diff --git a/avocado/core/job.py b/avocado/core/job.py
index 58bef90e1d58611c3cc75884c4b13bb61cc2dece..1ff79a9cd73200a08ac8a35ffa0a89f5d5c7dd98 100644
--- a/avocado/core/job.py
+++ b/avocado/core/job.py
@@ -402,10 +402,10 @@ class Job(object):
     def _log_avocado_datadir(self):
         LOG_JOB.info('Avocado Data Directories:')
         LOG_JOB.info('')
-        LOG_JOB.info('base     ' + data_dir.get_base_dir())
-        LOG_JOB.info('tests    ' + data_dir.get_test_dir())
-        LOG_JOB.info('data     ' + data_dir.get_data_dir())
-        LOG_JOB.info('logs     ' + self.logdir)
+        LOG_JOB.info('base     %s', data_dir.get_base_dir())
+        LOG_JOB.info('tests    %s', data_dir.get_test_dir())
+        LOG_JOB.info('data     %s', data_dir.get_data_dir())
+        LOG_JOB.info('logs     %s', self.logdir)
         LOG_JOB.info('')
 
     @staticmethod
@@ -540,7 +540,7 @@ class Job(object):
             self.exitcode |= exit_codes.AVOCADO_JOB_FAIL
             return self.exitcode
         except exceptions.OptionValidationError as details:
-            self.log.error('\n' + str(details))
+            self.log.error('\n%s', str(details))
             self.exitcode |= exit_codes.AVOCADO_JOB_FAIL
             return self.exitcode
 
diff --git a/avocado/core/output.py b/avocado/core/output.py
index 2495aa50ecced79c8befd69e221ce99c111658f6..064c52111b7fddeaf96262f4587b28c2f9ce6cf2 100644
--- a/avocado/core/output.py
+++ b/avocado/core/output.py
@@ -326,8 +326,7 @@ class StdOutput(object):
         except RuntimeError as details:
             # Paginator not available
             logging.getLogger('avocado.app.debug').error("Failed to enable "
-                                                         "paginator: %s"
-                                                         % details)
+                                                         "paginator: %s", details)
             return
         self.stdout = self.stderr = paginator
 
diff --git a/avocado/core/runner.py b/avocado/core/runner.py
index 8b39fc6cfb7f7c55cffc4b15a6abd478b6b93347..ab2732cac53d012fa9c752b5ea50b6e3c27e3350 100644
--- a/avocado/core/runner.py
+++ b/avocado/core/runner.py
@@ -378,13 +378,14 @@ class TestRunner(object):
                 return
             with sigtstp:
                 msg = "ctrl+z pressed, %%s test (%s)" % proc.pid
+                app_log_msg = '\n%s' % msg
                 if self.sigstopped:
-                    APP_LOG.info("\n" + msg, "resumming")
+                    APP_LOG.info(app_log_msg, "resumming")
                     TEST_LOG.info(msg, "resumming")
                     process.kill_process_tree(proc.pid, signal.SIGCONT, False)
                     self.sigstopped = False
                 else:
-                    APP_LOG.info("\n" + msg, "stopping")
+                    APP_LOG.info(app_log_msg, "stopping")
                     TEST_LOG.info(msg, "stopping")
                     process.kill_process_tree(proc.pid, signal.SIGSTOP, False)
                     self.sigstopped = True
diff --git a/avocado/core/sysinfo.py b/avocado/core/sysinfo.py
index a7395e8f5694e6f86ddbd29757c5e66b5811bba7..c319d8af7e8fe334440d1c081c188657ab7a7d0f 100644
--- a/avocado/core/sysinfo.py
+++ b/avocado/core/sysinfo.py
@@ -213,7 +213,7 @@ class Daemon(Command):
                                                    stderr=subprocess.STDOUT,
                                                    shell=False, env=env)
         except OSError:
-            log.debug("Not logging  %s (command could not be run)" % self.cmd)
+            log.debug("Not logging  %s (command could not be run)", self.cmd)
 
