From: yangxingwu <xingwu.yang@gmail.com>
To: Julian Anastasov <ja@ssi.bg>
Cc: Simon Horman <horms@verge.net.au>,
netdev@vger.kernel.org, lvs-devel@vger.kernel.org,
netfilter-devel@vger.kernel.org,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-doc@vger.kernel.org
Subject: Re: [PATCH] ipvs: Fix reuse connection if RS weight is 0
Date: Thu, 28 Oct 2021 10:50:00 +0800 [thread overview]
Message-ID: <CA+7U5JuxN1BSneYuiZde_kZRNpPDuT23Wn7_Uyv12yk26tXEzA@mail.gmail.com> (raw)
In-Reply-To: <35e6215-4fb3-5149-a888-67aa6fae958f@ssi.bg>
hello
On Thu, Oct 28, 2021 at 5:09 AM Julian Anastasov <ja@ssi.bg> wrote:
>
>
> Hello,
>
> On Wed, 27 Oct 2021, yangxingwu wrote:
>
> > what we want is if RS weight is 0, then no new connections should be
> > served even if conn_reuse_mode is 0, just as commit dc7b3eb900aa
> > ("ipvs: Fix reuse connection if real server is
> > dead") trying to do
> >
> > Pls let me know if there are any other issues of concern
>
> My concern is with the behaviour people expect
> from each sysctl var: conn_reuse_mode decides if port reuse
> is considered for rescheduling and expire_nodest_conn
> should have priority only for unavailable servers (nodest means
> No Destination), not in this case.
>
> We don't know how people use the conn_reuse_mode=0
> mode, one may bind to a local port and try to send multiple
> connections in a row with the hope they will go to same real
> server, i.e. as part from same "session", even while weight=0.
> If they do not want such behaviour (99% of the cases), they
> will use the default conn_reuse_mode=1. OTOH, you have different
> expectations for mode 0, not sure why but you do not want to use
> the default mode=1 which is safer to use. May be the setups
> forget to stay with conn_reuse_mode=1 on kernels 5.9+ and
> set the var to 0 ?
The problem is we can NOT decide what the customers do, many of them
run kubernetes with old versions of kube-proxy. And most importantly,
upgrade to new version is a very long and painful process, that's why
we want to fix this at the kernel level
> The problem with mentioned commit dc7b3eb900aa is that
> it breaks FTP and persistent connections while the goal of
> weight=0 is graceful inhibition of the server. We made
> the mistake to add priority for expire_nodest_conn when weight=0.
> This can be fixed with a !cp->control check. We do not want
> expire_nodest_conn to kill every connection during the
> graceful period.
ok, got it, I will try to fix this problem
> Regards
>
> --
> Julian Anastasov <ja@ssi.bg>
prev parent reply other threads:[~2021-10-28 2:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-25 11:59 [PATCH] ipvs: Fix reuse connection if RS weight is 0 yangxingwu
2021-10-25 18:12 ` Julian Anastasov
2021-10-26 2:54 ` yangxingwu
2021-10-26 5:44 ` Julian Anastasov
2021-10-26 6:13 ` yangxingwu
2021-10-27 1:43 ` yangxingwu
2021-10-27 21:09 ` Julian Anastasov
2021-10-28 2:50 ` yangxingwu [this message]
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