Hi,
As said above - I list again all comments from this thread so we
can see what's left and finalize all pending issues.
Comments from Jay:
1. This is much needed functionality, but there are a lot of the so let's
really think these protocols through. We really want to end up with a set
of well thought-out, orthoganol apis. For this reason I think it is really
important to think through the end state even if that includes APIs we
won't implement in the first phase.
A: Definitely behind this. Would appreciate if there are concrete comments
how this can be improved.
2. Let's please please please wait until we have switched the server over
to the new java protocol definitions. If we add upteen more ad hoc scala
objects that is just generating more work for the conversion we know we
have to do.
A: Fixed in the latest patch - removed scala protocol classes.
3. This proposal introduces a new type of optional parameter. This is
inconsistent with everything else in the protocol where we use -1 or some
other marker value. You could argue either way but let's stick with that
for consistency. For clients that implemented the protocol in a better way
than our scala code these basic primitives are hard to change.
A: Fixed in the latest patch - removed MaybeOf type and changed protocol
accordingly.
4. ClusterMetadata: This seems to duplicate TopicMetadataRequest which has
brokers, topics, and partitions. I think we should rename that request
ClusterMetadataRequest (or just MetadataRequest) and include the id of the
controller. Or are there other things we could add here?
A: I agree. Updated the KIP. Let's extends TopicMetadata to version 2 and
include controller.
5. We have a tendency to try to make a lot of requests that can only go to
particular nodes. This adds a lot of burden for client implementations (it
sounds easy but each discovery can fail in many parts so it ends up being a
full state machine to do right). I think we should consider making admin
commands and ideally as many of the other apis as possible available on all
brokers and just redirect to the controller on the broker side. Perhaps
there would be a general way to encapsulate this re-routing behavior.
A: It's a very interesting idea, but seems there are some concerns about
this
feature (like performance considerations, how this will complicate server
etc).
I believe this shouldn't be a blocker. If this feature is implemented at
some
point it won't affect Admin changes - at least no changes to public API
will be required.
6. We should probably normalize the key value pairs used for configs rather
than embedding a new formatting. So two strings rather than one with an
internal equals sign.
A: Fixed in the latest patch - normalized configs and changed protocol
accordingly.
7. Is the postcondition of these APIs that the command has begun or that
the command has been completed? It is a lot more usable if the command has
been completed so you know that if you create a topic and then publish to
it you won't get an exception about there being no such topic.
A: For long running requests (like reassign partitions) - the post
condition is
command has begun - so we don't block the client. In case of your example -
topic commands, this will be refactored and topic commands will be executed
immediately, since the Controller will serve Admin requests
(follow-up ticket KAFKA-1777).
8. Describe topic and list topics duplicate a lot of stuff in the metadata
request. Is there a reason to give back topics marked for deletion? I feel
like if we just make the post-condition of the delete command be that the
topic is deleted that will get rid of the need for this right? And it will
be much more intuitive.
A: Fixed in the latest patch - removed topics marked for deletion in
ListTopicsRequest.
9. Should we consider batching these requests? We have generally tried to
allow multiple operations to be batched. My suspicion is that without this
we will get a lot of code that does something like
for(topic: adminClient.listTopics())
adminClient.describeTopic(topic)
this code will work great when you test on 5 topics but not do as well if
you have 50k.
A: Updated the KIP - please check "Topic Admin Schema" section.
10. I think we should also discuss how we want to expose a programmatic JVM
client api for these operations. Currently people rely on AdminUtils which
is totally sketchy. I think we probably need another client under clients/
that exposes administrative functionality. We will need this just to
properly test the new apis, I suspect. We should figure out that API.
A: Updated the KIP - please check "Admin Client" section with an initial
API proposal.
11. The other information that would be really useful to get would be
information about partitions--how much data is in the partition, what are
the segment offsets, what is the log-end offset (i.e. last offset), what is
the compaction point, etc. I think that done right this would be the
successor to the very awkward OffsetRequest we have today.
A: I removed ConsumerGroupOffsetsRequest in the latest patch. I believe
this should
be resolved in a separate KIP / jira ticket.
12. Generally we can do good error handling without needing custom
server-side
messages. I.e. generally the client has the context to know that if it got
an error that the topic doesn't exist to say "Topic X doesn't exist" rather
than "error code 14" (or whatever). Maybe there are specific cases where
this is hard? If we want to add server-side error messages we really do
need to do this in a consistent way across the protocol.
A: Updated the KIP - please check "Protocol Errors" section. I added the
comprehensive, fine-grained list of error codes.
Comments from Guozhang:
13. Describe topic request: it would be great to go beyond just batching on
topic name regex for this request. For example, a very common use case of
the topic command is to list all topics whose config A's value is B. With
topic name regex then we have to first retrieve __all__ topics's
description info and then filter at the client end, which will be a huge
burden on ZK.
AND
14. Config K-Vs in create topic: this is related to the previous point;
maybe we can add another metadata K-V or just a metadata string along side
with config K-V in create topic like we did for offset commit request. This
field can be quite useful in storing information like "owner" of the topic
who issue the create command, etc, which is quite important for a
multi-tenant setting. Then in the describe topic request we can also batch
on regex of the metadata field.
A: As discussed it is very interesting but can be implemented later after
we have some basic functionality there.
