[Linux-cluster] LVS, not so fun today...

[David Brieck Jr.]

On 11/9/06, isplist at logicore.net <isplist at logicore.net> wrote:
> > Alright, so what does the ifconfig look like for one of the real
> > servers?
>
> Here's the output of the first server, cweb92.
>
> eth0      Link encap:Ethernet  HWaddr 00:20:94:10:3B:13
>           inet addr:192.168.1.92  Bcast:192.168.1.255  Mask:255.255.255.0
>           inet6 addr: fe80::220:94ff:fe10:3b13/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:1525827 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:189047 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:108127316 (103.1 MiB)  TX bytes:34679304 (33.0 MiB)
>
> lo        Link encap:Local Loopback
>           inet addr:127.0.0.1  Mask:255.0.0.0
>           inet6 addr: ::1/128 Scope:Host
>           UP LOOPBACK RUNNING  MTU:16436  Metric:1
>           RX packets:205 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:205 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:0
>           RX bytes:13204 (12.8 KiB)  TX bytes:13204 (12.8 KiB)
>
> >What method are you using to make sure the real server
> >responds to the VIP requests?
>
> Ping and arping from other servers on the network. 192.168.1.150 seems to
> respond to all servers.
>
> > For me, I have the VIP on the loopback adapter and use an arptable
> > rule to make sure it doesn't respond to arp requests. You need to make
> > sure apache is listening on the VIP, not it's actual IP address.
>
> Right but at this point, I've confused myself with what method to use. What
> method do you use or what commands do you run on your real servers to set up
> the IP?
>
> My VIP is 192.168.1.150. The real IP on the first web server is 192.168.1.92,
> then 93 and 94 on the next servers. I suspect if web alone is this
> complicated, that trying to set up my mail services are going to be murder :).
>
> Mike
>

On each real server you need to have to VIP setup on lo:0 (or 1,2,3 if
needed). It should have a netmask of 255.255.255.255.

Something like:

cat /etc/sysconfig/network-scripts/ifcfg-lo:0
NETMASK=255.255.255.255
MTU=""
BOOTPROTO=none
BROADCAST=192.168.1.255
ONPARENT=yes
IPADDR=192.168.1.150
NETWORK=192.168.1.1
ONBOOT=yes
DEVICE=lo:0

Then, add the following to the end of /etc/rc.local:

# make sure we don't respond to arp requests for the mysql cluster
arptables -A IN -d 192.168.1.150 -j DROP

this will fix any ARP problems.

So, once you do the above, just run

ifup lo:0 && arptables -A IN -d 192.168.1.150 -j DROP

You need to do this on all of the servers which need to respond to the
VIP. Then, in your apache config file make sure apache is listening on
the VIP NOT 192.168.1.92, 93, or 94. Make any adjustments then restart
apache.