Strange issue with probes

[Håvard Alsaker Futsæter]

Hi Dridi!

2018-01-12 10:42 GMT+01:00 Dridi Boukelmoune <dridi at varni.sh>:

> Hello Håvard, Luca,
>
> On Fri, Jan 12, 2018 at 10:13 AM, Håvard Alsaker Futsæter
> <havardf at met.no> wrote:
> > Hi! I have a problem with backend probes not beeing sent, that seems very
> > similar to what Luca Gervasi has reported(see below).
> > Luca: Did you ever figure out a fix?
>
> Guillaume brought this to my attention, but I haven't looked at it
> yet. What's surprising is that I don't recall changes in this area
> until _after_ the 5.2 release (so no changes for the whole 5.x
> series).
>
> > I run varnish version 5.1.3-1~xenial on ubuntu/xenial with kernel
> > 4.4.0-109-generic.
> >
> > The behaviour I see is that I start up varnish, varnish sends one backend
> > probe for each backend, bringing them up to Healthy status. After that,
> it
> > seems like there are no more backend probes sent.
> >
> > The backend replies correctly when I use curl, and anyway there is not
> > indication that a probe fails. They are simply not sent in the first
> place,
> > as far as I can tell.
> >
> > Here is an example of my backend configuration:
> >     .host = "foo1";
> >     .port = "8080";
> >     .connect_timeout = 0.4s;
> >     .first_byte_timeout = 12s;
> >     .between_bytes_timeout = 1s;
> >     .max_connections = 40;
> >     .probe = {
> >         .url        = "/healthcheck";
> >         .timeout    = 1s;
> >         .interval   = 6s;
> >         .window     = 5;
> >         .threshold  = 3;
> >      }
> > }
> >
> > My backend.list looks like this:
> > boot.foo1          probe      Healthy             4/5 Fri, 12 Jan 2018
> > 08:50:38 GMT
> > boot.foo2          probe      Healthy             4/5 Fri, 12 Jan 2018
> > 08:50:38 GMT
> >
> > and here is an extract from backend.list -p:
> > boot.foo1           probe      Healthy             4/5
> >   Current states  good:  4 threshold:  3 window:  5
> >   Average response time of good probes: 0.002105
> >   Oldest ================================================== Newest
> >   --------------------------------------------------------------44 Good
> IPv4
> >   --------------------------------------------------------------XX Good
> Xmit
> >   --------------------------------------------------------------RR Good
> Recv
> >   ------------------------------------------------------------HHHH Happy
> >
> >
> > And running "varnishlog -g raw -i Backend_health" gives me no results
> back.
> >
> > I also tested the exact same config on 5.2,1~xenial, but I get the same
> > problem there.
> >
> > I don't really understand what is going on here, or how I should proceed.
> > Any help would be greatly appreciated!
>
> The workaround is to override the probe's status with the
> `backend.set_health` command if you can't rely on probes (or in
> general if you wish to rely on external monitoring to change the
> status of a backend).
>
> If any of you two has a github account, please open an issue.
> Otherwise let me know and I will open one myself.
>
>
Thanks for the response! I have opened an issue about this now.

Best regards,
Håvard


> Dridi
>
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