15. Today all the admin operations are async in the sense that command will
return once it is written in ZK, and that is why we need extra verification
like testUtil.waitForTopicCreated() / verify partition reassignment
request, etc. With admin requests we could add a flag to enable / disable
synchronous requests; when it is turned on, the response will not return
until the request has been completed. And for async requests we can add a
"token" field in the response, and then only need a general "admin
verification request" with the given token to check if the async request
has been completed.
A: I see your point. My idea was to provide specific Verify...Request per
each
long running request, where needed. We can do it the way you suggest. The
only
concern is that introducing a token we again will make schema "dynamic". We
wanted
to do similar thing introducing single AdminRequest for all topic commands
but rejected
this idea because we wanted to have schema defined. So this is more a
choice between:
a) have fixed schema but introduce each time new Verify...Request for
long-running requests
b) use one request for verification but generalize it with token
I'm fine with whatever decision community come to. Just let me know your
thoughts.
Comment from Gwen:
16. Specifically for ownership, I think the plan is to add ACL (it sounds
like you are describing ACL) via an external system (Argus, Sentry).
I remember KIP-11 described this, but I can't find the KIP any longer.
A: Okay, no problem. Not sure though how we are going to handle it. Wait
which KIP
will be committed first and include changes to TopicMetadata from the later
one?
Anyway, I added this note to "Open Questions" section so we don't miss this
piece.
Thanks,
Andrii Biletskyi
On Fri, Mar 13, 2015 at 12:34 AM, Andrii Biletskyi <
andrii.bilets...@stealth.ly> wrote:
> Hi all,
>
> Today I uploaded the patch that covers some of the discussed and agreed
> items:
> - removed MaybeOf optional type
> - switched to java protocol definitions
> - simplified messages (normalized configs, removed topic marked for
> deletion)
>
> I also updated the KIP-4 with respective changes and wrote down my
> proposal for
> pending items:
> - Batch Admin Operations -> updated Wire Protocol schema proposal
> - Remove ClusterMetadata -> changed to extend TopicMetadataRequest
> - Admin Client -> updated my initial proposal to reflect batching
> - Error codes -> proposed fine-grained error code instead of
> AdminRequestFailed
>
> I will also send a separate email to cover all comments from this thread.
>
> Thanks,
> Andrii Biletskyi
>
>
> On Thu, Mar 12, 2015 at 9:26 PM, Gwen Shapira <gshap...@cloudera.com>
> wrote:
>
>> Found KIP-11 (
>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-11+-+Authorization+Interface
>> )
>> It actually specifies changes to the Metadata protocol, so making sure
>> both KIPs are consistent in this regard will be good.
>>
>> On Thu, Mar 12, 2015 at 12:21 PM, Gwen Shapira <gshap...@cloudera.com>
>> wrote:
>> > Specifically for ownership, I think the plan is to add ACL (it sounds
>> > like you are describing ACL) via an external system (Argus, Sentry).
>> > I remember KIP-11 described this, but I can't find the KIP any longer.
>> >
>> > Regardless, I think KIP-4 focuses on getting information that already
>> > exists from Kafka brokers, not on adding information that perhaps
>> > should exist but doesn't yet?
>> >
>> > Gwen
>> >
>> >
>> >
>> >
>> >
>> > On Thu, Mar 12, 2015 at 6:37 AM, Guozhang Wang <wangg...@gmail.com>
>> wrote:
>> >> Folks,
>> >>
>> >> Just want to elaborate a bit more on the create-topic metadata and
>> batching
>> >> describe-topic based on config / metadata in my previous email as we
>> work
>> >> on KAFKA-1694. The main motivation is to have some sort of topic
>> management
>> >> mechanisms, which I think is quite important in a multi-tenant / cloud
>> >> architecture: today anyone can create topics in a shared Kafka
>> cluster, but
>> >> there is no concept or "ownership" of topics that are created by
>> different
>> >> users. For example, at LinkedIn we basically distinguish topic owners
>> via
>> >> some casual topic name prefix, which is a bit awkward and does not fly
>> as
>> >> we scale our customers. It would be great to use describe-topics such
>> as:
>> >>
>> >> Describe all topics that is created by me.
>> >>
>> >> Describe all topics whose retention time is overriden to X.
>> >>
>> >> Describe all topics whose writable group include user Y (this is
>> related to
>> >> authorization), etc..
>> >>
>> >> One possible way to achieve this is to add a metadata file in the
>> >> create-topic request, whose value will also be written ZK as we create
>> the
>> >> topic; then describe-topics can choose to batch topics based on 1) name
>> >> regex, 2) config K-V matching, 3) metadata regex, etc.
>> >>
>> >> Thoughts?
>> >>
>> >> Guozhang
>> >>
>> >> On Thu, Mar 5, 2015 at 4:37 PM, Guozhang Wang <wangg...@gmail.com>
>> wrote:
>> >>
>> >>> Thanks for the updated wiki. A few comments below:
>> >>>
>> >>> 1. Error description in response: I think if some errorCode could
>> indicate
>> >>> several different error cases then we should really change it to
>> multiple
>> >>> codes. In general the errorCode itself would be precise and
>> sufficient for
>> >>> describing the server side errors.
>> >>>
>> >>> 2. Describe topic request: it would be great to go beyond just
>> batching on
>> >>> topic name regex for this request. For example, a very common use
>> case of
>> >>> the topic command is to list all topics whose config A's value is B.
