Re: Problems with keepalived

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: Problems with keepalived
From: Dr A V Le Blanc <LeBlanc@xxxxxxxxx>
Date: Thu, 29 Jun 2006 09:03:27 +0100
Many thanks to Graeme Fowler, whose suggestions led to the solution.

On Wed, Jun 28, 2006 at 04:02:14PM +0100, Graeme Fowler wrote:
> Decomplicate things a bit:
> 1. Remove the VRRP authentication completely (if you feel you can).

I wasn't aware that this worked.

> 2. You only have a single VRRP instance; you don't need a 
> vrrp_sync_group. Comment it out.

And I wasn't aware that this was possible either.

> Start the one assumed to be MASTER.
> On the server assumed to be BACKUP, use tcpdump to make sure you can see 
> the announcements - "tcpdump -qn net" should see you on your 
> way with this. If you can, make sure that you don't have iptables rules 
> sitting there getting in the way of them.

I was unaware of this; it showed that there were two machines using
the same vrid, and the other was of course my real server -- the
servers I am experimenting with are test servers.  Hence:

> Also, as you don't describe your environment, make sure nobody else on 
> the same network is doing VRRP. If they are, think about your 
> inter-server communication by considering putting the announcements on a 
> private or protected network instead.

Perceptive.  I changed the vrid to another number and it worked fine.

On Wed, Jun 28, 2006 at 12:43:48PM -0700, Brad Dameron wrote:
> Your virtual_router_id on the backup needs to be incremented. 

When I follow this advice, it stops working.  Apparently the
virtual_router_id needs to be the same on both machines.  So, the
failover is now working, with about a one second interval.
I presume the advert_int could be used to adjust this -- 1 second
is ideal for me in any case.

Many thanks for your help in solving this problem.

     -- Owen

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