Hostnames in backend definition...

david raistrick drais at
Thu Dec 15 18:06:40 CET 2011

On Thu, 15 Dec 2011, Poul-Henning Kamp wrote:

>>> switch to the newly loaded VCL and you won't see your service as much
>>> as blink.
>> Don't forget to unload your old VCL, too (at least for 2.x), iirc.
> Why ?

So you stop sending probes to the old backend IP addresses.   Here are my 
notes from the discussion around it:

<Mithrandir> well, yes, you need to discard backends for probes to stop
<Mithrandir> this is intentional
<sky> vcl.discard old_config
<tonyflint> @keen discarding the boot vcl made my stale healthchecks stop
<tonyflint> fyi
<tonyflint> I didn't think of the boot one
<Mithrandir> just discarding right away should work.
<Mithrandir> I think there's a race condition if you discard it within a
              _really_ short time that you might hit
<phk> Mithrandir, huh ?
<Mithrandir> phk: at least in 2.1, I've seen asserts when people discard 
too quickly.
<phk> Mithrandir, I hope that one is solved in 2.1.4
<phk> possibly 2.1.3

david raistrick
drais at   

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