[lvs-users] where is connection?

Graeme Fowler graeme at graemef.net
Thu Aug 2 21:49:50 BST 2007


Hi Gerry

On Thu, 2007-08-02 at 16:24 -0400, Gerry Reno wrote:
> This is all LVS-DR and I admit I am no network expert. But I do think I 
> understand the basic concepts of how LVS functions. So here goes at some 
> basic information of my setup:
> 
> FIREWALLS: both MASTER and BACKUP are identical:

OK, good. That removes that as a problem.

> CONFIGS:
<snip>
> notify_master "/etc/keepalived/manage_ip_lvs_dr del"
> notify_backup "/etc/keepalived/manage_ip_lvs_dr add"
> notify_fault "/etc/keepalived/manage_ip_lvs_dr add"

This bit I have to say I'm puzzled about. Are your directors also the
realservers?

> NOTIFY SCRIPT ACTIONS:
> case del:
> rsh ALL_RS ip addr add 192.168.1.240/32 dev lo brd + scope host
> rsh ALL_RS echo "1" > /proc/sys/net/ipv4/conf/eth0/arp_ignore
> rsh ALL_RS echo "2" > /proc/sys/net/ipv4/conf/eth0/arp_announce
> rsh ALL_RS route del default
> rsh ALL_RS route add default gw 192.168.1.1
> 
> case add:
> ip addr add 192.168.1.240/32 dev lo brd + scope host

In the case you have two directors and N realservers, you *should not
need this script*. In the case that you have two directors which are
also realservers, you need something, but probably not this.

In the case of DR, the default gateway for the directors should not need
to change (unless I'm missing something about your topology), nor should
it for the realservers - it doesn't appear that you have a director
acting as gateway for the realservers, and the rsh seems to return a lot
of errors when trying to meddle with the default gateway. That probably
explains why they can't respond to clients.

> Please notice that the connection is showing to the BACKUP even though 
> the VIP/24 is on the MASTER eth0 interface. This is what I do not 
> understand. How is this possible?

Through the LVS Sync Daemon - the MASTER multicasts to all BACKUP state
servers, and they put entries in their connection tables just in case
they need to fail over.

> Anyway, is this enough information? Please let me know what else I can 
> provide.

An explanation of why your directors use rsh to frob the realservers'
network interfaces when they don't need to would be helpful, as that's
probably the cause.

Graeme





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