[Pacemaker] Understanding virtual IP migration

[Ken Gaillot]

On 07/23/2014 12:15 AM, Arjun Pandey wrote:
> I am using virtual IP resource on  a 2 node (Active-Passive) cluster.
> I was testing the migration of IP address. Moving the link down moves
> the IP over to the other node. However if i bring interface up on the
> node the VIP is still associated with this interface. Shouldn't we
> have removed this when we decided to migrate the IP in the first place
> ?
>
> Also on a related note plugging out the cable, doesn't lead to IP
> migration. I checked the IPAddr monitor logic which simply checks if
> the address is still associated with the interface. However shouldn't
> we be checking link state as well using ethtool.

Hello Arjun,

Pacemaker can certainly do what you want, but the configuration has to 
be exactly right. Can you post what configuration you're using?

Based on the information provided, one guess is that you might have the 
IP statically configured on the interface (outside pacemaker), so that 
when you bring the interface up, the static configuration is taking 
effect. When a resource is managed by pacemaker, it should not be 
configured to start or stop by any other means.

Regarding the pull-the-cable test, what is your networking setup? Does 
each cluster node have a single network connection, or do you have a 
dedicated link for clustering traffic? Do you have any sort of STONITH 
configured?

-- Ken Gaillot <kjgaillo at gleim.com>
Network Operations Center, Gleim Publications