varnish health probe errors

[Giannis Zach]

Thank you Guillaume for the confirmation, I've done some tests by
increasing the timeout and the failed health probes were decreased,
unfortunately, I've had to increase the timeout to 15 seconds which makes
me think that something is wrong with the network.

--
Giannis

On Thu, 29 Aug 2019 at 17:17, Guillaume Quintard <
guillaume at varnish-software.com> wrote:

> Hi,
>
> I think you got everything right: on the Varnish side, the connection was
> established (4) and successfully transmitted (X), we just never received a
> response, so yes, this has to do with timing out, most probably.
>
> --
> Guillaume Quintard
>
>
> On Thu, Aug 29, 2019 at 12:34 AM Giannis Zach <i.zachari at gmail.com> wrote:
>
>> Hello all,
>>
>> a successful health probe will log this flags `4--X-RH` and from the
>> documentation the flags are:
>> 4 -- IPv4 connection established
>> X -- Request transmit succeeded
>> R -- Read response succeeded
>> H -- Happy with the result
>>
>> The issue I'm facing is that sometimes the health probe returns the flags
>> `4--X---` marking the backend as sick.
>>
>> Can someone please explain to me when a varnish health probe will not log
>> an `R` (Read response succeeded)? Is this related to the health probe's
>> timeout value? Does this mean that the TCP connection failed before the
>> backend sent the response? The backend doesn't even log the request in its
>> access log, so from my understanding, the backend never received that
>> request, however, varnish says the request was successfully transmitted
>> (the `X` flag).
>>
>> Thank you for your time.
>>
>> --
>> Giannis
>> _______________________________________________
>> varnish-misc mailing list
>> varnish-misc at varnish-cache.org
>> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>>
>

-- 
Giannis Zachariadis
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