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authorLaurent Bercot <ska-skaware@skarnet.org>2018-04-05 09:42:37 +0000
committerLaurent Bercot <ska-skaware@skarnet.org>2018-04-05 09:42:37 +0000
commitae97e8065a0e3be60d16c0d9e158afc697aa94e5 (patch)
tree00e44d6ab2a4099d0b21db69688747876cecb0b3 /doc/s6-svscan.html
parentdfe97bb01666ffc2af8029de06aa6ae5ff473a2a (diff)
downloads6-ae97e8065a0e3be60d16c0d9e158afc697aa94e5.tar.xz
Add note about SIGINT in s6-svscan and s6-supervise doc
Diffstat (limited to 'doc/s6-svscan.html')
-rw-r--r--doc/s6-svscan.html15
1 files changed, 14 insertions, 1 deletions
diff --git a/doc/s6-svscan.html b/doc/s6-svscan.html
index 7649abd..4bb943b 100644
--- a/doc/s6-svscan.html
+++ b/doc/s6-svscan.html
@@ -200,7 +200,7 @@ uses <a href="s6-svscanctl.html">s6-svscanctl -n</a>), but inactive
s6-supervise processes will not be restarted if they die.
</p>
-<h2> Implementation notes </h2>
+<h2> Notes </h2>
<ul>
<li> s6-svscan is designed to run until the machine is shut down. It is
@@ -220,6 +220,19 @@ to guarantee that s6-svscan does not use heap memory at all.</small> </li>
<li> When run with the <tt>-t0</tt> option, s6-svscan <em>never polls</em>,
it only wakes up on notifications, just like s6-supervise. The s6 supervision
tree can be used in energy-critical environments. </li>
+ <li> The supervision tree (i.e. the tree of processes made of s6-svscan and
+all its scions) is not supposed to have a controlling terminal; s6-svscan
+generally is either process 1 or a child of process 1, not something that is
+launched from a terminal. If you run s6-svscan from an interactive shell, be
+warned that typing ^C in the controlling terminal (which sends a SIGINT to
+all processes in the foreground process group in the terminal) will terminate
+the supervision tree, but not the supervised processes - so, the supervised
+processes will keep running as orphans. This is by design: supervised
+processes should be as resilient as possible, even when their supervisors
+die. However, if you want to launch s6-svscan from an interactive shell and
+need your services to die with the supervision tree when you ^C it, you can
+obtain this behaviour by creating <tt>./nosetsid</tt> files in every
+<a href="servicedir.html">service directory</a>. </li>
</ul>
</body>