>> With
>> >>> topic name regex then we have to first retrieve __all__ topics's
>> >>> description info and then filter at the client end, which will be a
>> huge
>> >>> burden on ZK.
>> >>>
>> >>> 3. Config K-Vs in create topic: this is related to the previous point;
>> >>> maybe we can add another metadata K-V or just a metadata string along
>> side
>> >>> with config K-V in create topic like we did for offset commit
>> request. This
>> >>> field can be quite useful in storing information like "owner" of the
>> topic
>> >>> who issue the create command, etc, which is quite important for a
>> >>> multi-tenant setting. Then in the describe topic request we can also
>> batch
>> >>> on regex of the metadata field.
>> >>>
>> >>> 4. Today all the admin operations are async in the sense that command
>> will
>> >>> return once it is written in ZK, and that is why we need extra
>> verification
>> >>> like testUtil.waitForTopicCreated() / verify partition reassignment
>> >>> request, etc. With admin requests we could add a flag to enable /
>> disable
>> >>> synchronous requests; when it is turned on, the response will not
>> return
>> >>> until the request has been completed. And for async requests we can
>> add a
>> >>> "token" field in the response, and then only need a general "admin
>> >>> verification request" with the given token to check if the async
>> request
>> >>> has been completed.
>> >>>
>> >>> 5. +1 for extending Metadata request to include controller /
>> coordinator
>> >>> information, and then we can remove the ConsumerMetadata /
>> ClusterMetadata
>> >>> requests.
>> >>>
>> >>> Guozhang
>> >>>
>> >>> On Tue, Mar 3, 2015 at 10:23 AM, Joel Koshy <jjkosh...@gmail.com>
>> wrote:
>> >>>
>> >>>> Thanks for sending that out Joe - I don't think I will be able to
>> make
>> >>>> it today, so if notes can be sent out afterward that would be great.
>> >>>>
>> >>>> On Mon, Mar 02, 2015 at 09:16:13AM -0800, Gwen Shapira wrote:
>> >>>> > Thanks for sending this out Joe. Looking forward to chatting with
>> >>>> everyone :)
>> >>>> >
>> >>>> > On Mon, Mar 2, 2015 at 6:46 AM, Joe Stein <joe.st...@stealth.ly>
>> wrote:
>> >>>> > > Hey, I just sent out a google hangout invite to all pmc,
>> committers
>> >>>> and
>> >>>> > > everyone I found working on a KIP. If I missed anyone in the
>> invite
>> >>>> please
>> >>>> > > let me know and can update it, np.
>> >>>> > >
>> >>>> > > We should do this every Tuesday @ 2pm Eastern Time. Maybe we can
>> get
>> >>>> INFRA
>> >>>> > > help to make a google account so we can manage better?
>> >>>> > >
>> >>>> > > To discuss
>> >>>> > >
>> >>>>
>> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
>> >>>> > > in progress and related JIRA that are interdependent and common
>> work.
>> >>>> > >
>> >>>> > > ~ Joe Stein
>> >>>> > >
>> >>>> > > On Tue, Feb 24, 2015 at 2:59 PM, Jay Kreps <jay.kr...@gmail.com>
>> >>>> wrote:
>> >>>> > >
>> >>>> > >> Let's stay on Google hangouts that will also record and make the
>> >>>> sessions
>> >>>> > >> available on youtube.
>> >>>> > >>
>> >>>> > >> -Jay
>> >>>> > >>
>> >>>> > >> On Tue, Feb 24, 2015 at 11:49 AM, Jeff Holoman <
>> >>>> jholo...@cloudera.com>
>> >>>> > >> wrote:
>> >>>> > >>
>> >>>> > >> > Jay / Joe
>> >>>> > >> >
>> >>>> > >> > We're happy to send out a Webex for this purpose. We could
>> record
>> >>>> the
>> >>>> > >> > sessions if there is interest and publish them out.
>> >>>> > >> >
>> >>>> > >> > Thanks
>> >>>> > >> >
>> >>>> > >> > Jeff
>> >>>> > >> >
>> >>>> > >> > On Tue, Feb 24, 2015 at 11:28 AM, Jay Kreps <
>> jay.kr...@gmail.com>
>> >>>> wrote:
>> >>>> > >> >
>> >>>> > >> > > Let's try to get the technical hang-ups sorted out, though.
>> I
>> >>>> really
>> >>>> > >> > think
>> >>>> > >> > > there is some benefit to live discussion vs writing. I am
>> >>>> hopeful that
>> >>>> > >> if
>> >>>> > >> > > we post instructions and give ourselves a few attempts we
>> can
>> >>>> get it
>> >>>> > >> > > working.
>> >>>> > >> > >
>> >>>> > >> > > Tuesday at that time would work for me...any objections?
>> >>>> > >> > >
>> >>>> > >> > > -Jay
>> >>>> > >> > >
>> >>>> > >> > > On Tue, Feb 24, 2015 at 8:18 AM, Joe Stein <
>> joe.st...@stealth.ly
>> >>>> >
>> >>>> > >> wrote:
>> >>>> > >> > >
>> >>>> > >> > > > Weekly would be great maybe like every Tuesday ~ 1pm ET /
>> 10am
>> >>>> PT
>> >>>> > >> ????