     def stop(self):
         """
diff --git a/avocado/plugins/config.py b/avocado/plugins/config.py
index 78f2911e2ccb76760a44ac43834967eeacc4c3c2..32e693f3f7f633eae25e06c6cde6c3e6eee2010f 100644
--- a/avocado/plugins/config.py
+++ b/avocado/plugins/config.py
@@ -39,11 +39,11 @@ class Config(CLICmd):
     def run(self, args):
         LOG_UI.info('Config files read (in order):')
         for cfg_path in settings.config_paths:
-            LOG_UI.debug('    %s' % cfg_path)
+            LOG_UI.debug('    %s', cfg_path)
         if settings.config_paths_failed:
             LOG_UI.error('\nConfig files that failed to read:')
             for cfg_path in settings.config_paths_failed:
-                LOG_UI.error('    %s' % cfg_path)
+                LOG_UI.error('    %s', cfg_path)
         LOG_UI.debug("")
         if not args.datadir:
             blength = 0
@@ -66,8 +66,8 @@ class Config(CLICmd):
             LOG_UI.debug("file to customize values")
             LOG_UI.debug('')
             LOG_UI.info('Avocado Data Directories:')
-            LOG_UI.debug('    base     ' + data_dir.get_base_dir())
-            LOG_UI.debug('    tests    ' + data_dir.get_test_dir())
-            LOG_UI.debug('    data     ' + data_dir.get_data_dir())
-            LOG_UI.debug('    logs     ' + data_dir.get_logs_dir())
-            LOG_UI.debug('    cache    ' + ", ".join(data_dir.get_cache_dirs()))
+            LOG_UI.debug('    base     %s', data_dir.get_base_dir())
+            LOG_UI.debug('    tests    %s', data_dir.get_test_dir())
+            LOG_UI.debug('    data     %s', data_dir.get_data_dir())
+            LOG_UI.debug('    logs     %s', data_dir.get_logs_dir())
+            LOG_UI.debug('    cache    %s', ", ".join(data_dir.get_cache_dirs()))
diff --git a/avocado/utils/asset.py b/avocado/utils/asset.py
index 8c35849c4a6ec5effc19731d75a037e592bf7198..85b42228aad96dcd616045ff3532b21357488e2d 100644
--- a/avocado/utils/asset.py
+++ b/avocado/utils/asset.py
@@ -159,7 +159,7 @@ class Asset(object):
                             return asset_file
                 except:
                     exc_type, exc_value = sys.exc_info()[:2]
-                    log.error('%s: %s' % (exc_type.__name__, exc_value))
+                    log.error('%s: %s', exc_type.__name__, exc_value)
 
         # If we get to this point, we have to download it from a location.
         # A writable cache directory is then needed. The first available
@@ -190,7 +190,7 @@ class Asset(object):
                     return asset_file
             except:
                 exc_type, exc_value = sys.exc_info()[:2]
-                log.error('%s: %s' % (exc_type.__name__, exc_value))
+                log.error('%s: %s', exc_type.__name__, exc_value)
 
         raise EnvironmentError("Failed to fetch %s." % basename)
 
diff --git a/avocado/utils/data_factory.py b/avocado/utils/data_factory.py
index 093cd0c3277a36e1b1156c57518cf6b8c277a17d..93106860781a85127e7b4e4ad5ace0c1fc182146 100644
--- a/avocado/utils/data_factory.py
+++ b/avocado/utils/data_factory.py
@@ -82,8 +82,8 @@ def make_dir_and_populate(basedir='/tmp'):
                 os.write(fd, generate_random_string(str_length))
             os.close(fd)
     except OSError as details:
-        log.error("Failed to generate dir in '%s' and populate: %s" %
-                  (basedir, details))
+        log_msg = "Failed to generate dir in '%s' and populate: %s"
+        log.error(log_msg, basedir, details)
         return None
 
     return path
diff --git a/avocado/utils/download.py b/avocado/utils/download.py
index 907c7fdc192967d0a10f4c35088758a6c5ca88a6..a2c3cdf5f6a8512ab27b275da926b7e87d024475 100644
--- a/avocado/utils/download.py
+++ b/avocado/utils/download.py
@@ -171,7 +171,7 @@ def get_file(src, dst, permissions=None, hash_expected=None,
     while not hash_file == hash_expected:
         hash_file = _verify_hash(_get_file(src, dst, permissions))
         if hash_file != hash_expected:
-            log.error("It seems that dst %s is corrupted" % dst)
+            log.error("It seems that dst %s is corrupted", dst)
             download_failures += 1
         if download_failures > download_retries:
             raise EnvironmentError("Failed to retrieve %s. "
diff --git a/avocado/utils/genio.py b/avocado/utils/genio.py
index 3b7cc5f752a2bb9f567919897f8577f9f237ff76..f00a047b6ad15d57b94ca0e67fa5ba445130c48a 100644
--- a/avocado/utils/genio.py
+++ b/avocado/utils/genio.py
@@ -99,7 +99,7 @@ def ask(question, auto=False):
     :rtype: str
     """
     if auto:
-        log.info("%s (y/n) y" % question)
+        log.info("%s (y/n) y", question)
         return "y"
     return input("%s (y/n) " % question)
 
