[lvs-users] netmask for vip?

Julian Anastasov ja at ssi.bg
Sat Jun 24 18:30:43 BST 2017


On Sat, 24 Jun 2017, linbo liao wrote:

> I search the net, all VIP will be removed if primary IP deleted when
> promote_secondaries is 0.

	Yes - if we add VIP/24 on eth0. Not - if VIP is added as /32.

> Why VIP should not be promoted as primary IP if DIP removed? I try to
> search in google, but no luck.

	Nobody should need such games in IPVS setups...
I just wanted to note all considerations when deciding
where to add VIP.

> > add DIP/24 on eth0 before configuring VIP. Such DIP is
> > mandatory for TUN mode because we originate IPIP packets
> > from DIP.

	If VIP becomes the primary source address when sending
to TUN real server, the real server can drop the IPIP packet
with saddr=VIP,daddr=RIP because VIP can be added as local
address on "lo". Also, there is no guarantee that such
packet can be routed to the RIP in all cases, sometimes
saddr=VIP can be allowed to use only the incoming ISP link.
So, as you see, it depends on many things.


Julian Anastasov <ja at ssi.bg>

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