>> >>>> > >> > > >
>> >>>> > >> > > > I don't mind google hangout but there is always some
>> issue or
>> >>>> > >> whatever
>> >>>> > >> > so
>> >>>> > >> > > > we know the apache irc channel works. We can start there
>> and
>> >>>> see how
>> >>>> > >> it
>> >>>> > >> > > > goes? We can pull transcripts too and associate to
>> tickets if
>> >>>> need be
>> >>>> > >> > > makes
>> >>>> > >> > > > it helpful for things.
>> >>>> > >> > > >
>> >>>> > >> > > > ~ Joestein
>> >>>> > >> > > >
>> >>>> > >> > > > On Tue, Feb 24, 2015 at 11:10 AM, Jay Kreps <
>> >>>> jay.kr...@gmail.com>
>> >>>> > >> > wrote:
>> >>>> > >> > > >
>> >>>> > >> > > > > We'd talked about doing a Google Hangout to chat about
>> this.
>> >>>> What
>> >>>> > >> > about
>> >>>> > >> > > > > generalizing that a little further...I actually think it
>> >>>> would be
>> >>>> > >> > good
>> >>>> > >> > > > for
>> >>>> > >> > > > > everyone spending a reasonable chunk of their week on
>> Kafka
>> >>>> stuff
>> >>>> > >> to
>> >>>> > >> > > > maybe
>> >>>> > >> > > > > sync up once a week. I think we could use time to talk
>> >>>> through
>> >>>> > >> design
>> >>>> > >> > > > > stuff, make sure we are on top of code reviews, talk
>> through
>> >>>> any
>> >>>> > >> > tricky
>> >>>> > >> > > > > issues, etc.
>> >>>> > >> > > > >
>> >>>> > >> > > > > We can make it publicly available so that any one can
>> follow
>> >>>> along
>> >>>> > >> > who
>> >>>> > >> > > > > likes.
>> >>>> > >> > > > >
>> >>>> > >> > > > > Any interest in doing this? If so I'll try to set it up
>> >>>> starting
>> >>>> > >> next
>> >>>> > >> > > > week.
>> >>>> > >> > > > >
>> >>>> > >> > > > > -Jay
>> >>>> > >> > > > >
>> >>>> > >> > > > > On Tue, Feb 24, 2015 at 3:57 AM, Andrii Biletskyi <
>> >>>> > >> > > > > andrii.bilets...@stealth.ly> wrote:
>> >>>> > >> > > > >
>> >>>> > >> > > > > > Hi all,
>> >>>> > >> > > > > >
>> >>>> > >> > > > > > I've updated KIP page, fixed / aligned document
>> structure.
>> >>>> Also I
>> >>>> > >> > > added
>> >>>> > >> > > > > > some
>> >>>> > >> > > > > > very initial proposal for AdminClient so we have
>> something
>> >>>> to
>> >>>> > >> start
>> >>>> > >> > > > from
>> >>>> > >> > > > > > while
>> >>>> > >> > > > > > discussing the KIP.
>> >>>> > >> > > > > >
>> >>>> > >> > > > > >
>> >>>> > >> > > > > >
>> >>>> > >> > > > >
>> >>>> > >> > > >
>> >>>> > >> > >
>> >>>> > >> >
>> >>>> > >>
>> >>>>
>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations
>> >>>> > >> > > > > >
>> >>>> > >> > > > > > Thanks,
>> >>>> > >> > > > > > Andrii Biletskyi
>> >>>> > >> > > > > >
>> >>>> > >> > > > > > On Wed, Feb 18, 2015 at 9:01 PM, Andrii Biletskyi <
>> >>>> > >> > > > > > andrii.bilets...@stealth.ly> wrote:
>> >>>> > >> > > > > >
>> >>>> > >> > > > > > > Jay,
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > > > Re error messages: you are right, in most cases
>> client
>> >>>> will
>> >>>> > >> have
>> >>>> > >> > > > enough
>> >>>> > >> > > > > > > context to show descriptive error message. My
>> concern is
>> >>>> that
>> >>>> > >> we
>> >>>> > >> > > will
>> >>>> > >> > > > > > have
>> >>>> > >> > > > > > > to
>> >>>> > >> > > > > > > add lots of new error codes for each possible
>> error. Of
>> >>>> course,
>> >>>> > >> > we
>> >>>> > >> > > > > could
>> >>>> > >> > > > > > > reuse
>> >>>> > >> > > > > > > some of existing like UknownTopicOrPartitionCode,
>> but we
>> >>>> will
>> >>>> > >> > also
>> >>>> > >> > > > need
>> >>>> > >> > > > > > to
>> >>>> > >> > > > > > > add smth like: TopicAlreadyExistsCode,
>> >>>> TopicConfigInvalid (both
>> >>>> > >> > for
>> >>>> > >> > > > > topic
>> >>>> > >> > > > > > > name and config, and probably user would like to
>> know
>> >>>> what
>> >>>> > >> > exactly
>> >>>> > >> > > > > > > is wrong in his config), InvalidReplicaAssignment,
>> >>>> > >> InternalError
>> >>>> > >> > > > (e.g.
>> >>>> > >> > > > > > > zookeeper failure) etc.
>> >>>> > >> > > > > > > And this is only for TopicCommand, we will also
>> need to
>> >>>> add
>> >>>> > >> > similar
>> >>>> > >> > > > > stuff
>> >>>> > >> > > > > > > for
>> >>>> > >> > > > > > > ReassignPartitions, PreferredReplica. So we'll end
>> up
>> >>>> with a
>> >>>> > >> > large
>> >>>> > >> > > > list
>> >>>> > >> > > > > > of
>> >>>> > >> > > > > > > error codes, used only in Admin protocol.
