What breed of UPS are you using?
If it's an APC there is apcupsd which is a good tool... I use it at
home to monitor one ups and shutdown two boxes, and also on my
workstation. We also use it at work on all our gear, both windows and
Linux with a Linux master. It's also got a cutesy web admin screen
thingy to monitor activity.
Even if you don't have an APC ups you can monitor 'dumb' signaling UPS's
with it on a tty port.
Cheers, Me.
Rex Johnston wrote:
Hi all,
Had a fun time yesterday afternoon trying to make one machine
supervise the shutdown of another.
The situation is this...
UPS, serial connection to server A, has server A and server B
connected to power outlets.
The UPS in question will only talk to OpenUPSmartd, which is a single
machine daemon, and the
documentation suggests that it is compatible with pretty much
everything, however, the site
suggested (www.ups-software-download.com) has a pretty woeful
selection of software, and i
didn't like the look of the linux version.
Anyway, OpenUPSmartd is the software you want. Missing is a startup
script...
[EMAIL PROTECTED]:~$ cat /etc/init.d/openupsmartd
#!/bin/sh
PATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin
set -e
case "$1" in
start)
test -x /usr/local/bin/openupsmartd || exit 0
nohup /usr/local/bin/openupsmartd > /var/log/openupsmartd.out 2>&1 &
;;
stop)
killall openupsmartd
;;
esac
You'll know it's working fine when you see this in syslog
Sep 6 12:41:59 serverA openupsmartd: IN:234.40V, FAULT:233.90V,
OUT:231.30V, LOAD:13.00% ^I^I^I INFREQ:50.00hz, BATT:27.70V, TEMP:25.
00C, FLAGS 00001001 ^I^I^I ( FLAG_BEEPER FLAG_STANDBY )
Now, this has to control 2 machines, not just this one...
link the configuration file from where it installs it to where it
expects it
lrwxrwxrwx 1 root root 31 Aug 15 13:44
/etc/openupsmart.conf -> /usr/local/etc/openupsmart.conf
and edit thus...
use_syslog=y
shutdown_command="/root/scripts/start_shutdown"
restore_command="/root/scripts/stop_shutdown"
serverA:~/scripts# cat start_shutdown
#!/bin/bash
nohup /sbin/shutdown -h +4 < /dev/null > /dev/null 2>&1 &
ssh [EMAIL PROTECTED] /root/scripts/start_shutdown &
serverA:~/scripts# cat stop_shutdown
#!/bin/bash
nohup /sbin/shutdown -c < /dev/null > /dev/null 2>&1 &
ssh [EMAIL PROTECTED] /root/scripts/stop_shutdown &
Now you need to set up an rsa key on serverB so that serverA can
connect via ssh without a password.
There are numerous places this is described, i set up 2 accounts,
"shutdown" and "noshutdown",
the first to initiate the shutdown of serverB, the second to stop it
when/if the power is restored.
It's easier to grep for events in the log file this way.
Once done, you need these on serverB
serverB:~/scripts# cat start_shutdown
#!/bin/bash
nohup /sbin/shutdown -h +3 &
serverB:~/scripts# cat stop_shutdown
#!/bin/bash
nohup /sbin/shutdown -c &
Now create a shutdown group, make sure that shutdown (&noshutdown) are
by default that group,
[EMAIL PROTECTED]:~$ id
uid=1130(shutdown) gid=1044(shutdown) groups=1044(shutdown)
and alter the permissions on /sbin/shutdown so it looks like this...
[EMAIL PROTECTED]:~$ ls -l /sbin/shutdown
-rwsr-x--- 1 root shutdown 17388 Sep 5 15:00 /sbin/shutdown
(that's 4750, NOT 4755)
make sure that only shutdown (&noshutdown) are in this group.
Now comes the tricky bit.
When shutdown is called with a delay, it creates a file called
/etc/nologin which contains
the text displayed before the ssh daemon kicks you off. If you have a
later version of sysvinit,
you can modify /etc/pam.d/ssh to stop this behaviour. Earlier
versions of sshd have this built in,
and non-defeatable. The upshot of this nasty behaviour is that once
shutdown is called on serverB,
serverA can't log back in to stop this shutdown when/if power is
restored.
What to do?
I used apt-src to install sysvinit tools and edited
src/shutdown.c like this...
/* Give warnings on regular intervals and finally shutdown. */
if (wt < 15 && !needwarning(wt)) warn(wt);
while(wt) {
if (wt <= 5 && !didnolog) {
// donologin(wt);
didnolog++;
}
if (needwarning(wt)) warn(wt);
hardsleep(60);
wt--;
}
before installing.
Cheers, Rex