diff --git a/avocado/utils/lv_utils.py b/avocado/utils/lv_utils.py
index ff2806db706664f51f7175f7f87373b966ecd311..1af69477bd8b0641f83ce96f74fe654cc1511a7b 100644
--- a/avocado/utils/lv_utils.py
+++ b/avocado/utils/lv_utils.py
@@ -448,8 +448,8 @@ def lv_take_snapshot(vg_name, lv_name,
             re.search(re.escape(lv_snapshot_name + " [active]"),
                       process.run("lvdisplay", sudo=True).stdout)):
             # the above conditions detect if merge of snapshot was postponed
-            LOGGER.debug(("Logical volume %s is still active! " +
-                          "Attempting to deactivate..."), lv_name)
+            log_msg = "Logical volume %s is still active! Attempting to deactivate..."
+            LOGGER.debug(log_msg, lv_name)
             lv_reactivate(vg_name, lv_name)
             process.run(cmd, sudo=True)
         else:
@@ -491,8 +491,8 @@ def lv_revert(vg_name, lv_name, lv_snapshot_name):
         if ('Snapshot could not be found' in ex.result.stderr and
                 re.search(active_lv_pattern, lvdisplay_output) or
                 "The Logical volume %s is still active" % lv_name in ex.result.stderr):
-            LOGGER.debug(("Logical volume %s is still active! " +
-                          "Attempting to deactivate..."), lv_name)
+            log_msg = "Logical volume %s is still active! Attempting to deactivate..."
+            LOGGER.debug(log_msg, lv_name)
             lv_reactivate(vg_name, lv_name)
             LOGGER.error("Continuing after reactivation")
         elif 'Snapshot could not be found' in ex.result.stderr:
@@ -533,8 +533,8 @@ def lv_reactivate(vg_name, lv_name, timeout=10):
         process.run("lvchange -ay /dev/%s/%s" % (vg_name, lv_name), sudo=True)
         time.sleep(timeout)
     except process.CmdError:
-        LOGGER.error(("Failed to reactivate %s - please, " +
-                      "nuke the process that uses it first."), lv_name)
+        log_msg = "Failed to reactivate %s - please, nuke the process that uses it first."
+        LOGGER.error(log_msg, lv_name)
         raise LVException("The Logical volume %s is still active" % lv_name)
 
 
diff --git a/avocado/utils/memory.py b/avocado/utils/memory.py
index 9524c803eb22d5cdffc8cec7a8a78f3155e422be..27e8e756af2a2e6ab88b78dcb62db71b26fd6011 100644
--- a/avocado/utils/memory.py
+++ b/avocado/utils/memory.py
@@ -394,7 +394,7 @@ def get_buddy_info(chunk_sizes, nodes="all", zones="all"):
         re_buddyinfo += "(%s)" % "|".join(nodes.split())
 
     if not re.findall(re_buddyinfo, buddy_info_content):
-        logging.warn("Can not find Nodes %s" % nodes)
+        logging.warn("Can not find Nodes %s", nodes)
         return None
     re_buddyinfo += r".*?zone\s+"
     if zones == "all":
@@ -402,7 +402,7 @@ def get_buddy_info(chunk_sizes, nodes="all", zones="all"):
     else:
         re_buddyinfo += "(%s)" % "|".join(zones.split())
     if not re.findall(re_buddyinfo, buddy_info_content):
-        logging.warn("Can not find zones %s" % zones)
+        logging.warn("Can not find zones %s", zones)
         return None
     re_buddyinfo += r"\s+([\s\d]+)"
 