>> >>>> > >> > > > > > > Having said that, I agree my proposal is not
>> consistent
>> >>>> with
>> >>>> > >> > other
>> >>>> > >> > > > > cases.
>> >>>> > >> > > > > > > Maybe we can find better solution or something
>> >>>> in-between.
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > > > Re Hangout chat: I think it is a great idea. This
>> way we
>> >>>> can
>> >>>> > >> move
>> >>>> > >> > > on
>> >>>> > >> > > > > > > faster.
>> >>>> > >> > > > > > > Let's agree somehow on date/time so people can join.
>> >>>> Will work
>> >>>> > >> > for
>> >>>> > >> > > me
>> >>>> > >> > > > > > this
>> >>>> > >> > > > > > > and
>> >>>> > >> > > > > > > next week almost anytime if agreed in advance.
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > > > Thanks,
>> >>>> > >> > > > > > > Andrii
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > > > On Wed, Feb 18, 2015 at 7:09 PM, Jay Kreps <
>> >>>> > >> jay.kr...@gmail.com>
>> >>>> > >> > > > > wrote:
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > > >> Hey Andrii,
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > > >> Generally we can do good error handling without
>> needing
>> >>>> custom
>> >>>> > >> > > > > > server-side
>> >>>> > >> > > > > > >> messages. I.e. generally the client has the
>> context to
>> >>>> know
>> >>>> > >> that
>> >>>> > >> > > if
>> >>>> > >> > > > it
>> >>>> > >> > > > > > got
>> >>>> > >> > > > > > >> an error that the topic doesn't exist to say
>> "Topic X
>> >>>> doesn't
>> >>>> > >> > > exist"
>> >>>> > >> > > > > > >> rather
>> >>>> > >> > > > > > >> than "error code 14" (or whatever). Maybe there are
>> >>>> specific
>> >>>> > >> > cases
>> >>>> > >> > > > > where
>> >>>> > >> > > > > > >> this is hard? If we want to add server-side error
>> >>>> messages we
>> >>>> > >> > > really
>> >>>> > >> > > > > do
>> >>>> > >> > > > > > >> need to do this in a consistent way across the
>> protocol.
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > > >> I still have a bunch of open questions here from my
>> >>>> previous
>> >>>> > >> > > list. I
>> >>>> > >> > > > > > will
>> >>>> > >> > > > > > >> be out for the next few days for Strata though.
>> Maybe
>> >>>> we could
>> >>>> > >> > do
>> >>>> > >> > > a
>> >>>> > >> > > > > > Google
>> >>>> > >> > > > > > >> Hangout chat on any open issues some time towards
>> the
>> >>>> end of
>> >>>> > >> > next
>> >>>> > >> > > > week
>> >>>> > >> > > > > > for
>> >>>> > >> > > > > > >> anyone interested in this ticket? I have a feeling
>> that
>> >>>> might
>> >>>> > >> > > > progress
>> >>>> > >> > > > > > >> things a little faster than email--I think we
>> could talk
>> >>>> > >> through
>> >>>> > >> > > > those
>> >>>> > >> > > > > > >> issues I brought up fairly quickly...
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > > >> -Jay
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > > >> On Wed, Feb 18, 2015 at 7:27 AM, Andrii Biletskyi <
>> >>>> > >> > > > > > >> andrii.bilets...@stealth.ly> wrote:
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > > >> > Hi all,
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > I'm trying to address some of the issues which
>> were
>> >>>> > >> mentioned
>> >>>> > >> > > > > earlier
>> >>>> > >> > > > > > >> about
>> >>>> > >> > > > > > >> > Admin RQ/RP format. One of those was about
>> batching
>> >>>> > >> > operations.
>> >>>> > >> > > > What
>> >>>> > >> > > > > > if
>> >>>> > >> > > > > > >> we
>> >>>> > >> > > > > > >> > follow TopicCommand approach and let people
>> specify
>> >>>> > >> topic-name
>> >>>> > >> > > by
>> >>>> > >> > > > > > >> regexp -
>> >>>> > >> > > > > > >> > would that cover most of the use cases?
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > Secondly, is what information should we generally
>> >>>> provide in
>> >>>> > >> > > Admin
>> >>>> > >> > > > > > >> > responses.
>> >>>> > >> > > > > > >> > I realize that Admin commands don't imply they
>> will
>> >>>> be used
>> >>>> > >> > only
>> >>>> > >> > > > in
>> >>>> > >> > > > > > CLI
>> >>>> > >> > > > > > >> > but,
>> >>>> > >> > > > > > >> > it seems to me, CLI is a very important client
>> of this
>> >>>> > >> > feature.
>> >>>> > >> > > In
>> >>>> > >> > > > > > this
>> >>>> > >> > > > > > >> > case,
>> >>>> > >> > > > > > >> > seems logical, we would like to provide users
>> with
>> >>>> rich
>> >>>> > >> > > experience
>> >>>> > >> > > > > in
>> >>>> > >> > > > > > >> terms
>> >>>> > >> > > > > > >> > of
>> >>>> > >> > > > > > >> > getting results / errors of the executed
>> commands.
