Add caution in system+semaphore

jderusse · jderusse · commit c52f50c1aa7e · 2020-02-03T21:32:16.000+01:00
diff --git a/components/lock.rst b/components/lock.rst
@@ -631,6 +631,14 @@ can be two running containers in parallel.
     concurrent process on a new machine, check that other process are stopped
     on the old one.
 
+.. caution::
+
+    When runing on systemd with option ``RemoveIPC=yes``  (default value for
+    non-system user), locks are deleted by systemd, when the user logs out,
+    or a cron job ends. This is a well known `issue reported in systemd`_.
+    Check that process is ran with a system user (UID<1000), or set the
+    option ``RemoveIPC=off`` in ``/etc/systemd/logind.conf``.
+
 ZookeeperStore
 ~~~~~~~~~~~~~~
 
@@ -670,3 +678,4 @@ are still running.
 .. _`Doctrine DBAL Connection`: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Connection.php
 .. _`Data Source Name (DSN)`: https://en.wikipedia.org/wiki/Data_source_name
 .. _`ZooKeeper`: https://zookeeper.apache.org/
+.. _`issue reported in systemd`: https://github.com/systemd/systemd/issues/2039
