diff --git a/devstack/plugin.sh b/devstack/plugin.sh
index d1d2a080e..f96ebeb6a 100644
--- a/devstack/plugin.sh
+++ b/devstack/plugin.sh
@@ -22,6 +22,7 @@ IRONIC_INSPECTOR_COLLECTORS=${IRONIC_INSPECTOR_COLLECTORS:-default,logs,pci-devi
 IRONIC_INSPECTOR_RAMDISK_LOGDIR=${IRONIC_INSPECTOR_RAMDISK_LOGDIR:-$IRONIC_INSPECTOR_DATA_DIR/ramdisk-logs}
 IRONIC_INSPECTOR_ALWAYS_STORE_RAMDISK_LOGS=${IRONIC_INSPECTOR_ALWAYS_STORE_RAMDISK_LOGS:-True}
 IRONIC_INSPECTOR_TIMEOUT=${IRONIC_INSPECTOR_TIMEOUT:-600}
+IRONIC_INSPECTOR_CLEAN_UP_PERIOD=${IRONIC_INSPECTOR_CLEAN_UP_PERIOD:-}
 # These should not overlap with other ranges/networks
 IRONIC_INSPECTOR_INTERNAL_IP=${IRONIC_INSPECTOR_INTERNAL_IP:-172.24.42.254}
 IRONIC_INSPECTOR_INTERNAL_SUBNET_SIZE=${IRONIC_INSPECTOR_INTERNAL_SUBNET_SIZE:-24}
@@ -207,7 +208,9 @@ function configure_inspector {
         inspector_iniset processing node_not_found_hook "$IRONIC_INSPECTOR_NODE_NOT_FOUND_HOOK"
     fi
     inspector_iniset DEFAULT timeout $IRONIC_INSPECTOR_TIMEOUT
-
+    if [ -n "$IRONIC_INSPECTOR_CLEAN_UP_PERIOD" ]; then
+        inspector_iniset DEFAULT clean_up_period "$IRONIC_INSPECTOR_CLEAN_UP_PERIOD"
+    fi
     get_or_create_service "ironic-inspector" "baremetal-introspection" "Ironic Inspector baremetal introspection service"
     get_or_create_endpoint "baremetal-introspection" "$REGION_NAME" \
         "$IRONIC_INSPECTOR_URI" "$IRONIC_INSPECTOR_URI" "$IRONIC_INSPECTOR_URI"
diff --git a/ironic_inspector/main.py b/ironic_inspector/main.py
index 0ff3f6e93..ccc49e670 100644
--- a/ironic_inspector/main.py
+++ b/ironic_inspector/main.py
@@ -324,8 +324,6 @@ def handle_404(error):
     return error_response(error, code=404)
 
 
-@periodics.periodic(spacing=CONF.firewall.firewall_update_period,
-                    enabled=CONF.firewall.manage_firewall)
 def periodic_update():  # pragma: no cover
     try:
         firewall.update_filters()
@@ -333,7 +331,6 @@ def periodic_update():  # pragma: no cover
         LOG.exception(_LE('Periodic update of firewall rules failed'))
 
 
-@periodics.periodic(spacing=CONF.clean_up_period)
 def periodic_clean_up():  # pragma: no cover
     try:
         if node_cache.clean_up():
@@ -438,9 +435,17 @@ class Service(object):
         if CONF.firewall.manage_firewall:
             firewall.init()
 
+        periodic_update_ = periodics.periodic(
+            spacing=CONF.firewall.firewall_update_period,
+            enabled=CONF.firewall.manage_firewall
+        )(periodic_update)
+        periodic_clean_up_ = periodics.periodic(
+            spacing=CONF.clean_up_period
+        )(periodic_clean_up)
+
         self._periodics_worker = periodics.PeriodicWorker(
-            callables=[(periodic_update, None, None),
-                       (periodic_clean_up, None, None)],
+            callables=[(periodic_update_, None, None),
+                       (periodic_clean_up_, None, None)],
             executor_factory=periodics.ExistingExecutor(utils.executor()))
         utils.executor().submit(self._periodics_worker.start)
 
diff --git a/releasenotes/notes/fix-periodic-tasks-configuration-edd167f0146e60b5.yaml b/releasenotes/notes/fix-periodic-tasks-configuration-edd167f0146e60b5.yaml
new file mode 100644
index 000000000..2e3871d39
--- /dev/null
+++ b/releasenotes/notes/fix-periodic-tasks-configuration-edd167f0146e60b5.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    The configuration of the ``periodic_clean_up`` and ``periodic_update`` tasks
+    is now applied after the file ``inspector.conf`` is read