[lvs-users] thoughts on making IPVS sync multicast address adjustable

Phillip Moore pdm at pobox.com
Tue Jun 30 21:59:12 BST 2015

Has any thought been giving to making the multicast address IPVS sync
daemons use to sync state be configurable? is in the link local multicast subnet. Our hope is to have
the IPVS directors be distributed in multiple L3 networks so the
multicast traffic would have to  be routed between them. This wouldn't
be a problem except for the choice of this link-local subnet is
treated specially by network vendors. Routing devices do not want to
route this and according to my network folks it would cause it to hit
the control plane and cause excessive usage on the routers where an
alternate multicast subnet would not.

Looking at the code it would appear some what trivial to change this
to a proc setting but I do not know the context or history of the
choice behind as the address to be hard coded.
Interestingly the IANA assignments document shows the .81 address as
being in a reserved range.

Our configuration idea is to have a small pool of directors all acting
as master and backup (running both daemons). We will anycast with
BGP/exabgp the VIP addresses to live on all of the directors which
would live on several subnets.

I appreciate any thoughts or feedback on this idea or experiences with
using the existing address at scale.

Phillip Moore

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