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Posted to cvs@httpd.apache.org by co...@apache.org on 2005/08/26 18:09:58 UTC
svn commit: r240270 - in /httpd/httpd/trunk: CHANGES
server/mpm/prefork/mpm.h server/mpm/prefork/prefork.c
Author: colm
Date: Fri Aug 26 09:09:54 2005
New Revision: 240270
URL: http://svn.apache.org/viewcvs?rev=240270&view=rev
Log:
Implement a "graceful-stop" for the prefork MPM (might aswell do the hard one
first).
General approach is to send SIGUSR1 to all children (which will de-listen, and
exit when finished), and to gather all children as they exit.
We don't use a sleep(timeout) for the timeout implementation, because this
would lead to a rut of defunct children until the timeout had expired.
set_graceful_shutdown stolen from Ken Coar. See <3E...@Golux.Com>
(28 Mar 2003).
Modified:
httpd/httpd/trunk/CHANGES
httpd/httpd/trunk/server/mpm/prefork/mpm.h
httpd/httpd/trunk/server/mpm/prefork/prefork.c
Modified: httpd/httpd/trunk/CHANGES
URL: http://svn.apache.org/viewcvs/httpd/httpd/trunk/CHANGES?rev=240270&r1=240269&r2=240270&view=diff
==============================================================================
--- httpd/httpd/trunk/CHANGES [utf-8] (original)
+++ httpd/httpd/trunk/CHANGES [utf-8] Fri Aug 26 09:09:54 2005
@@ -2,6 +2,10 @@
Changes with Apache 2.3.0
[Remove entries to the current 2.0 and 2.2 section below, when backported]
+ *) prefork: Support a graceful-stop procedure. Server will wait until
+ existing requests are finished or until "GracefulShutdownTimeout"
+ before exiting. [Colm MacCarthaigh, Ken Coar]
+
*) mod_cgid: Append .PID to the script socket filename and remove the
script socket on exit. [Colm MacCarthaigh]
Modified: httpd/httpd/trunk/server/mpm/prefork/mpm.h
URL: http://svn.apache.org/viewcvs/httpd/httpd/trunk/server/mpm/prefork/mpm.h?rev=240270&r1=240269&r2=240270&view=diff
==============================================================================
--- httpd/httpd/trunk/server/mpm/prefork/mpm.h (original)
+++ httpd/httpd/trunk/server/mpm/prefork/mpm.h Fri Aug 26 09:09:54 2005
@@ -39,6 +39,7 @@
#define AP_MPM_WANT_SET_MAX_MEM_FREE
#define AP_MPM_WANT_FATAL_SIGNAL_HANDLER
#define AP_MPM_DISABLE_NAGLE_ACCEPTED_SOCK
+#define AP_MPM_SUPPORTS_GRACEFUL_STOP
#define AP_MPM_USES_POD 1
#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
Modified: httpd/httpd/trunk/server/mpm/prefork/prefork.c
URL: http://svn.apache.org/viewcvs/httpd/httpd/trunk/server/mpm/prefork/prefork.c?rev=240270&r1=240269&r2=240270&view=diff
==============================================================================
--- httpd/httpd/trunk/server/mpm/prefork/prefork.c (original)
+++ httpd/httpd/trunk/server/mpm/prefork/prefork.c Fri Aug 26 09:09:54 2005
@@ -96,6 +96,7 @@
static int ap_daemons_min_free=0;
static int ap_daemons_max_free=0;
static int ap_daemons_limit=0; /* MaxClients */
+static int graceful_shutdown_timeout = 0;
static int server_limit = DEFAULT_SERVER_LIMIT;
static int first_server_limit;
static int changed_limit_at_restart;
@@ -334,6 +335,9 @@
static void stop_listening(int sig)
{
ap_close_listeners();
+
+ /* For a graceful stop, we want the child to exit when done */
+ die_now = 1;
}
/* volatile just in case */
@@ -351,6 +355,7 @@
return;
}
shutdown_pending = 1;
+ is_graceful = (sig == AP_SIG_GRACEFUL_STOP);
}
/* restart() is the signal handler for SIGHUP and AP_SIG_GRACEFUL
@@ -383,6 +388,11 @@
sa.sa_handler = sig_term;
if (sigaction(SIGTERM, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGTERM)");
+#ifdef AP_SIG_GRACEFUL_STOP
+ if (sigaction(AP_SIG_GRACEFUL_STOP, &sa, NULL) < 0)
+ ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+ "sigaction(" AP_SIG_GRACEFUL_STOP_STRING ")");
+#endif
#ifdef SIGINT
if (sigaction(SIGINT, &sa, NULL) < 0)
ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGINT)");
@@ -430,6 +440,9 @@
#ifdef AP_SIG_GRACEFUL
apr_signal(AP_SIG_GRACEFUL, restart);
#endif /* AP_SIG_GRACEFUL */
+#ifdef AP_SIG_GRACEFUL_STOP
+ apr_signal(AP_SIG_GRACEFUL_STOP, sig_term);
+#endif /* AP_SIG_GRACEFUL */
#ifdef SIGPIPE
apr_signal(SIGPIPE, SIG_IGN);
#endif /* SIGPIPE */
@@ -1074,8 +1087,8 @@
mpm_state = AP_MPMQ_STOPPING;
- if (shutdown_pending) {
- /* Time to gracefully shut down:
+ if (shutdown_pending && !is_graceful) {
+ /* Time to shut down:
* Kill child processes, tell them to call child_exit, etc...
*/
if (unixd_killpg(getpgrp(), SIGTERM) < 0) {
@@ -1096,6 +1109,103 @@
ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
"caught SIGTERM, shutting down");
+
+ return 1;
+ } else if (shutdown_pending) {
+ /* Time to perform a graceful shut down:
+ * Reap the inactive children, and ask the active ones
+ * to close their listeners, then wait until they are
+ * all done to exit.
+ */
+ int active_children;
+ apr_exit_why_e exitwhy;
+ int status;
+ int child_slot;
+ apr_proc_t pid;
+ apr_time_t cutoff;
+
+ /* Stop listening */
+ ap_close_listeners();
+
+ /* kill off the idle ones */
+ ap_mpm_pod_killpg(pod, ap_max_daemons_limit);
+
+ /* Send SIGUSR1 to the active children */
+ active_children = 0;
+ for (index = 0; index < ap_daemons_limit; ++index) {
+ if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) {
+ ap_scoreboard_image->servers[index][0].status = SERVER_GRACEFUL;
+ /* Ask each child to close its listeners. */
+ kill(ap_scoreboard_image->parent[index].pid, AP_SIG_GRACEFUL);
+ active_children++;
+ }
+ }
+
+ /* Allow each child which actually finished to exit */
+ for (; active_children; active_children--) {
+ ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
+
+ if (pid.pid != -1) {
+ child_slot = find_child_by_pid(&pid);
+ if (child_slot >= 0) {
+ (void) ap_update_child_status_from_indexes(child_slot, 0,
+ SERVER_DEAD, (request_rec *) NULL);
+ }
+ }
+ }
+
+ /* cleanup pid file */
+ {
+ const char *pidfile = NULL;
+ pidfile = ap_server_root_relative (pconf, ap_pid_fname);
+ if ( pidfile != NULL && unlink(pidfile) == 0)
+ ap_log_error(APLOG_MARK, APLOG_INFO,
+ 0, ap_server_conf,
+ "removed PID file %s (pid=%ld)",
+ pidfile, (long)getpid());
+ }
+
+ ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+ "caught " AP_SIG_GRACEFUL_STOP_STRING ", shutting down gracefully");
+
+ if (graceful_shutdown_timeout) {
+ cutoff = apr_time_now() +
+ apr_time_from_sec(graceful_shutdown_timeout);
+ }
+
+ /* Don't really exit until each child has finished */
+ shutdown_pending = 0;
+ do {
+ active_children = 0;
+ for (index = 0; index < ap_daemons_limit; ++index) {
+ if (ap_scoreboard_image->servers[index][0].status != SERVER_DEAD) {
+ if (kill(ap_scoreboard_image->parent[index].pid, 0) == 0) {
+ active_children++;
+ }
+ }
+ }
+
+ for (index = 0; index < active_children; ++index) {
+ /* Gather any now finished children */
+ ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
+
+ if (pid.pid != -1) {
+ child_slot = find_child_by_pid(&pid);
+ if (child_slot >= 0) {
+ (void) ap_update_child_status_from_indexes(child_slot,
+ 0, SERVER_DEAD, (request_rec *) NULL);
+ }
+ }
+ }
+ } while (!shutdown_pending && active_children &&
+ (!graceful_shutdown_timeout || apr_time_now() < cutoff));
+
+ /* We might be here because we received SIGTERM, either
+ * way, try and make sure that all of our processes are
+ * really dead.
