Mailing List Archive

Hello,

On Tue, 28 May 2013, Kash, Howard M CIV (US) wrote:

> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
> After upgrading kernels from 3.8.8 to 3.9.3, IPVS will no longer forward IPv6 DNS packets (UDP or TCP) to the real servers. IPv4 works with the 3.9.3 kernel. Booting back to the 3.8.8 kernel resolved the IPv6 issue. Any ideas?

Do you still see this problem? I'm not using
IPv6, may be others can help here.

Regards

--
Julian Anastasov <ja@ssi.bg>

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Classification: UNCLASSIFIED
Caveats: NONE


It appears to be an IPv6 routing issue rather than an IPVS issue. With the 3.8.8 kernel, the following routes to the real servers appear automatically in the routing table:

2001:x:x:x::30/128 2001:x:x:x::30 UC 0 694882451 2 bond0
2001:x:x:x::40/128 2001:x:x:x::40 UC 0 695098682 2 bond0
2001:x:x:x::50/128 2001:x:x:x::50 UC 0 870214 2 bond0

With the 3.9.3 kernel these route do not appear, and attempts to send DNS queries to the real server from the load balancer give "no route to host" errors. Manually adding routes fixes the issue:

route -A inet6 add 2001:x:x:x::30/128 gw 2001:x:x:x::30 dev bond0
route -A inet6 add 2001:x:x:x::40/128 gw 2001:x:x:x::40 dev bond0
route -A inet6 add 2001:x:x:x::50/128 gw 2001:x:x:x::50 dev bond0

This seems like a kludge, but I haven't figured out what the root cause of the issue is.


Howard


-----Original Message-----
From: Julian Anastasov [mailto:ja@ssi.bg]
Sent: Wednesday, June 19, 2013 5:10 AM
To: Kash, Howard M CIV (US)
Cc: lvs-users@linuxvirtualserver.org
Subject: Re: [lvs-users] IPv6 broken in 3.9 kernel? (UNCLASSIFIED)


Hello,

On Tue, 28 May 2013, Kash, Howard M CIV (US) wrote:

> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
> After upgrading kernels from 3.8.8 to 3.9.3, IPVS will no longer forward IPv6 DNS packets (UDP or TCP) to the real servers. IPv4 works with the 3.9.3 kernel. Booting back to the 3.8.8 kernel resolved the IPv6 issue. Any ideas?

Do you still see this problem? I'm not using
IPv6, may be others can help here.

Regards

--
Julian Anastasov <ja@ssi.bg>

Classification: UNCLASSIFIED
Caveats: NONE



_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users

Hello,

On Wed, 19 Jun 2013, Kash, Howard M CIV (US) wrote:

> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
> It appears to be an IPv6 routing issue rather than an IPVS issue. With the 3.8.8 kernel, the following routes to the real servers appear automatically in the routing table:
>
> 2001:x:x:x::30/128 2001:x:x:x::30 UC 0 694882451 2 bond0
> 2001:x:x:x::40/128 2001:x:x:x::40 UC 0 695098682 2 bond0
> 2001:x:x:x::50/128 2001:x:x:x::50 UC 0 870214 2 bond0
>
> With the 3.9.3 kernel these route do not appear, and attempts to send DNS queries to the real server from the load balancer give "no route to host" errors. Manually adding routes fixes the issue:
>
> route -A inet6 add 2001:x:x:x::30/128 gw 2001:x:x:x::30 dev bond0
> route -A inet6 add 2001:x:x:x::40/128 gw 2001:x:x:x::40 dev bond0
> route -A inet6 add 2001:x:x:x::50/128 gw 2001:x:x:x::50 dev bond0
>
> This seems like a kludge, but I haven't figured out what the root cause of the issue is.

Thanks for the explanation. I don't know IPv6 well
enough to comment...

Regards

--
Julian Anastasov <ja@ssi.bg>

_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users