Hi list,
Watching the thread about startup script I thought of a question about

shutdown script. Is it necessary to shutdown certain services when

machine goes down? Like for example mysql, dovecot, clamav, amavis or

openvpn. I've never saw anybody do that. Lots of people on their

manuals, tutorials or posts writes how to start mysql, but none of then

writes a shutdown script. So maybe it is not so necessary? (But then

again, mysql is a database engine, and databases should be handle with

care).

any software which requires special shutdown handling ist busted.
all processes get a SIGTERM on shutdown. the ones that need to do

cleanup before they exit need to install a signal handler for that (and

in general they do).
--

Henning Brauer, hb@bsws.de, henning@openbsd.org

BS Web Services, http://bsws.de

Full-Service ISP - Secure Hosting, Mail and DNS Services

Dedicated Servers, Rootservers, Application Hosting - Hamburg & Amsterdam

Pardon the ignorant question.

By what method is shutdown then forced to wait until said processes have

cleaned up?  Is a response expected by shutdown from the daemon as a

result to sending SIGTERM?
Regards,

-Lars

None. rc.shutdown is for those processes with slow/important shutdown

that needs waiting for.
---

Lars Hansson

Ok.  So then rc.shutdown should be sure to poll the processes until they

are dead.

$ man rc.shutdown
Up to you. I shut down almost all daemons in it. Again, you can call

your own scripts, e.g:
echo -n ' mailman'

/usr/local/lib/mailman/bin/mailmanctl -q stop

sleep 30
echo -n ' mailgraph'

/usr/local/site/sbin/mailgraphctl stop > /dev/null
echo -n ' squid'

/usr/local/sbin/squid -k shutdown
echo -n ' dovecot'

pkill dovecot
echo -n ' apache'

apachectl stop
echo -n ' postfix'

/usr/local/site/sbin/postfixctl stop
echo -n ' viagrad'

su -m _viagrad  /usr/local/site/libexec/viagrad/viagrad stop
echo -n ' named'

rndc stop
echo '.'

Thanks, I will start using rc.shutdown more often :)

At least MySQL should have told you how to shutdown when installing it.
rc.shutdown(8)

Yes, it should have, but it haven't :) So I've got wondering :)
Julian Leyh wrote:
  On 14:48 Wed 19 Sep     , Tomas wrote:
    Hi list,
    Watching the thread about startup script I thought of a question about

    shutdown script. Is it necessary to shutdown certain services when machine

    goes down? Like for example mysql, dovecot, clamav, amavis or openvpn. I've

    never saw anybody do that. Lots of people on their manuals, tutorials or

    posts writes how to start mysql, but none of then writes a shutdown script.

    So maybe it is not so necessary? (But then again, mysql is a database

    engine, and databases should be handle with care).
  At least MySQL should have told you how to shutdown when installing it.
  rc.shutdown(8)

Very few, I'd wager. The only ones I bother with doing it for are

postgresql and mysql since it can take them a while to shut down

correctly and it can get messy if they're not.
---

Lars Hansson

And can I ask how do you do it? Because I don't want to write my mysql

password in rc.shutdown script.
Lars Hansson wrote:
  On 9/19/07, Tomas   <s.tomas@gmail.com>   wrote:
    Is it necessary to shutdown certain services when

    machine goes down?
  Very few, I'd wager. The only ones I bother with doing it for are

  postgresql and mysql since it can take them a while to shut down

  correctly and it can get messy if they're not.
  ---

  Lars Hansson

Try: /usr/local/share/mysql/mysql.server stop

Write a script /root/sbin/mysql-shutdown.sh with whatever you need in

it, & call that script from /etc/rc.shutdown
Only root can read it.
Or:
/usr/local/site/sbin/mysql-shutdown.sh
chmod it 0770, and chown it root:dba so that anyone in the dba group can

edit (passwd changes) and run the script.

Hi,

   yes, You are right - proper shutdown is important. This functionality

realizes script /etc/rc.shutdown fired during shutdown. I that place should

be commands for all services which require shutdown command.

I hope it is what You looking for ;) (sorry if it is to obvious true for

You). 
Best regards,

Artur

Yes it's obvious :) But I've got a little bit confused because I've seen

very few using it. But that's already my problem, isn't it? :) Thanks :)
Artur Litwinowicz wrote:
  Hi,

     yes, You are right - proper shutdown is important. This functionality

  realizes script /etc/rc.shutdown fired during shutdown. I that place should

  be commands for all services which require shutdown command.

  I hope it is what You looking for ;) (sorry if it is to obvious true for

  You). 
  Best regards,

  Artur
  On Wed, 19 Sep 2007 14:48:54 +0300, Tomas   <s.tomas@gmail.com>   wrote:
    Hi list,
    Watching the thread about startup script I thought of a question about

    shutdown script. Is it necessary to shutdown certain services when

    machine goes down? Like for example mysql, dovecot, clamav, amavis or

    openvpn. I've never saw anybody do that. Lots of people on their

    manuals, tutorials or posts writes how to start mysql, but none of then

    writes a shutdown script. So maybe it is not so necessary? (But then

    again, mysql is a database engine, and databases should be handle with

    care).