>> >>>> Usually
>> >>>> > >> we
>> >>>> > >> > > > supply
>> >>>> > >> > > > > > >> with
>> >>>> > >> > > > > > >> > responses only errorCode, which looks very
>> limiting,
>> >>>> in case
>> >>>> > >> > of
>> >>>> > >> > > > CLI
>> >>>> > >> > > > > we
>> >>>> > >> > > > > > >> may
>> >>>> > >> > > > > > >> > want to print human readable error description.
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > So, taking into account previous item about
>> batching,
>> >>>> what
>> >>>> > >> do
>> >>>> > >> > > you
>> >>>> > >> > > > > > think
>> >>>> > >> > > > > > >> > about
>> >>>> > >> > > > > > >> > having smth like:
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > ('create' doesn't support regexp)
>> >>>> > >> > > > > > >> > CreateTopicRequest => TopicName Partitions
>> Replicas
>> >>>> > >> > > > > ReplicaAssignment
>> >>>> > >> > > > > > >> > [Config]
>> >>>> > >> > > > > > >> > CreateTopicResponse => ErrorCode ErrorDescription
>> >>>> > >> > > > > > >> > ErrorCode => int16
>> >>>> > >> > > > > > >> > ErrorDescription => string (empty if
>> successful)
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > AlterTopicRequest -> TopicNameRegexp Partitions
>> >>>> > >> > > ReplicaAssignment
>> >>>> > >> > > > > > >> > [AddedConfig] [DeletedConfig]
>> >>>> > >> > > > > > >> > AlterTopicResponse -> [TopicName ErrorCode
>> >>>> ErrorDescription]
>> >>>> > >> > > > > > >> > CommandErrorCode CommandErrorDescription
>> >>>> > >> > > > > > >> > CommandErrorCode => int16
>> >>>> > >> > > > > > >> > CommandErrorDescription => string (nonempty in
>> case
>> >>>> of
>> >>>> > >> fatal
>> >>>> > >> > > > > error,
>> >>>> > >> > > > > > >> e.g.
>> >>>> > >> > > > > > >> > we couldn't get topics by regexp)
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > DescribeTopicRequest -> TopicNameRegexp
>> >>>> > >> > > > > > >> > DescribeTopicResponse -> [TopicName
>> TopicDescription
>> >>>> > >> ErrorCode
>> >>>> > >> > > > > > >> > ErrorDescription] CommandErrorCode
>> >>>> CommandErrorDescription
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > Also, any thoughts about our discussion regarding
>> >>>> re-routing
>> >>>> > >> > > > > facility?
>> >>>> > >> > > > > > >> In
>> >>>> > >> > > > > > >> > my
>> >>>> > >> > > > > > >> > understanding, it is like between augmenting
>> >>>> > >> > > TopicMetadataRequest
>> >>>> > >> > > > > > >> > (to include at least controllerId) and
>> implementing
>> >>>> new
>> >>>> > >> > generic
>> >>>> > >> > > > > > >> re-routing
>> >>>> > >> > > > > > >> > facility so sending messages to controller will
>> be
>> >>>> handled
>> >>>> > >> by
>> >>>> > >> > > it.
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > Thanks,
>> >>>> > >> > > > > > >> > Andrii Biletskyi
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > On Mon, Feb 16, 2015 at 5:26 PM, Andrii
>> Biletskyi <
>> >>>> > >> > > > > > >> > andrii.bilets...@stealth.ly> wrote:
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > > @Guozhang:
>> >>>> > >> > > > > > >> > > Thanks for your comments, I've answered some of
>> >>>> those. The
>> >>>> > >> > > main
>> >>>> > >> > > > > > thing
>> >>>> > >> > > > > > >> is
>> >>>> > >> > > > > > >> > > having merged request for
>> >>>> create-alter-delete-describe - I
>> >>>> > >> > > have
>> >>>> > >> > > > > some
>> >>>> > >> > > > > > >> > > concerns about this approach.
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> > > @*Jay*:
>> >>>> > >> > > > > > >> > > I see that introduced ClusterMetadaRequest is
>> also
>> >>>> one of
>> >>>> > >> > the
>> >>>> > >> > > > > > >> concerns.
>> >>>> > >> > > > > > >> > We
>> >>>> > >> > > > > > >> > > can solve it if we implement re-routing
>> facility.
>> >>>> But I
>> >>>> > >> > agree
>> >>>> > >> > > > with
>> >>>> > >> > > > > > >> > > Guozhang - it will make clients' internals a
>> little
>> >>>> bit
>> >>>> > >> > easier
>> >>>> > >> > > > but
>> >>>> > >> > > > > > >> this
>> >>>> > >> > > > > > >> > > seems to be a complex logic to implement and
>> >>>> support then.
>> >>>> > >> > > > > > Especially
>> >>>> > >> > > > > > >> for
>> >>>> > >> > > > > > >> > > Fetch and Produce (even if we add re-routing
>> later
>> >>>> for
>> >>>> > >> these
>> >>>> > >> > > > > > >> requests).
