Re: Does fullconn do anything in backends where minconn/maxconn are not used on any server?
Got it, thank you for the confirmation!
On Wed, Nov 15, 2023, 10:30 PM Willy Tarreau wrote:
> Hello,
>
> On Wed, Nov 15, 2023 at 05:30:06PM -0600, JJ Graham wrote:
> > Hi there,
> >
> > Does fullconn do anything in backends where minconn/maxconn are not used
> on
> > any server? The documentation and previous answers to similar questions
> > seem to imply the answer is "no" but the fact that it gets set to a
> default
> > value ("10% of the sum of the maxconns of all frontends that may branch
> to
> > this backend") and the presence of the fullconn value in the "limit"
> column
> > on the stats page is causing some debate.
>
> I confirm that this value has no effect when there is no minconn setting.
> The
> fact that the value appears in this column (the same as the frontend's
> maxconn)
> is because since both are exclusive (a frontend only has a maxconn, a
> backend
> only has a fullconn), and they are closely related, it makes sense in
> terms of
> compactness of the stats output.
>
> Hoping this helps,
> Willy
>
Re: Does fullconn do anything in backends where minconn/maxconn are not used on any server?
Hello,
On Wed, Nov 15, 2023 at 05:30:06PM -0600, JJ Graham wrote:
> Hi there,
>
> Does fullconn do anything in backends where minconn/maxconn are not used on
> any server? The documentation and previous answers to similar questions
> seem to imply the answer is "no" but the fact that it gets set to a default
> value ("10% of the sum of the maxconns of all frontends that may branch to
> this backend") and the presence of the fullconn value in the "limit" column
> on the stats page is causing some debate.
I confirm that this value has no effect when there is no minconn setting. The
fact that the value appears in this column (the same as the frontend's maxconn)
is because since both are exclusive (a frontend only has a maxconn, a backend
only has a fullconn), and they are closely related, it makes sense in terms of
compactness of the stats output.
Hoping this helps,
Willy
Does fullconn do anything in backends where minconn/maxconn are not used on any server?
Hi there,
Does fullconn do anything in backends where minconn/maxconn are not used on
any server? The documentation and previous answers to similar questions
seem to imply the answer is "no" but the fact that it gets set to a default
value ("10% of the sum of the maxconns of all frontends that may branch to
this backend") and the presence of the fullconn value in the "limit" column
on the stats page is causing some debate.
Thanks!
JJ
Re: soft-stop stops runtime API, should that be optional?
On Tue, Nov 14, 2023 at 05:18:14PM -0800, Abhijeet Rastogi wrote:
> Hi,
>
> I'll appreciate a response on this, I was unable to get any guidance from
> docs.
>
> Thanks
>
> On Tue, Nov 7, 2023 at 3:37 PM Abhijeet Rastogi
> wrote:
>
> > Hi HAproxy community,
> >
> > In our HAproxy deployment, access to runtime API is extremely critical, it
> > is used for:-
> > - collecting metrics
> > - managing servers in a backend (SoT is not DNS, so we have to use runtime
> > API), etc
> >
> > I observed that, when soft-stop is in progress, we get the following error
> > while performing a connect.
> >
> > connect(5, {sa_family=AF_UNIX, sun_path="path/to/haproxy.sock"}, 60) = -1
> > ECONNREFUSED (Connection refused)
> > recvfrom(3, 0x7ffcc675fe10, 519, MSG_DONTWAIT, NULL, NULL) = -1 EAGAIN
> > (Resource temporarily unavailable)
> >
> > Due to this, we're unable to perform any operations or collect metrics
> > while haproxy is in soft stop, for us, that's a long time as we use the
> > current settings.
> >
> > close-spread-time 10m
> > hard-stop-after 11m
> >
> > "stats socket" (unix socket) is configured on one of the production
> > frontends, we're using version "version 2.8.0-01b97d-15 2023/09/26".
> >
> > Will it make sense if HAproxy had an option to not disable runtime API
> > during soft-stop, perhaps an argument
> > While exploring the code, I noticed that the soft-stop code stops all
> > "stoppable
> > listeners"
> > ,
> > I wonder if there's a way to make a listener non-stoppable?
> >
> > Are there any workarounds to getting around this limitation, while also
> > retaining the soft-stop behavior?
> > Our reason to use soft-stop is to do best-effort into gracefully draining
> > client connections (send Connection: close). We also don't have a way to
> > drain H2 connections proactively, but that's a discussion for another day.
> >
> > Cheers,
> > Abhijeet (https://abhi.host)
> >
>
Hi Abhijeet,
A soft stop would close the stats socket of the leaving process, so if
you are not attached anymore to the socket you can't do much. If you
keep a connection to the socket you won't have the problem, but you need
to configure the right timeout so the connection won't be closed.
A cleaner solution is to use the master CLI instead of the stats
socket, this is a socket which is attached to the master process, and
which is able to connect to leaving processes.
http://docs.haproxy.org/2.8/management.html#9.4
Regards,
--
William Lallemand
