diff --git a/requirements-test.txt b/requirements-test.txt
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -4,3 +4,4 @@
 types-click
 types-pyyaml
 types-requests
+types-filelock
diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,4 @@
 beautifulsoup4
 launchpadlib
 tenacity
+filelock
diff --git a/swh/lister/opam/lister.py b/swh/lister/opam/lister.py
--- a/swh/lister/opam/lister.py
+++ b/swh/lister/opam/lister.py
@@ -9,6 +9,8 @@
 from subprocess import PIPE, Popen, call
 from typing import Any, Dict, Iterator, Optional
 
+from filelock import FileLock, Timeout
+
 from swh.lister.pattern import StatelessLister
 from swh.scheduler.interface import SchedulerInterface
 from swh.scheduler.model import ListedOrigin
@@ -137,5 +139,13 @@
             instance,
             url,
         ]
-    # Actually execute the command
-    call(command, env=env)
+    try:
+        lock_name = "swh-lister-opam-maintenance.txt"
+        lock_path = os.path.join(opam_root, lock_name)
+        with FileLock(lock_path).acquire(timeout=10):
+            open(lock_path, "a").write("maintenance update")
+            # Actually execute the command
+            call(command, env=env)
+    except Timeout:
+        logger.warning("Another instance of this application currently holds the lock.")
+        raise