For most things, there's no need to worry at all.
From http://dev.mysql.com/doc/refman/5.0/en/server-shutdown.html,

mysql does a controlled shutdown when it receives SIGTERM.
Examining the code of halt(8) (in src/sbin/reboot), at normal shutdown

SIGTERM is sent to running processes, then a delay of 2 seconds before

a sync(2), then a delay of 3 seconds followed by SIGKILL to anything

still running.
So the question is, whether mysql has enough time to shut down

before it's killed. If you think it doesn't, you might like to add

something like 'pkill mysqld; sleep 10' to rc.shutdown. (No need

for some 'mysqladmin shutdown' which would mean listing a plain-

text password in the file).

Thank you so much Stuart for your reply :-)
I have a similar doubt.

What happens when I have a lot of windows open in my fvwm2 and I click

on my desktop and click "Exit Fvwm2" ?
Will all the X11 applications be shutdown decently?

Or is it better to type "halt" in an xterm?

What is the right way to shutdown a desktop?
Thank you so much once again :-)
Kind regards
Siju

There are some mechanisms to tell applications to shutdown when you

quit X (either by exiting the window manager, or more brutally with

Ctl+Alt+Backspace). They are a bit complex, and no all applications

handle the events they get. (and not all window managers implement the

same protocol).
For instance in my experience, firefox manages to remove its lock (in

~/.mozilla/firefox/hexstuff/) most of the time when I exit from X

(using Ctl+Alt+Backspace) without quitting it first.
But the safest way is to quit each application 1st, then exit the

window manager. Of course this is mainly important for applications

with pending changes like text editors, e-mail clients, or such.

xclock or xload don't care if they are terminated badly.

Stuart Henderson wrote:
  On 2007/09/19 14:48, Tomas wrote:
    Watching the thread about startup script I thought of a question about

    shutdown script. Is it necessary to shutdown certain services when machine

    goes down? Like for example mysql, dovecot, clamav, amavis or openvpn. I've

    never saw anybody do that.
  For most things, there's no need to worry at all.
  >From   http://dev.mysql.com/doc/refman/5.0/en/server-shutdown.html  ,

  mysql does a controlled shutdown when it receives SIGTERM.
  Examining the code of halt(8) (in src/sbin/reboot), at normal shutdown

  SIGTERM is sent to running processes, then a delay of 2 seconds before

  a sync(2), then a delay of 3 seconds followed by SIGKILL to anything

  still running.
  So the question is, whether mysql has enough time to shut down

  before it's killed. If you think it doesn't, you might like to add

  something like 'pkill mysqld; sleep 10' to rc.shutdown. (No need

  for some 'mysqladmin shutdown' which would mean listing a plain-

  text password in the file).
  That's an excelent idea. I will use 'pkill mysqld'. But instead of 'sleep 10' myabe it's better to check every second if mysqld.sock exists?

I would choose to limit the maximum time, in case mysqld deadlocks.
I think "pgrep mysqld" is a safer test than mysqld.sock (unless

you've read mysql code and determined that the control socket is

only removed after the tables have been flushed).

Something you should be aware of:

If there is insufficient space, MySQL will wait patiently for the

space to become available at which point it picks up like there

never was a problem.

Current behavior may be different. YMMV etc.

Surprising, but it can allow manipulation in low-disk situations.

I've no idea what happens to pending transactions (non-MyISAM databases)

I myself can't say if it's necessary, but it is probably good practice.
I do notice that OpenBSD does not use anything similar to System V

runlevels (which may or may not be good to avoid) but does provide

/etc/rc.shutdown:
Checking on my systems, I see that none of the packages that run daemons

use it, even the ones installed from the official packages and ports.

In fact, rc.shutdown appears completely empty.  Perhaps you have found

an error / oversight?
Regards,

-Lars

That's a good practice. There's no doubt about it. But like I said I've

seen very few people using it, in fact I saw it only once, shuting down

amavisd-new. But I don't think that's an error or oversight, that's our

ignorance :) And don't want to be ignorant :) So I've asked the question :)

postgresql-server uses it..
--

Przemyslaw Nowaczyk <p_nowaczyk@o2.pl>

CS student @ Poznan University of Technology

http://www.student.put.poznan.pl/~przemyslaw.nowaczyk/

Hi!
Probably most programs that need non-trivial cleanup handle SIGTERM

appropriately.
Kind regards,
Hannah.

Probably most of the programs does handle SIGTERM appropriately, but it

may be too little time for a program to clean itself before it receives

SIGKILL signal. For an example mysql. It needs to kill any connections to

it (and if any problem killing it, it should wait for some time and then

try again), sync data, remove socket (I don't know the exact order of

mysql shutdown task and I'm only guessing). And what if SIGKILL arrives

in the middle of the mysql shutdown tasks?
Hannah Schroeter wrote:
  Hi!
  On Wed, Sep 19, 2007 at 02:48:54PM +0300, Tomas wrote:
    Watching the thread about startup script I thought of a question about

    shutdown script. Is it necessary to shutdown certain services when

    machine goes down? Like for example mysql, dovecot, clamav, amavis or

    openvpn. I've never saw anybody do that. Lots of people on their

    manuals, tutorials or posts writes how to start mysql, but none of then

    writes a shutdown script. So maybe it is not so necessary? (But then

    again, mysql is a database engine, and databases should be handle with

    care).
  Probably most programs that need non-trivial cleanup handle SIGTERM

  appropriately.
  Kind regards,
  Hannah.