diff --git a/avocado/utils/software_manager.py b/avocado/utils/software_manager.py
index 44b533f249277539a9f27b6a3bf6b5b6dbc7a6bb..3828a0c8c6aad8d5c9748c6751c3b28d5af35b58 100644
--- a/avocado/utils/software_manager.py
+++ b/avocado/utils/software_manager.py
@@ -662,7 +662,7 @@ class ZypperBackend(RpmBackend):
         except IndexError:
             ver = out
         self.pm_version = ver
-        log.debug('Zypper version: %s' % self.pm_version)
+        log.debug('Zypper version: %s', self.pm_version)
 
     def install(self, name):
         """
diff --git a/optional_plugins/html/avocado_result_html/__init__.py b/optional_plugins/html/avocado_result_html/__init__.py
index e80931151935671a8a4a7019229b4ff4937ab4e7..fbffdb3a2df8ce8ab9200c7d672547b32afe8548 100644
--- a/optional_plugins/html/avocado_result_html/__init__.py
+++ b/optional_plugins/html/avocado_result_html/__init__.py
@@ -253,7 +253,7 @@ class HTMLResult(Result):
                 report_contents = v.render('utf8')
         except UnicodeDecodeError as details:
             # FIXME: Remove me when UnicodeDecodeError problem is fixed
-            LOG_UI.critical("\n" + ("-" * 80))
+            LOG_UI.critical("\n%s", ("-" * 80))
             LOG_UI.critical("HTML failed to render the template: %s\n\n",
                             template)
             LOG_UI.critical("-" * 80)
diff --git a/optional_plugins/resultsdb/avocado_resultsdb/__init__.py b/optional_plugins/resultsdb/avocado_resultsdb/__init__.py
index 3cc736022b08e958d9ed83ad71c055310d4742c3..b2982bd4a6f94430542468e4d0d91ad13bedace1 100644
--- a/optional_plugins/resultsdb/avocado_resultsdb/__init__.py
+++ b/optional_plugins/resultsdb/avocado_resultsdb/__init__.py
@@ -162,8 +162,8 @@ class ResultsdbResult(Result):
     def render(self, result, job):
         if (getattr(job.args, 'resultsdb_logs', None) is not None and
                 getattr(job.args, 'stdout_claimed_by', None) is None):
-            LOG_UI.info("JOB URL    : %s/%s" % (job.args.resultsdb_logs,
-                                                os.path.basename(job.logdir)))
+            log_msg = "JOB URL    : %s/%s"
+            LOG_UI.info(log_msg, job.args.resultsdb_logs, os.path.basename(job.logdir))
 
 
 class ResultsdbCLI(CLI):
diff --git a/selftests/checkall b/selftests/checkall
index bff99aafb3829d9b2070adfecac973a6122538f3..7e664c3c8a96d595738414149022018ecc97d777 100755
--- a/selftests/checkall
+++ b/selftests/checkall
@@ -169,7 +169,7 @@ results_dir_content() {
 [ "$SKIP_RESULTSDIR_CHECK" ] || RESULTS_DIR_CONTENT="$(ls $RESULTS_DIR 2> /dev/null)"
 
 LINT_CMD="inspekt lint --exclude=.git"
-PYLINT_ENABLE="--enable R0401,W0101,W0102,W0104,W0105,W0106,W0107,W0108,W0109,W0111,W0120,W0122,W0123,W0124,W0125,W0150,W0199,W0211,W0222,W0232,W0233,W0301,W0312,W0401,W0404,W0406,W0410,W0601,W0602,W0603,W0604,W0611,W0612,W0614,W0622,W0623,W0640,W0711,W1202,W1300,W1301,W1302,W1303,W1304,W1305,W1306,W1307,W1401,W1402,W1501,W1503,W1645"
+PYLINT_ENABLE="--enable R0401,W0101,W0102,W0104,W0105,W0106,W0107,W0108,W0109,W0111,W0120,W0122,W0123,W0124,W0125,W0150,W0199,W0211,W0222,W0232,W0233,W0301,W0312,W0401,W0404,W0406,W0410,W0601,W0602,W0603,W0604,W0611,W0612,W0614,W0622,W0623,W0640,W0711,W1201,W1202,W1300,W1301,W1302,W1303,W1304,W1305,W1306,W1307,W1401,W1402,W1501,W1503,W1645"
 if [ "$AVOCADO_PARALLEL_LINT" ]; then
     LINT_CMD="$LINT_CMD --parallel=$AVOCADO_PARALLEL_LINT"
 fi