Host automatically up and down

Saturday, November 4. 2006

Host automatically up and down

For the usage of a local backup host, I defined the following scenario, which could also be used for a printer server or any other type of host, which shouldn’t run 24/7, but:

The host should be able to be woken up manually by a special signal on the LAN, i.e., it should be capable of WOL. (This is only a hardware issue)
If it is woken up, it should run at least for 30 minutes before trying to shutdown again.
It shouldn’t shut down while certain processes are running, such as a backup, i.e., it should be capable of a shutdown-lock. If the lock is removed, it might shutdown.
The host shouldn’t shut down as long as a certain client, e.g. a backup client, is (still) up and running (pingable)
If the criteria above aren’t hurt, the host should finally shut down.

And here’s the shell-script which implements the above. It’s enough to have it run every five minutes. The “echoes” are only interesting for debugging purposes.

#!/bin/bash

lockfile=/etc/lock_shutdown
upclient=fourier
min_upminutes=30

# If shutdown locked, keep running
if [ -f $lockfile ]; then
echo “Locked”
exit 0
fi

# If client is still there, keep running
if ping -t10 -c1 $upclient &>/dev/null; then
echo “$upclient still there”
exit 0
fi

# If we are up long enough ...
cur_secs=$(cut -d. -f1 /proc/uptime)
if [ $cur_secs -lt $[$min_upminutes*60] ]; then
echo “Not up long enough”
exit 0
fi

# ... then shut down!
echo “Shutting down”
/sbin/shutdown -h 1 &

Posted by Stephan Paukner in GNU/Linux at 19:05 | Comments (0) | Trackbacks (0)

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