On 01/08/11 18:54, Volker Kuhlmann wrote:
> On Mon 01 Aug 2011 18:35:06 NZST +1200, C. Falconer wrote:
>> See if you can spot what's wrong with it.
>> /bin/rm -f $output0 2>&1 /dev/null
>
> Easy.
> 1) It'll delete /dev/null
Correct - one internet to Volker. I should have asked for replies off
list to give other people a chance :))
Did anyone notice it has to be running as root to delete /dev/null ?
Sadly it was.
And ssh simply refuses incoming connections if /dev/null doesn't exist.
And this particular box is inside a DC in another city, only manageable
by SSH (the ilo licence was deemed too spendy.)
In the end the local DC admin dropped by and did a quick mknod.
Interestingly, everything else was fine... mta, http server, virtual
machines, other monitoring daemons, everything else kept working.
A reboot of the box might have fixed it too, because udev would have
recreated /dev on boot.
Long-term mitigation against it happening again is a chunk in the
periodic sanity checker script.
if [ ! -c /dev/null ];
then
echo "/dev/null not found or not a character file, recreating"
/bin/mv /dev/null /dev/null.junk
/bin/mknod /dev/null c 1 3
/bin/chmod 666 /dev/null
/bin/sleep 5
/sbin/service sshd restart
fi
Any questions please ask
--
Craig Falconer
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