GitHub user zwoop opened a pull request:
https://github.com/apache/trafficserver/pull/1518
Ensure 'service trafficserver stopâ is synchronous under load on redhat
Currently the service trafficserver stop command on redhat might return
before ATS has exited.
This is not good as itâs often followed by a start, which then fails.
/etc/init.d/trafficserver does:
action "Stopping ${TC_NAME}:" killproc -p $TC_PIDFILE $TC_DAEMON
action "Stopping ${TM_NAME}:" killproc -p $TM_PIDFILE $TM_DAEMON
action "Stopping ${TS_NAME}:" killproc -p $TS_PIDFILE $TS_DAEMON
and killproc, as defined in /etc/rc.d/init.d/functions, with those
arguments essentially does this:
send SIGTERM
wait up to 3 seconds for it to exit
send SIGKILL
wait 0.1 seconds then return an exit status indicating if the process
still exists
A SIGKILL signal always causes the death of a process but itâs not
instantaneous. A process can take a long time to exit on a busy system for
assorted reasons, including flushing dirty buffers to disk.
So if the stop is immediately followed by a start, as it often is, the
start may fail with an error like âport 80 in useâ. This seems to be a
common cause of restart failures on busy systems and frustrating manual
hand-holding.
Contrast this with the behaviour that /etc/init.d/trafficserver uses when
run on Ubuntu⦠there itâll wait up to 35 seconds.
(It'll also use SIGQUIT instead of SIGTERM which seems odd).
This PR makes /etc/init.d/trafficserver more reliable, and consistent, on
redhat by adding `-d 35` to the killproc arguments so it'll wait for the
daemons to stop on redhat for about as long as it does in ubuntu. Not perfect,
but much better.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/zwoop/trafficserver TimsPatchSquashed
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/trafficserver/pull/1518.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1518
commit 432151695cbd2dcedfffcb1baed620d335154f15
Author: Tim Bunce
Date: 2017-02-28T18:14:15Z
Ensure 'service trafficserver stopâ is synchronous under load on redhat
Currently the service trafficserver stop command on redhat might return
before ATS has exited.
This is not good as itâs often followed by a start, which then fails.
/etc/init.d/trafficserver does:
action "Stopping ${TC_NAME}:" killproc -p $TC_PIDFILE $TC_DAEMON
action "Stopping ${TM_NAME}:" killproc -p $TM_PIDFILE $TM_DAEMON
action "Stopping ${TS_NAME}:" killproc -p $TS_PIDFILE $TS_DAEMON
and killproc, as defined in /etc/rc.d/init.d/functions, with those
arguments essentially does this:
send SIGTERM
wait up to 3 seconds for it to exit
send SIGKILL
wait 0.1 seconds then return an exit status indicating if the process
still exists
A SIGKILL signal always causes the death of a process but itâs not
instantaneous. A process can take a long time to exit on a busy system for
assorted reasons, including flushing dirty buffers to disk.
So if the stop is immediately followed by a start, as it often is, the
start may fail with an error like âport 80 in useâ. This seems to be a
common cause of restart failures on busy systems and frustrating manual
hand-holding.
Contrast this with the behaviour that /etc/init.d/trafficserver uses when
run on Ubuntu⦠there itâll wait up to 35 seconds.
(It'll also use SIGQUIT instead of SIGTERM which seems odd).
This PR makes /etc/init.d/trafficserver more reliable, and consistent, on
redhat by adding `-d 35` to the killproc arguments so it'll wait for the
daemons to stop on redhat for about as long as it does in ubuntu. Not perfect,
but much better.
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