>> >>>> > >> > > > > > >> > > Also people will tend to avoid this re-routing
>> >>>> facility
>> >>>> > >> and
>> >>>> > >> > > hold
>> >>>> > >> > > > > > local
>> >>>> > >> > > > > > >> > > cluster cache to ensure their high-priority
>> requests
>> >>>> > >> (which
>> >>>> > >> > > some
>> >>>> > >> > > > > of
>> >>>> > >> > > > > > >> the
>> >>>> > >> > > > > > >> > > admin requests are) not sent to some busy
>> broker
>> >>>> where
>> >>>> > >> they
>> >>>> > >> > > wait
>> >>>> > >> > > > > to
>> >>>> > >> > > > > > be
>> >>>> > >> > > > > > >> > > routed to the correct one.
>> >>>> > >> > > > > > >> > > As pointed out by Jun here (
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > >
>> >>>> > >> > > > >
>> >>>> > >> > > >
>> >>>> > >> > >
>> >>>> > >> >
>> >>>> > >>
>> >>>>
>> https://issues.apache.org/jira/browse/KAFKA-1772?focusedCommentId=14234530&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14234530
>> >>>> > >> > > > > > >> > )
>> >>>> > >> > > > > > >> > > to solve the issue we might introduce a message
>> >>>> type to
>> >>>> > >> get
>> >>>> > >> > > > > cluster
>> >>>> > >> > > > > > >> > state.
>> >>>> > >> > > > > > >> > > But I agree we can just update
>> >>>> TopicMetadataResponse to
>> >>>> > >> > > include
>> >>>> > >> > > > > > >> > > controllerId (and probably smth else).
>> >>>> > >> > > > > > >> > > What are you thougths?
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> > > Thanks,
>> >>>> > >> > > > > > >> > > Andrii
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> > > On Thu, Feb 12, 2015 at 8:31 AM, Guozhang Wang
>> <
>> >>>> > >> > > > > wangg...@gmail.com>
>> >>>> > >> > > > > > >> > wrote:
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> > >> I think for the topics commands we can
>> actually
>> >>>> merge
>> >>>> > >> > > > > > >> > >> create/alter/delete/describe as one request
>> type
>> >>>> since
>> >>>> > >> > their
>> >>>> > >> > > > > > formats
>> >>>> > >> > > > > > >> are
>> >>>> > >> > > > > > >> > >> very much similar, and keep list-topics and
>> others
>> >>>> like
>> >>>> > >> > > > > > >> > >> partition-reassignment /
>> preferred-leader-election
>> >>>> as
>> >>>> > >> > > separate
>> >>>> > >> > > > > > >> request
>> >>>> > >> > > > > > >> > >> types, I also left some other comments on the
>> RB (
>> >>>> > >> > > > > > >> > >> https://reviews.apache.org/r/29301/).
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> > >> On Wed, Feb 11, 2015 at 2:04 PM, Jay Kreps <
>> >>>> > >> > > > jay.kr...@gmail.com>
>> >>>> > >> > > > > > >> wrote:
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> > >> > Yeah I totally agree that we don't want to
>> just
>> >>>> have
>> >>>> > >> one
>> >>>> > >> > > "do
>> >>>> > >> > > > > > admin
>> >>>> > >> > > > > > >> > >> stuff"
>> >>>> > >> > > > > > >> > >> > command that has the union of all
>> parameters.
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >> > What I am saying is that command line tools
>> are
>> >>>> one
>> >>>> > >> > client
>> >>>> > >> > > of
>> >>>> > >> > > > > the
>> >>>> > >> > > > > > >> > >> > administrative apis, but these will be used
>> in a
>> >>>> number
>> >>>> > >> > of
>> >>>> > >> > > > > > >> scenarios
>> >>>> > >> > > > > > >> > so
>> >>>> > >> > > > > > >> > >> > they should make logical sense even in the
>> >>>> absence of
>> >>>> > >> the
>> >>>> > >> > > > > command
>> >>>> > >> > > > > > >> line
>> >>>> > >> > > > > > >> > >> > tool. Hence comments like trying to clarify
>> the
>> >>>> > >> > > relationship
>> >>>> > >> > > > > > >> between
>> >>>> > >> > > > > > >> > >> > ClusterMetadata and TopicMetadata...these
>> kinds
>> >>>> of
>> >>>> > >> things
>> >>>> > >> > > > > really
>> >>>> > >> > > > > > >> need
>> >>>> > >> > > > > > >> > >> to be
>> >>>> > >> > > > > > >> > >> > thought through.
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >> > Hope that makes sense.
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >> > -Jay
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >> > On Wed, Feb 11, 2015 at 1:41 PM, Andrii
>> >>>> Biletskyi <
>> >>>> > >> > > > > > >> > >> > andrii.bilets...@stealth.ly> wrote:
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >> > > Jay,
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> > > Thanks for answering. You understood
>> >>>> correctly, most
>> >>>> > >> of
>> >>>> > >> > > my
>> >>>> > >> > > > > > >> comments
>> >>>> > >> > > > > > >> > >> were
>> >>>> > >> > > > > > >> > >> > > related to your point 1) - about "well
>> >>>> thought-out"
>> >>>> > >> > apis.
>> >>>> > >> > > > > Also,
>> >>>> > >> > > > > > >> yes,
>> >>>> > >> > > > > > >> > >> as I
>> >>>> > >> > > > > > >> > >> > > understood we would like to introduce a
>> single
>> >>>> > >> unified
>> >>>> > >> > > CLI
>> >>>> > >> > > > > tool
>> >>>> > >> > > > > > >> with
>> >>>> > >> > > > > > >> > >> > > centralized server-side request handling
>> for
>> >>>> lots of
>> >>>> > >> > > > existing
>> >>>> > >> > > > > > >> ones
>> >>>> > >> > > > > > >> > >> (incl.
