_config/validator.py b/oslo_config/validator.py
index 4ec1a7e3..4ed42ccd 100644
--- a/oslo_config/validator.py
+++ b/oslo_config/validator.py
@@ -130,7 +130,7 @@ def _validate_defaults(sections, opt_data, conf):
             # Apparently, there's multiple naming conventions for
             # options, 'name' is mostly with hyphens, and 'dest'
             # is represented with underscores.
-            opt_names = set([opt['name'], opt.get('dest')])
+            opt_names = {opt['name'], opt.get('dest')}
             if not opt_names.intersection(sections[group]):
                 continue
             try:
diff --git a/releasenotes/source/conf.py b/releasenotes/source/conf.py
index 8fd6fe92..5af97457 100644
--- a/releasenotes/source/conf.py
+++ b/releasenotes/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at