[Nottingham-pm] Monitoring website uptimes

Duncan Fyfe duncanfyfe at domenlas.com
Tue Jul 29 16:30:22 PDT 2014

On 29/07/14 20:33, Jim Driscoll wrote:
>> On 29 Jul 2014, at 19:45, Duncan Fyfe <duncanfyfe at domenlas.com> wrote:
>>> On 29/07/14 18:35, James Green wrote:
>>> Hey folks,
>>> Rather than my usual meeting-arranging blather on this list ... I have
>>> an actual Perl-related question! OK, it's not very Perl related.
>>> Following a bunch of recent conversations about the future of
>>> search.cpan.org, and the fact it was seemingly down all the time, I've
>>> started gathering stats on when both it, and metacpan.org, are
>>> unreachable.
>>> Unfortunately I'm getting a lot of what I suspect are false positives.
>>> I'm using LWP::UserAgent to get() a specific search page from each
>>> site, timing out after 30s, and if it hasn't loaded, considering it
>>> "down" until the next check. This process runs every 2 minutes, from
>>> cron. Quite often a site will fail to load just once, then be back up
>>> the next time -- which is as likely to be a transient routing problem
>>> at my end as an issue at theirs.
>>> Does anyone have experience monitoring the availability of websites,
>>> or exciting ideas for better approaches to this data?
>> Quick check, details below, but for starters it looks like there might
>> be a reverse DNS problem with metacpan.org. I'll have a more detailed
>> look later.
> Just a misconfiguration on one of the servers, unlikely to be anything to do with reverse DNS at all,

James' problem may not be due to a reverse DNS lookup problem but it
still stands that reverse DNS lookups on the metacpan.org IP addresses
fail (see the nslookup output in my first reply).

James - can you confirm it is the accessibility of search.cpan.org
itself that people are concerned about ie. can you check if it is CPAN
they have a problem with or a CPAN mirror  ?
I've had problems before with the CPAN mirrors "automagically" chosen by
cpan configuration before.

Back to your test script.  How frequent are the failures or put another
way, how many times would you expect to have to run it before you saw
a failure ?

Have fun,

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