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List: mesos-user
Subject: Re: statusUpdate() duplicate messages?
From: Vinod Kone <vinodkone () gmail ! com>
Date: 2015-11-18 18:05:02
Message-ID: CAAkWvAxm=eYbOPcmaP2Wfr-mq3KADS3XN+o03ninyNMB_g3rrQ () mail ! gmail ! com
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Look for UPDATE and ACKNOWLEDGE sections in
https://github.com/apache/mesos/blob/master/docs/scheduler-http-api.md for
semantics. Note that this doc for schedulers using the new HTTP API, but
the semantics around updates are the same.
On Wed, Nov 18, 2015 at 4:41 AM, James Vanns <jvanns.ilm@gmail.com> wrote:
> Thanks very much for the prompt response, Tom. I shall go and read up on
> reconciliation (I'd expected there to be something like this to read). And
> to my knowledge, no I don't explicitly disable the implicit status
> acknowledgement ;)
>
> Cheers,
>
> Jim
>
>
> On 18 November 2015 at 12:24, Tom Arnfeld <tom@duedil.com> wrote:
>
>> When you construct the scheduler, are you disabling implicit
>> acknowledgements?
>>
>> https://github.com/apache/mesos/blob/master/include/mesos/scheduler.hpp#L373
>>
>> I'd suggest having a read over this document, it explains some of this ->
>> http://mesos.apache.org/documentation/latest/reconciliation/
>>
>> a) Mesos may re-send messages if you don't acknowledge them, and task
>> status messages are guaranteed *at least once*
>> c) If you disable implicit status acknowledgement, yep
>> d) You should, they are guaranteed to be delivered *at some point* *at
>> least once* by the slave / master. To keep your framework in sync with
>> the cluster it is recommended to reconcile tasks often (as explained in the
>> document above)
>> e) http://mesos.apache.org/documentation/latest/reconciliation/
>>
>> Hope that helps, and I think that's all correct! The docs will be able to
>> clarify better :-)
>>
>> On 18 Nov 2015, at 12:09, James Vanns <jvanns.ilm@gmail.com> wrote:
>>
>> Hello list.
>>
>> We have an experimental framework (C++ API) based on Mesos 0.24 and we're
>> seeing duplicate task status messages -- eg. 2 'FINISHED' messages for a
>> single task. This may well be normal behaviour but I wasn't prepared for
>> it. Could someone point me in the direction of a decent description on
>> status updates/messages somewhere in the Mesos documentation? Or explain
>> the following;
>>
>> a) Is this normal (it's not just the FINISHED state)?
>> b) What might cause this behaviour (it's intermittent)?
>> c) I do not explicitly acknowledge receipt of these messages - should I!?
>> d) Should I treat these status update messages as reliable and robust!?
>> e) Where can I learn more about this kind of internal detail?
>>
>> Cheers,
>>
>> Jim
>>
>> --
>> Senior Code Pig
>> Industrial Light & Magic
>>
>>
>>
>
>
> --
> --
> Senior Code Pig
> Industrial Light & Magic
>
[Attachment #3 (text/html)]
<div dir="ltr">Look for UPDATE and ACKNOWLEDGE sections in <a \
href="https://github.com/apache/mesos/blob/master/docs/scheduler-http-api.md">https://github.com/apache/mesos/blob/master/docs/scheduler-http-api.md</a> \
for semantics. Note that this doc for schedulers using the new HTTP API, but the \
semantics around updates are the same.</div><div class="gmail_extra"><br><div \
class="gmail_quote">On Wed, Nov 18, 2015 at 4:41 AM, James Vanns <span \
dir="ltr"><<a href="mailto:jvanns.ilm@gmail.com" \
target="_blank">jvanns.ilm@gmail.com</a>></span> wrote:<br><blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex"><div dir="ltr">Thanks very much for the prompt response, Tom. \
I shall go and read up on reconciliation (I'd expected there to be something like \
this to read). And to my knowledge, no I don't explicitly disable the implicit \
status acknowledgement \
;)<div><br></div><div>Cheers,</div><div><br></div><div>Jim</div><div><br></div></div><div \
class="gmail_extra"><div><div class="h5"><br><div class="gmail_quote">On 18 November \
2015 at 12:24, Tom Arnfeld <span dir="ltr"><<a href="mailto:tom@duedil.com" \
target="_blank">tom@duedil.com</a>></span> wrote:<br><blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex"><div style="word-wrap:break-word">When you construct the \
scheduler, are you disabling implicit acknowledgements?<div><span \
style="white-space:pre-wrap"> </span><a \
href="https://github.com/apache/mesos/blob/master/include/mesos/scheduler.hpp#L373" \
target="_blank">https://github.com/apache/mesos/blob/master/include/mesos/scheduler.hpp#L373</a></div><div><br></div><div>I'd \
suggest having a read over this document, it explains some of this -> <a \
href="http://mesos.apache.org/documentation/latest/reconciliation/" \
target="_blank">http://mesos.apache.org/documentation/latest/reconciliation/</a></div><div><br></div><div>a) \
Mesos may re-send messages if you don't acknowledge them, and task status messages \
are guaranteed <b>at least once</b></div><div>c) If you disable implicit status \
acknowledgement, yep</div><div>d) You should, they are guaranteed to be delivered \
<b>at some point</b> <b>at least once</b> by the slave / master. To keep your \
framework in sync with the cluster it is recommended to reconcile tasks often (as \
explained in the document above)</div><div>e) <a \
href="http://mesos.apache.org/documentation/latest/reconciliation/" \
target="_blank">http://mesos.apache.org/documentation/latest/reconciliation/</a></div><div><br></div><div>Hope \
that helps, and I think that's all correct! The docs will be able to clarify better \
:-)</div><div><div><div><br></div><div><div><div><blockquote type="cite"><div>On 18 \
Nov 2015, at 12:09, James Vanns <<a href="mailto:jvanns.ilm@gmail.com" \
target="_blank">jvanns.ilm@gmail.com</a>> wrote:</div><br><div><div \
dir="ltr">Hello list.<div><br></div><div>We have an experimental framework (C++ API) \
based on Mesos 0.24 and we're seeing duplicate task status messages -- eg. 2 \
'FINISHED' messages for a single task. This may well be normal behaviour but \
I wasn't prepared for it. Could someone point me in the direction of a decent \
description on status updates/messages somewhere in the Mesos documentation? Or \
explain the following;</div><div><br></div><div>a) Is this normal (it's not just \
the FINISHED state)?<br></div><div>b) What might cause this behaviour (it's \
intermittent)?</div><div>c) I do not explicitly acknowledge receipt of these messages \
- should I!?</div><div>d) Should I treat these status update messages as reliable and \
robust!?</div><div>e) Where can I learn more about this kind of internal \
detail?</div><div><br></div><div>Cheers,</div><div><br></div><div>Jim</div><div><br></div><div><div><div><div \
dir="ltr"><div>--</div><div>Senior Code Pig</div><div>Industrial Light & \
Magic</div></div></div> </div></div></div>
</div></blockquote></div><br></div></div></div></div></div></blockquote></div><br><br \
clear="all"><div><br></div></div></div>-- <br><span class=""><div><div \
dir="ltr"><div>--</div><div>Senior Code Pig</div><div>Industrial Light & \
Magic</div></div></div> </span></div>
</blockquote></div><br></div>
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