diff --git a/oslo_utils/excutils.py b/oslo_utils/excutils.py
index ae5f7e31..a3b15bf1 100644
--- a/oslo_utils/excutils.py
+++ b/oslo_utils/excutils.py
@@ -274,8 +274,8 @@ def forever_retry_uncaught_exceptions(*args, **kwargs):
                         # The watch has expired or the exception message
                         # changed, so time to log it again...
                         logging.exception(
-                            'Unexpected exception occurred %d time(s)... '
-                            'retrying.' % same_failure_count
+                            f'Unexpected exception occurred '
+                            f'{same_failure_count} time(s)... retrying.'
                         )
                         if not watch.has_started():
                             watch.start()
diff --git a/oslo_utils/imageutils/format_inspector.py b/oslo_utils/imageutils/format_inspector.py
index 329fcfb1..5433e435 100644
--- a/oslo_utils/imageutils/format_inspector.py
+++ b/oslo_utils/imageutils/format_inspector.py
@@ -792,7 +792,7 @@ class VHDXInspector(FileInspector):
             )
 
         if count >= 2048:
-            raise ImageFormatError('Region count is %i (limit 2047)' % count)
+            raise ImageFormatError('Region count is {int(count)} (limit 2047)')
 
         # Process the regions until we find the metadata one; grab the
         # offset and return
@@ -849,7 +849,7 @@ class VHDXInspector(FileInspector):
 
         if count >= 2048:
             raise ImageFormatError(
-                'Metadata item count is %i (limit 2047)' % count
+                'Metadata item count is {int(count)} (limit 2047)'
             )
 
         for i in range(0, count):
@@ -1003,7 +1003,7 @@ class VMDKInspector(FileInspector):
             raise ImageFormatError(f'Signature KDMV not found: {sig!r}')
 
         if ver not in (1, 2, 3):
-            raise ImageFormatError('Unsupported format version %i' % ver)
+            raise ImageFormatError('Unsupported format version {int(ver)}')
 
         if gdOffset == self.GD_AT_END and not self.has_region('footer'):
             # This means we have a footer, which takes precedence over the
@@ -1364,7 +1364,9 @@ class GPTInspector(FileInspector):
                 sizelba,
             ) = struct.unpack('<B3BB3BII', pte)
             if boot not in (0x00, 0x80):
-                raise SafetyViolation('MBR PTE %i has invalid boot flag' % i)
+                raise SafetyViolation(
+                    f'MBR PTE {int(i)} has invalid boot flag'
+                )
             if ostype != 0:
                 valid_partitions.append(i)
             if ostype == 0xEE:
@@ -1415,7 +1417,7 @@ class LUKSInspector(FileInspector):
         header = self.header_items
         if header['version'] != 1:
             raise SafetyViolation(
-                'LUKS version %i is not supported' % header['version']
+                f'LUKS version {int(header["version"])} is not supported'
             )
 
     @property
diff --git a/oslo_utils/tests/imageutils/test_format_inspector.py b/oslo_utils/tests/imageutils/test_format_inspector.py
index a9554951..ae24e78d 100644
--- a/oslo_utils/tests/imageutils/test_format_inspector.py
+++ b/oslo_utils/tests/imageutils/test_format_inspector.py
@@ -89,7 +89,7 @@ class TestFormatInspectors(test_base.BaseTestCase):
         fn = tempfile.mktemp(prefix=prefix, suffix='.iso')
         self._created_files.append(fn)
         subprocess.check_output(
-            'dd if=/dev/zero of=%s bs=1M count=%i' % (fn, size), shell=True
+            f'dd if=/dev/zero of={fn} bs=1M count={int(size)}', shell=True
         )
         # We need to use different file as input and output as the behavior
         # of mkisofs is version dependent if both the input and the output
@@ -140,7 +140,7 @@ class TestFormatInspectors(test_base.BaseTestCase):
             '-o',
             'key-secret=sec0',
             fn,
-            '%i' % image_size,
+            f'{int(image_size)}',
         ]
         subprocess.check_output(' '.join(cmd), shell=True)
         return fn
@@ -200,7 +200,7 @@ class TestFormatInspectors(test_base.BaseTestCase):
         fn = tempfile.mktemp(prefix=prefix, suffix=f'.{fmt}')
         self._created_files.append(fn)
         subprocess.check_output(
-            'qemu-img create -f %s %s %s %i' % (fmt, opt, fn, size), shell=True
+            f'qemu-img create -f {fmt} {opt} {fn} {int(size)}', shell=True
         )
         return fn
 
@@ -223,13 +223,14 @@ class TestFormatInspectors(test_base.BaseTestCase):
         # Create a file with pseudo-random data, otherwise it will get
         # compressed in the streamOptimized format
         subprocess.check_output(
-            'dd if=/dev/urandom of=%s bs=1M count=%i' % (raw, size_mb),
+            f'dd if=/dev/urandom of={raw} bs=1M count={int(size_mb)}',
             shell=True,
         )
 
