Alex Rousskov wrote:
On 02/19/2010 09:12 PM, Amos Jeffries wrote:
This patch adds an advanced option to the Squid helper controls which
overrides Squid dying when helpers crash.
It has been found necessary in certain corner cases with PHP helpers
(which have system imposed limited lifetimes) where a proxy has
previously been under some load and helpers started then are timed out
later under low load as a bunch. Squid may die and restart.
If the proxy has been started under existing high load conditions (such
as a backup coming online) this case may also occur shortly after
startup. Leading to a chain reaction of restarts until load drops below
number of helpers needed to trigger a death.
These cases depend on external forces or helper design closing the
helpers outside Squid control.
There is one known issue with this option:
If the helpers are really dying due to some fatal issue during their
startup the use of this option would result in Squid hanging while
infinitely re-starting helpers and doing no request processing.
Missing squid.conf documentation update?
I think "immortal" is a little strange choice for helpers that die all
the time :-). How about "phoenix"? It is not an adjective but it fits:
phoenix
* A phoenix is an imaginary bird which, according to ancient stories,
burns itself to ashes every five hundred years and is then born again.
* If you describe someone or something as a phoenix, you mean that they
return again after seeming to disappear or be destroyed. N-SING literary
Cheers,
Alex.
The dynamic helpers are already phoenix. This is about making Squid
itself immortal to the flames as they regenerate.
I've left the doc out for now since I'm not sure I really want this to
be widely used until we can get rid of the fork bomb as Kinkie named it.
If anyone can think of a reliable way to detect broken helper crashes
while also permittig 100% of the helpers to exist at any given time
(real closure exit, not a crash). I'd really like to be able to do that
instead of all this close-per-time fudging.
Kinkie,
the non-use of this option keeps things flowing with detection of
N/30sec being fatal to Squid and aborting a fork loop. It's not working
too well when N=1 and count closing is >1 though.
Amos
--
Please be using
Current Stable Squid 2.7.STABLE8 or 3.0.STABLE24
Current Beta Squid 3.1.0.16
