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On Thu, 2 Mar 2000, Antony Lee (HWL - Analyst Programmer, GISD) wrote:
> My situation is:
>
> I have setup two RedHat Linux 6.1, without any kernel patch, for LVSes. One
> is the
> primary LVS and the other is the backup LVS. Behind the two Linux, there are
> two
> NT IIS4 Web Servers.
>
> In each LVS, there are two network card installed. The eth0 is connected to
> a router which is connected to the Internet. The eth1 is connected to a
> private network
> which is the same segment as the two NT IIS4.
>
> The eth0 of the primary LVS is assigned an IP address 202.53.128.56
> The eth0 of the backup LVS is assigned an IP address 202.53.128.57
> The eth1 of the primary LVS is assigned an IP address 192.128.1.9
> The eth1 of the primary LVS is assigned an IP address 192.128.1.10
>
> In addition, both primary and backup LVS have enabled the IPV4 FORWARD and
> IPV4 DEFRAG. In the file /etc/rc.d/rc.local the following command was also
> added:
> ipchains -A -j MASQ 192.168.1.0/24 -d 0.0.0.0/0
>
>
> I use the piranha to configure the LVS so that the two LVS have a common
> IP address 202.53.128.58 in the eth0 as eth0:1. And have a IP address
> 192.128.1.1
> in the eth1 as eth1:1
>
> The pulse daemon is also automatically be run when the two LVSes were
> booted.
>
> In my configuration, the Internet clients can still access to our Web server
> with one of
> the NT was disconnected from the LVS. The backup LVS --CAN AUTOMATICALLY--
> take up the role of the primary LVS when the primary LVS is shutted down or
> disconnected
> from the backup LVS. However, I found that all the NT Web Servers cannot
> reach the backup
> LVS through the common IP address 192.128.1.1, and all the Internet clients
> stalled to
> connect to our web servers.
>
> Later, I found that the problem may due to the ARP caching in the Web
> Servers and router.
> I tried to limit the ARP cache time to 5 seconds in the NT servers and half
> of the problem has solved
> , i.e. the NT Web servers can reach the backup LVS through the common IP
> address 192.128.1.1
> when the primary LVS was down. However, it is still cannot be connected
> through the Internet clients
> when the LVS failover occur.
>
I just tried two LVS boxes with piranha 0.3.15. When the primary LVS stops
or fails, the backup will take over and send out two Gratuitous Arp
packets for the VIP and the NAT router IP respectively, which should clean
the ARP caching in both the web servers and the external router.
After the LVS failover occurs, the established connections from the
clients will be lost in the current version, and the clients need to
re-connection the LVS.
Cheers,
Wensong
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