Re: [PATCH v2 0/4] IPVS full NAT support + netfilter 'ipvs' matchsupport

From: Simon Horman
Date: Tue Sep 29 2009 - 19:18:58 EST


On Tue, Sep 29, 2009 at 05:07:24PM +0200, Hannes Eder wrote:
> On Tue, Sep 29, 2009 at 16:51, Simon Horman <horms@xxxxxxxxxxxx> wrote:
> > On Tue, Sep 29, 2009 at 02:35:15PM +0200, Hannes Eder wrote:
> >> The following series implements full NAT support for IPVS. ÂThe
> >> approach is via a minimal change to IPVS (make friends with
> >> nf_conntrack) and adding a netfilter matcher, kernel- and user-space
> >> part, i.e. xt_ipvs and libxt_ipvs.
> >
> > Its a bit late in the day for me to review the code, but I have a few
> > quick comments.
> >
> >>
> >> Example usage:
> >>
> >> % ipvsadm -A -t 192.168.100.30:80 -s rr
> >> % ipvsadm -a -t 192.168.100.30:80 -r 192.168.10.20:80 -m
> >> # ...
> >>
> >> # Source NAT for VIP 192.168.100.30:80
> >> % iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.100.30/32 \
> >> > --vport 80 -j SNAT --to-source 192.168.10.10
> >>
> >> or SNAT-ing only a specific real server:
> >>
> >> % iptables -t nat -A POSTROUTING --dst 192.168.11.20 \
> >> > -m ipvs --vaddr 192.168.100.30/32 -j SNAT --to-source 192.168.10.10
> >
> > If the iptables rule is not in place does LVS just use
> > its old NAT behaviour?
>
> Yes, without iptables rules LVS NAT does DNAT.

Great.

> >> First of all, thanks for all the feedback. ÂThis is the changelog for v2:
> >>
> >> - Make ip_vs_ftp work again. ÂSetup nf_conntrack expectations for
> >> Â related data connections (based on Julian's patch see
> >> Â http://www.ssi.bg/~ja/nfct/) and let nf_conntrack/nf_nat do the
> >> Â packet mangling and the TCP sequence adjusting.
> >>
> >> Â This change rises the question how to deal with ip_vs_sync? ÂDoes it
> >> Â work together with conntrackd? ÂWild idea: what about getting rid of
> >> Â ip_vs_sync and piggy packing all on nf_conntrack and use conntrackd?
> >>
> >> Â Any comments on this?
> >
> > Â ÂThat sounds like a reasonable suggestion.
> >
> > Â ÂI think that ip_vs_sync came along before conntrackd
> > Â Âand no one has given much thought to merging the functionality.
>
> Okay, I'll dig further in this direction.

Assuming the technical side is clean, I suspect the major problem will be
how to migrate users away from ip_vs_sync.
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