man: Do not recommend to overlay files with sysext even if possible

While overlaying files with a sysext can be useful, it may lead to
unexpected problems depending on when a process got started and which
version of the file it gets.
Call out that overlaying files is possible but don't recommend to make
use of it.

diff --git a/man/systemd-sysext.xml b/man/systemd-sysext.xml
index 60ae4aa8bf0d5c1f4d55a95b4525dc1053abda81..d7f5d2f37f89e24098dac5590cb1c5be000ff82c 100644 (file)
--- a/man/systemd-sysext.xml
+++ b/man/systemd-sysext.xml
@@ -64,7 +64,7 @@
 
     <para>System extensions are supposed to be purely additive, i.e. they are supposed to include only files
     that do not exist in the underlying basic OS image. However, the underlying mechanism (overlayfs) also
-    allows removing files, but it is recommended not to make use of this.</para>
+    allows overlaying or removing files, but it is recommended not to make use of this.</para>
 
     <para>System extension images may be provided in the following formats:</para>