Keepalived's virtual_router_id - should it be unique per node?

Question

I have two nodes running keepalived, and two VIP, e.g.

Node 1      Node 2
VIP1        VIP2

So in each node, I have two definition of vrrp_instance, so I assume the two vrrp_instance in my keepalived.conf suppose to be unique, but they can be the same values on another node, right?

Solution

Different VRRP instances should have different virtual_router_id values. Same VRRP instances should have the same value.

You can read the following from man keepalived.conf:

# arbitary unique number 0..255
# used to differentiate multiple instances of vrrpd
# running on the same NIC (and hence same socket).
virtual_router_id 51

To summarize, you need to have the same value on the members of same cluster. If you have another cluster, its members should have another value. The virtual_router_id should be unique per VRRP cluster.

Comments

[Ryan]

Hi, in my network I have any set of keepalived nodes which has the dupltcated virtual_router_id, but I have tested the function is ok, execept there are warning log syslog, does it matter? Also, is it recommended to use the same string for both vrrp_instance and virtual_router_id? Thanks