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Hi,
I run into the same problems some time ago, so I wrote a little script,
which tests
the server first with an port connect (port 22 / ssh), but when the
connect fails, or the script
guesses it has allready taken the IP, it uses arping to check if the IP
is allive.
The -D switch of arping is very usefull in that case :-)
OK, now backup releases the IP from the director, but there are still
some arp-caches which uses the entry
from the backup.
so I added following lines to end of the ip_stop functoin of IPaddr:
ETH=`${FINDIF} ${FULLIP} |cut -f1`
if ! `${ARPING} -D ${BASEIP} -I ${ETH} -c 1 -w 1 -q` ; then
MACADDR=`${ARPING} -D ${BASEIP} -I ${ETH} -w 1 -c 1|grep Unicast|cut
-d "[" -f 2- | cut -d "]" -f1`
for j in 1 2 3 4
do
$SENDARP ${ETH} ${BASEIP} ${MACADDR} ${BASEIP} ffffffffffff
sleep 1
done
fi
now the backup broadcasts the mac-address from the master into the
network.
the paths of findif, arping and sendarp must also be added to IPaddr.
--
Chris
Miri Groentman wrote:
>
> In ?High Availability?
> (<http://www.linuxvirtualserver.org/HighAvailability.html>) it is mentioned
> that the backup server activates Fake and fakes the server?s ip, and when
> the server (LinuxDirector) is up again, it releases the ip it was faking. My
> question is: Can there be a situation in which both LinuxDirector and the
> backup have the same ip address at a given moment ? (exaples to such a
> situation: A. In case a crucial demon on LinuxDirector is down, but the
> LinuxDirector itself is up and can respond to ARP. In such a case the backup
> might take over, faking LinuxDirector?s ip because of the crucial demon
> that?s down. Both LinuxDirector and the backup might respond to the an ARP
> with the same ip address.
> B. In case the LinuxDirector has recovered after a crash, and it is up
> again, but the backup hasn?t learned about it yet, again, both LinuxDirector
> and the backup have the same ip. What happens to a packet directed at the
> LinuxDirector arriving at such time? )
>
> Case b :
> LinuxDirector backup
> | |
> | |
> down -- | |
> | |
> | |--fakes ip
> | |
> | |
> up again -- | | |
> | | | <--- what what
> happens here?
> | | |
> | |-- learn that LinuxDirector
> is up and stop faking
>
> thanks
> -Mrii
>
>
>
>
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