+ */
+ unixd_killpg(getpgrp(), SIGTERM);
+
return 1;
}
@@ -1363,6 +1473,16 @@
return NULL;
}
+static const char *set_graceful_shutdown(cmd_parms *cmd, void *dummy, const char *arg)
+{
+ const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+ if (err != NULL) {
+ return err;
+ }
+ graceful_shutdown_timeout = atoi(arg);
+ return NULL;
+}
+
static const command_rec prefork_cmds[] = {
UNIX_DAEMON_COMMANDS,
LISTEN_COMMANDS,
@@ -1376,6 +1496,9 @@
"Maximum number of children alive at the same time"),
AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
"Maximum value of MaxClients for this run of Apache"),
+AP_INIT_TAKE1("GracefulShutdownTimeout", set_graceful_shutdown, NULL, RSRC_CONF,
+ "Time in seconds to wait for child processes to complete "
+ "transactions during shutdown"),
{ NULL }
};
Re: svn commit: r240270 - in /httpd/httpd/trunk: CHANGES server/mpm/prefork/mpm.h server/mpm/prefork/prefork.c
Posted by Colm MacCarthaigh <co...@stdlib.net>.
I decided to do prefork first, since it seems the more complicated out
of the MPM's to stop gracefully. I've tested locally, using
#!/bin/sh
echo "Content-type: text/plain"
echo
while true; do
sleep 1
date
done
as my ultra-sophisticated long-lived download, however I would be amazed
if running two instances of httpd concurrently does not break some
things (esp third party modules which use some kind of lockfile or
on-disk state). So, heads up there on any trunk-runners.
I'm going to add yet more documentation to stopping.xml, to describe
those kind of issues.
On Fri, Aug 26, 2005 at 04:09:58PM -0000, colm@apache.org wrote:
> Author: colm
> Date: Fri Aug 26 09:09:54 2005
> New Revision: 240270
>
> URL: http://svn.apache.org/viewcvs?rev=240270&view=rev
> Log:
>
> Implement a "graceful-stop" for the prefork MPM (might aswell do the hard one
> first).
>
> General approach is to send SIGUSR1 to all children (which will de-listen, and
> exit when finished), and to gather all children as they exit.
>
> We don't use a sleep(timeout) for the timeout implementation, because this
> would lead to a rut of defunct children until the timeout had expired.
>
> set_graceful_shutdown stolen from Ken Coar. See <3E...@Golux.Com>
> (28 Mar 2003).
>
>
> Modified:
> httpd/httpd/trunk/CHANGES
> httpd/httpd/trunk/server/mpm/prefork/mpm.h
> httpd/httpd/trunk/server/mpm/prefork/prefork.c
--
Colm MacCárthaigh Public Key: colm+pgp@stdlib.net