Re: Ipv6 and preferred_lft

On 10/14/2013 05:11 PM, Ryan O'Hara wrote:> First, the setting is not
optional. It should be. This problem, which
> I am unable to recreate, only exists with you are using keepalived
> with both 'vrrp' and 'check' enabled. I understand this a common case,
> but not everybody uses keepalived's IPVS capabilities. I'm not sure
> that changing this behavior will not cause problems for other valid
> configurations.

Well, it is, imho.

If you're not using the VRRP-addresses for IPVS stuff, you'd probably
want to specify the netmask. Once you specified a netmask (other than
/128, obviously), the preferred_lft is left alone.

It's quite easy to reproduce the issues of not setting preferred_lft to
deprecated. Just ' ip addr add $ipv6address dev $interface' and see how
that address is used for all outgoing traffic. In both cases, whether
you use keepalived for vrrp only, or with IPVS, you (or at least I) do
not want the machine to use virtual addresses for it's own
communication. I want the machine to use it's own address for
communicating with the outside world.

AFAICS, this patch doesn't break anything if you're not using IPVS
stuff. But it does FIX a lot if you do.

> Also, the DaD optimization is better addressed using the sysctl
> settings:
> 
> net.ipv6.conf.*.optimistic_dad
> 
> Which can be set for all interfaces or per interface.

Why? If VRRP decides that the other end is gone, it probably is. Which
means that you are safe to assume that the address should be up and
running directly, instead of having to wait for DAD to give the ok.
Also, you may want to add some addresses of your own to the interface,
for which you do want to enable DAD. So disabling DAD just for these
addresses seems more finetuned than for the whole interface.

-- 
Kerio Connect in de Cloud? https://www.kerioindecloud.nl/
Mark Schouten | Tuxis Internet Engineering
KvK: 09218193 | http://www.tuxis.nl/
T: 0318 200208 | [email protected]

------------------------------------------------------------------------------
October Webinars: Code for Performance
Free Intel webinars can help you accelerate application performance.
Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from 
the latest Intel processors and coprocessors. See abstracts and register >
http://pubads.g.doubleclick.net/gampad/clk?id=60134071&iu=/4140/ostg.clktrk

_______________________________________________
Keepalived-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/keepalived-devel

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.15 (GNU/Linux)
Comment: Using GnuPG with Icedove - http://www.enigmail.net/

iEYEARECAAYFAlJcDQoACgkQBJsbGZrWF/92IwCgrmR6/EhtJ07ssZUIpdZWGZsi
o74AoLeKoQATzuHUVvjPMjbJadY36JyN
=PCzr
-----END PGP SIGNATURE-----