[lvs-users] localnode issue

Thomas Pedoussaut thomas at pedoussaut.com
Fri Aug 29 11:27:26 BST 2008


Vishwanath T. K. wrote:
> Hi All,
>
> I have configured the LVS in local node. The configuration included two
> nodes (director+real server)
>
> VIP: 192.168.2.200
>
> Node configuration:
>
> node1:
>          ifconfig lo:0 192.168.2.200 netmask 255.255.255.255 broadcast
> 192.168.2.200 up
>          eth0: 192.168.2.50/24 gateway 192.168.2.254, dev eth0
>          HTTP service listening on all interfaces.
>
> IPVSADM:
>          ipvsadm -A -t 192.168.2.200:80 -s rr
>          ipvsadm -a -t 192.168.2.200:80 -r 192.168.2.50:80
>          ipvsadm -a -t 192.168.2.200:80 -r 192.168.2.51:80 -g
>
>
> node2:
>          eth0: 192.168.2.51/24 gateway 192.168.2.254, dev eth0
>          HTTP service listening on all interfaces.
>
> Client IP: 192.168.2.1
>
> Now the problem i am having
>
> When i access 192.168.2.200 from the client, and when the service request is
> sent to the node2 nothing happens, while then the service request is
> forwarded to 192.168.2.50 (real IP on node1) the web pages are served.
>
> IPVSADM - connection output
>
> [root at node1 ~]# ipvsadm -lnc
> IPVS connection entries
> pro expire state       source             virtual            destination
> TCP 01:57  FIN_WAIT    192.168.2.1:50307  192.168.2.200:80   192.168.2.50:80
> TCP 00:52  SYN_RECV    192.168.2.1:50294  192.168.2.200:80   192.168.2.51:80
>
> Why the second node is not serving any request ? Is there
> setup/configuration left on the node2 ?
>   
 From your config I take you are using direct routing.
Your node 2 doesn't know it has to handle traffic for the VIP, so it 
silently drops packets arriving.
You need to configure the VIP as an alias of lo on that node as well ( 
and play with the arp config to avoid announcing that IP on the network.
Add that in /etc/sysctl.conf
net.ipv4.conf.eth0.arp_ignore = 1
net.ipv4.conf.eth0.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2

Reading the doc http://www.linuxvirtualserver.org/VS-DRouting.html helps 
a lot as well.




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