         # Convert it to VMDK
         subprocess.check_output(
-            f'qemu-img convert -f raw -O vmdk -o subformat={subformat} -S 0 {raw} {fn}',
+            f'qemu-img convert -f raw -O vmdk -o subformat={subformat} '
+            f'-S 0 {raw} {fn}',
             shell=True,
         )
         return fn
@@ -287,14 +288,14 @@ class TestFormatInspectors(test_base.BaseTestCase):
             fmt = self._test_format_at_block_size(format_name, img, block_size)
             self.assertTrue(
                 fmt.format_match,
-                'Failed to match %s at size %i block %i'
-                % (format_name, image_size, block_size),
+                f'Failed to match {format_name} at '
+                f'size {int(image_size)} block {int(block_size)}',
             )
             self.assertEqual(
                 virtual_size,
                 fmt.virtual_size,
-                ('Failed to calculate size for %s at size %i block %i')
-                % (format_name, image_size, block_size),
+                f'Failed to calculate size for {format_name} at '
+                f'size {int(image_size)} block {int(block_size)}',
             )
             memory = sum(fmt.context_info.values())
             self.assertLess(
@@ -481,14 +482,14 @@ class TestFormatInspectors(test_base.BaseTestCase):
             fmt = self._test_format_at_block_size(format_name, img, block_size)
             self.assertTrue(
                 fmt.format_match,
-                'Failed to match %s at size %i block %i'
-                % (format_name, image_size, block_size),
+                f'Failed to match {format_name} at '
+                f'size {int(image_size)} block {int(block_size)}',
             )
             self.assertEqual(
                 virtual_size,
                 fmt.virtual_size,
-                ('Failed to calculate size for %s at size %i block %i')
-                % (format_name, image_size, block_size),
+                f'Failed to calculate size for {format_name} at '
+                f'size {int(image_size)} block {int(block_size)}',
             )
             memory = sum(fmt.context_info.values())
             self.assertLess(
diff --git a/oslo_utils/tests/imageutils/test_qemu.py b/oslo_utils/tests/imageutils/test_qemu.py
index 6e41294f..d717460f 100644
--- a/oslo_utils/tests/imageutils/test_qemu.py
+++ b/oslo_utils/tests/imageutils/test_qemu.py
@@ -132,10 +132,10 @@ class ImageUtilsHumanRawTestCase(test_base.BaseTestCase):
         )
         for i in range(self.snapshot_count):
             img_info = img_info + (
-                '%d        '
-                'd9a9784a500742a7bb95627bb3aace38    '
-                '0 2012-08-20 10:52:46 '
-                '00:00:00.000' % (i + 1),
+                f'{i + 1}        '
+                f'd9a9784a500742a7bb95627bb3aace38    '
+                f'0 2012-08-20 10:52:46 '
+                f'00:00:00.000',
             )
         return img_info
 
diff --git a/oslo_utils/tests/test_excutils.py b/oslo_utils/tests/test_excutils.py
index aea4a3d2..f80dd5bd 100644
--- a/oslo_utils/tests/test_excutils.py
+++ b/oslo_utils/tests/test_excutils.py
@@ -175,9 +175,7 @@ class ForeverRetryUncaughtExceptionsTest(test_base.BaseTestCase):
     @mock.patch.object(logging, 'exception')
     @mock.patch.object(timeutils, 'now')
     def test_exc_retrier_1exc_gives_1log(self, mock_now, mock_log):
-        self._exceptions = [
-            Exception('unexpected %d' % 1),
-        ]
+        self._exceptions = [Exception('unexpected 1')]
         mock_now.side_effect = [0]
 
         self.exception_generator()
@@ -185,7 +183,7 @@ class ForeverRetryUncaughtExceptionsTest(test_base.BaseTestCase):
         self.assertEqual([], self._exceptions)
         # log should only be called once
         mock_log.assert_called_once_with(
-            'Unexpected exception occurred %d time(s)... retrying.' % 1
+            'Unexpected exception occurred 1 time(s)... retrying.'
         )
         mock_now.assert_has_calls(
             [
diff --git a/pyproject.toml b/pyproject.toml
index b66e3887..8a21887b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -44,7 +44,6 @@ docstring-code-format = true
 
 [tool.ruff.lint]
 select = ["E4", "E7", "E9", "F", "S", "UP"]
-ignore = ["UP031"]
 
 [tool.ruff.lint.per-file-ignores]
 "oslo_utils/tests/*" = ["S"]
diff --git a/tools/perf_test_mask_password.py b/tools/perf_test_mask_password.py
index 39ec0486..7f1be8a0 100644
--- a/tools/perf_test_mask_password.py
+++ b/tools/perf_test_mask_password.py
@@ -29,7 +29,7 @@ infile = 'large_json_payload.txt'
 
 with open(infile) as f:
     input_str = f.read()
-print('payload has %d bytes' % len(input_str))
+print(f'payload has {len(input_str)} bytes')
 
 for pattern in strutils._SANITIZE_PATTERNS_2['admin_pass']:
     print(f'\ntesting {pattern.pattern}')