[development] No suitable nodes available at RackspaceCloud (Mosso)

[Cameron Eagans]

I dunno....I've run Drupal on some really slow servers, and the
modules page can take a LONG time to render. I guess it kind of
depends on the hardware they're using for Mosso, but I do agree with
the sentiment that it's probably not a timeout issue.

@Tomáš: If I were in your shoes and an issue like this was unresolved
after a year, I think I'd be strongly considering a new hosting
provider. Slicehost is fantastic. EC2 is a pretty good choice too (you
can just spin up the Mercury AMI and have a really sweet Drupal
hosting setup). I hear good things about Linode too.
-----
Cameron Eagans
Owner, Black Storms Studios, LLC
http://www.blackstormsstudios.com


On Thu, Feb 18, 2010 at 12:23 PM, larry at garfieldtech.com
<larry at garfieldtech.com> wrote:
>
> Drupal by design doesn't generate output of any kind until the last second, and then sends the entire page as one giant string.  That is what allows us to do all sorts of fun things in the theme layer or HTTP redirection before content gets sent.
>
> That said, if I understood the original message Rackspace is saying the proxy server is timing out after 30 *seconds* of no response?  Even the heaviest Drupal page shouldn't get anywhere near that time.  3-4 seconds for something other than selected admin pages is considered an eternity, at least for the PHP time.  There's something else going on here besides Drupal not being the fastest PHP app out there...
>
> --Larry Garfield
>
> Tomáš Fülöpp (vacilando.org) wrote:
>>
>> (Interesting, Brian; I also were promised shell pretty soon about a year ago. It's a shame - MediaTemple has shell /and /also a breakdown of compute cycles per script...)
>>
>> Anyway -- Victor's note about shortening PHP timeout brought me to thinking about measuring the time since the start of the execution and issuing flush() each time the process might time out.
>>
>> Two questions:
>>
>>   1. what is the most suitable Drupal function for this -- it needs to
>>      be something that runs regularly and for all kind of pages
>>   2. for Drupal, is it enough to issue flush() or is ob_end_flush()
>>      also needed, or something else
>>
>> Thanks a million for any ideas;
>>
>> Tomáš / Vacilando
>>
>>
>>
>> On Thu, Feb 18, 2010 at 15:46, Brian Vuyk <brian at brianvuyk.com <mailto:brian at brianvuyk.com>> wrote:
>>
>>    I've run into this with a few of my client sites, but they haven't
>>    even been high-traffic sites.
>>
>>    Personally, I just don't think the RS Cloud is a good match for
>>    Drupal. Combine that with the recent security issues they've had,
>>    occasional inexplicable downtime, the 'no suitable nodes' and the
>>    lack of a shell, and I am moving my sites away as quick as I can.
>>
>>    The shell issue is really sensitive for me - about 14 months ago, my
>>    previous host ran into... issues... and could no longer offer
>>    hosting. So, I was in a pinch and Rackspace (then Mosso) looked very
>>    good apart from the lack of a shell. I talked to their customer
>>    service reps, and was informed that shell access for the cloud was
>>    in pre-release testing, and was scheduled to go live the next week.
>>
>>    In a burst of poor judgement, I decided that the package they
>>    offered was good enough to do without shell access for a week, so I
>>    bought in, and transferred my sites. 14 months later, shell access
>>    still hasn't been released, and I've had to move all my more
>>    critical  / development-intensive sites off of their service in the
>>    meantime.
>>
>>    Brian
>>
>>
>>
>>
>>    Tomáš Fülöpp (vacilando.org <http://vacilando.org>) wrote:
>>>
>>>    Hi,
>>>
>>>    At RackspaceCloud (former Mosso) I've been plagued with a very
>>>    unfortunate problem that i crippling both my work and the work of
>>>    my clients -- namely the infamous error message "Unfortunately
>>>    there were no suitable nodes available to serve this request."
>>>    Those of you at RS Cloud must have bumped into it. It is cryptic
>>>    and happens unpredictably. The cloud is very stable and scalable,
>>>    but for any a little bit heavier Drupal installation people do
>>>    start getting these errors.
>>>
>>>    *Basically, it is a generic error thrown by load balanced systems
>>>    that occurs as a result of a script exceeding a maximum timeout
>>>    value (not the PHP timeout value!) If a client connection does not
>>>    receive a response from the server after approximately 30 to 60
>>>    seconds the load balancer will close the connection and the client
>>>    will immediately receive the error message. In most cases, the
>>>    script will continue to execute until it reaches completion,
>>>    throws an error, or times out on the server, but the client will
>>>    not see the page load as expected and will instead receive this
>>>    error.*
>>>
>>>    I've used Boost for anonymous pages, Parallel, Memcache, etc., all
>>>    of which helped and anonymous users /usually/ don't get this
>>>    error. The problem is with admin or any other a bit heavier work
>>>    of logged in users. Even for basic Drupal websites with not too
>>>    many modules! Pages like the list of modules, or the status page,
>>>    i.e. heavy database or file requests, or API calls in PHP, are
>>>    very likely to time out.
>>>
>>>    Over the past year I've had a number of discussions with techs and
>>>    admins at that cloud, but the situation is unresolved. They
>>>    recognize the problem but maintain this is due to the
>>>    special/unusual setup they use for their cloud. It is not a
>>>    problem for some other CMS / frameworks. E.g. a very heavy
>>>    MediaWiki installation runs just fine. Drupal seems to be less
>>>    compatible with their system, somehow, somewhere.
>>>
>>>    *Now, why do I mention all this in the development list? I've been
>>>    intrigued by one little ray of hope in their words: "if a client
>>>    connection does not receive a response from the server after
>>>    approximately 30 to 60 seconds the load balancer will close the
>>>    connection and the client will immediately receive the error
>>>    message". Their techs said if I were able to emit any kind of
>>>    intermediary response to the client /during /rendering of the
>>>    page, then this would be solved. *
>>>    Indeed, a bit like the Batch API works in Drupal (with that I
>>>    often run night-long scripts without problems). I wonder, maybe
>>>    this is a more generic problem for any system that employs load
>>>    balancers?
>>>
>>>    *So my questions to you, colleagues, is -- do you see any place in
>>>    Drupal processing chain that could be used, and approximately how,
>>>    to make sure that the load balancer keeps the connection opened.*
>>>    If you have any ideas, wild or proven, I will be happy to test and
>>>    develop them further and bring them back to the community, of
>>>    course. If this succeeds, I think many of us will be relieved (and
>>>    able to focus on development again!)
>>>
>>>    Thank you for any ideas - on and off this list.
>>>
>>>    Best regards,
>>>
>>>    Tomáš / Vacilando
>>>
>>
>>