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From Benjamin Mahler <benjamin.mah...@gmail.com>
Subject Re: [Breaking bug fix] Binary in state endpoints
Date Tue, 03 Nov 2015 03:03:14 GMT
Sorry for the confusion, the motivation to remove 'data' is for memory
scalability reasons (the ability to express binary fields is orthogonal and
is not the reason to remove 'data').

We can get into a really bad state in large clusters if frameworks are
putting non-trivial amounts of 'data' in TaskInfos and ExecutorInfos. If
it's too large for the master to hold in memory, the master will
continually OOM and it becomes impossible to right your cluster. See
https://issues.apache.org/jira/browse/MESOS-1746 for some history of
stripping binary data, starting with TaskStatus.

Labels were introduced to aid tooling, can you use labels? I realize they
are not in ExecutorInfo yet.

On Mon, Nov 2, 2015 at 6:23 PM, David Greenberg <dsg123456789@gmail.com>
wrote:

> Why not base64 encode the field? We use that field in our frameworks, and
> some of our platform tools would benefit from being able to read that data.
> Base64 seems like a compromise with minimal complexity addition. It also
> removes the potential for parse errors, doesn't rule out future
> applications from using the data stored there (as specialized frameworks
> use that field), and doesn't incur a message size overhead in the (I
> presume) majority of frameworks not using that field.
> On Mon, Nov 2, 2015 at 4:28 PM Guangya Liu <gyliu513@gmail.com> wrote:
>
> > +1 to remove the field directly, one comment is that the upgrade document
> > may need to be updated.
> >
> > From my understanding, since the data is binary data and I did not see
> too
> > much requirement on retrieving binary data.
> >
> > Thanks!
> >
> > On Sat, Oct 24, 2015 at 5:33 AM, Joseph Wu <joseph@mesosphere.io> wrote:
> >
> > > Hello,
> > >
> > > The state endpoints, on master and agent, currently serialize two
> binary
> > > data fields in the ExecutorInfo and TaskInfo objects.  These fields are
> > set
> > > by frameworks; and Mesos does not inspect their values.
> > >
> > > The data fields can be found in the state JSON blobs:
> > > /master/state -> frameworks[*].executors[*].data
> > > /slave/state ->
> > >
> > >
> >
> frameworks[*].(executors|completed_executors)[*].(tasks|queued_tasks|completed_tasks)[*].data
> > >
> > > *Problem:*
> > > The state endpoints are JSON-ified in a non-standard way (i.e. not via
> > our
> > > normal Protobuf-to-json methods).  When we serialize the binary "data"
> > > fields, the binary is dumped as a string, as is.  The resulting JSON
> may
> > > not be valid if the binary data includes random bytes (i.e. not
> unicode).
> > > Most JSON parsers will error on the state endpoints in this case.
> > >
> > > *Proposed solution *(and breaking change)*:*
> > > Simple -- remove the "data" fields from the state endpoints.  (And only
> > > from the state endpoints.  The ExecutorInfo and TaskInfo objects will
> not
> > > change.)
> > >
> > > *Question:*
> > > We believe that frameworks/tools do not rely on retrieving the "data"
> > > fields from the state endpoints.
> > >
> > > Is there any framework/tool that retrieves the "data" field from the
> > state
> > > endpoints?
> > > And if so, is it critical to how the framework/tool works?
> > >
> > > More details here: https://issues.apache.org/jira/browse/MESOS-3771
> > >
> > > Thanks,
> > > ~Joseph
> > >
> >
>

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