Add some blurb on correctly stopping the service w/mod_systemd. [skip ci]

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1873889 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/mod/mod_systemd.xml b/docs/manual/mod/mod_systemd.xml
index e24f3fed4954236faccd9ec82378e72245db8be3..e3e533bf8337d1b638633622c855faa332a81c62 100644 (file)
--- a/docs/manual/mod/mod_systemd.xml
+++ b/docs/manual/mod/mod_systemd.xml
@@ -47,13 +47,28 @@ After=network.target
 Type=notify
 ExecStart=/usr/local/apache2/bin/httpd -D FOREGROUND -k start
 ExecReload=/usr/local/apache2/bin/httpd -k graceful
-ExecStop=/usr/local/apache2/bin/httpd -k graceful-stop
+KillMode=mixed
 
 [Install]
 WantedBy=multi-user.target
     </pre>
     </example>
 
+   <p>Special attention should be given to how <code>ExecStop</code>
+   and/or <code>KillMode</code> are configured for the service.  If
+   configured, an <code>ExecStop</code> command should be a
+   <em>synchronous operation</em> which itself exits when the daemon
+   has terminated.  Running <code>httpd -k stop</code>
+   <em>asynchronously</em> initiates daemon termination, so does not
+   satisfy this condition.  The example above uses
+   <code>KillMode=mixed</code> so that systemd sends
+   <code>SIGTERM</code> to signal the parent process (and only the
+   parent) to shut down.  The entire process group is then sent
+   <code>SIGKILL</code> after <code>TimeoutStopSec</code> elapses, if
+   any processes are still running.  See <a
+   href="https://www.freedesktop.org/software/systemd/man/systemd.kill.html">systemd.kill(5)</a>
+   for more information.</p>
+    
    <p>This module does not provide support for Systemd socket activation.</p>
 
     <p><directive module="core">ExtendedStatus</directive> is