[lvs-users] [Keepalived] Real IP and virtual IP not in the same subnet

Tom van Leeuwen tom.van.leeuwen at saasplaza.com
Fri Jul 8 06:14:35 BST 2011


Hi Stephane,

Probably stupid, but: have you also checked that VRRP packets are 
recieved correctly?
If you start 1 keepalived, does the other see the vrrp? Also: have you 
specified different (global def section) router_id's?
Also, can you verify that you can ping LVS node 2 from LVS node 1 and 
vice versa. Also verify that it really goes in/out of interface eth0.

With kind regards,
Tom van Leeuwen

On 07/08/2011 02:22 AM, Stephane RIOS wrote:
> Hi all
>
> This is slightly off-topic because it concerns especially keepalived and
> not lvs but i read a lot of posts in this list about keepalived so ...
> I've made a very simple setup of 2 LVS nodes (Debian 5.0) on Rackspace.
> And this setup does not work.
> Here's the MASTER keepalived conf :
>
> global_defs {
>       router_id my_router
> }
>
> vrrp_instance app_master {
>       state MASTER
>       interface eth0
>       virtual_router_id 36
>       priority 150
>       advert_int 1
>       nopreempt
>       garp_master_delay 5
>       virtual_ipaddress {
>           31.222.179.6
>       }
> }
>
> The BACKUP conf is quite the same except the "state" and "priority"
> directives of course.
>
> Simple, isn't it ?
>
> The real IPs of the 2 nodes are on the 31.222.176.xxx subnet and the
> virtual IP that Rackspace gave me is 31.222.179.6.
> It seems that everything is working fine except that VRRP packets are
> sent but not received by either one. So immediatly after the keepalived
> daemon start, the BACKUP node enters the MASTER state and i have two
> nodes in MASTER state (huh !).
>
> What i've done to check my config :
>
>    - tcpdump -qn net 224.0.0.0/8 : check that the VRRP packets are sent (OK)
>    - ip addr list : check that the two nodes got the virtual IP (OK but i
> don't want this !)
>    - netstat -g : check that the vrrp.mcast.net (224.0.0.18) multicat
> group is registered on the interface  (OK)
>    - iptables -F : delete all possible rules that could block
>
> I tried to replicate this config with 2 VMs on my own machine and
> everything worked fine. But I assigned real IPs and virtual IP in the
> same subnet.
> I also tried to add a /22 in the virtual_ipaddress field in the
> keepalived.conf but it didn't solve my problem.
>
> So my question is : does keepalived need to have Virtual IP and real IP
> in the same subnet to work ?
> Do I need to add a routing directive somewhere ?
>
> Thank you for your help
>




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