>> >>>> > >> > > > > > >> > >> > > TopicCommand, CommitOffsetChecker,
>> >>>> > >> ReassignPartitions,
>> >>>> > >> > > smth
>> >>>> > >> > > > > > else
>> >>>> > >> > > > > > >> if
>> >>>> > >> > > > > > >> > >> added
>> >>>> > >> > > > > > >> > >> > > in future). In our previous discussion (
>> >>>> > >> > > > > > >> > >> > >
>> >>>> https://issues.apache.org/jira/browse/KAFKA-1694)
>> >>>> > >> > people
>> >>>> > >> > > > > said
>> >>>> > >> > > > > > >> > they'd
>> >>>> > >> > > > > > >> > >> > > rather
>> >>>> > >> > > > > > >> > >> > > have a separate message for each command,
>> so,
>> >>>> yes,
>> >>>> > >> this
>> >>>> > >> > > > way I
>> >>>> > >> > > > > > >> came
>> >>>> > >> > > > > > >> > to
>> >>>> > >> > > > > > >> > >> 1-1
>> >>>> > >> > > > > > >> > >> > > mapping between commands in the tool and
>> >>>> protocol
>> >>>> > >> > > > additions.
>> >>>> > >> > > > > > But
>> >>>> > >> > > > > > >> I
>> >>>> > >> > > > > > >> > >> might
>> >>>> > >> > > > > > >> > >> > be
>> >>>> > >> > > > > > >> > >> > > wrong.
>> >>>> > >> > > > > > >> > >> > > At the end I just try to start discussion
>> how
>> >>>> at
>> >>>> > >> least
>> >>>> > >> > > > > > generally
>> >>>> > >> > > > > > >> > this
>> >>>> > >> > > > > > >> > >> > > protocol should look like.
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> > > Thanks,
>> >>>> > >> > > > > > >> > >> > > Andrii
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> > > On Wed, Feb 11, 2015 at 11:10 PM, Jay
>> Kreps <
>> >>>> > >> > > > > > jay.kr...@gmail.com
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >> > >> wrote:
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> > > > Hey Andrii,
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > To answer your earlier question we just
>> >>>> really
>> >>>> > >> can't
>> >>>> > >> > be
>> >>>> > >> > > > > > adding
>> >>>> > >> > > > > > >> any
>> >>>> > >> > > > > > >> > >> more
>> >>>> > >> > > > > > >> > >> > > > scala protocol objects. These things are
>> >>>> super hard
>> >>>> > >> > to
>> >>>> > >> > > > > > maintain
>> >>>> > >> > > > > > >> > >> because
>> >>>> > >> > > > > > >> > >> > > > they hand code the byte parsing and
>> don't
>> >>>> have good
>> >>>> > >> > > > > > versioning
>> >>>> > >> > > > > > >> > >> support.
>> >>>> > >> > > > > > >> > >> > > > Since we are already planning on
>> converting
>> >>>> we
>> >>>> > >> > > definitely
>> >>>> > >> > > > > > don't
>> >>>> > >> > > > > > >> > >> want to
>> >>>> > >> > > > > > >> > >> > > add
>> >>>> > >> > > > > > >> > >> > > > a ton more of these--they are total tech
>> >>>> debt.
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > What does it mean that the changes are
>> >>>> isolated
>> >>>> > >> from
>> >>>> > >> > > the
>> >>>> > >> > > > > > >> current
>> >>>> > >> > > > > > >> > >> code
>> >>>> > >> > > > > > >> > >> > > base?
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > I actually didn't understand the
>> remaining
>> >>>> > >> comments,
>> >>>> > >> > > > which
>> >>>> > >> > > > > of
>> >>>> > >> > > > > > >> the
>> >>>> > >> > > > > > >> > >> > points
>> >>>> > >> > > > > > >> > >> > > > are you responding to?
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > Maybe one sticking point here is that it
>> >>>> seems like
>> >>>> > >> > you
>> >>>> > >> > > > > want
>> >>>> > >> > > > > > to
>> >>>> > >> > > > > > >> > make
>> >>>> > >> > > > > > >> > >> > some
>> >>>> > >> > > > > > >> > >> > > > kind of tool, and you have made a 1-1
>> mapping
>> >>>> > >> between
>> >>>> > >> > > > > > commands
>> >>>> > >> > > > > > >> you
>> >>>> > >> > > > > > >> > >> > > imagine
>> >>>> > >> > > > > > >> > >> > > > in the tool and protocol additions. I
>> want
>> >>>> to make
>> >>>> > >> > sure
>> >>>> > >> > > > we
>> >>>> > >> > > > > > >> don't
>> >>>> > >> > > > > > >> > do
>> >>>> > >> > > > > > >> > >> > that.
>> >>>> > >> > > > > > >> > >> > > > The protocol needs to be really really
>> well
>> >>>> thought
>> >>>> > >> > out
>> >>>> > >> > > > > > against
>> >>>> > >> > > > > > >> > many
>> >>>> > >> > > > > > >> > >> > use
>> >>>> > >> > > > > > >> > >> > > > cases so it should make perfect logical
>> >>>> sense in
>> >>>> > >> the
>> >>>> > >> > > > > absence
>> >>>> > >> > > > > > of
>> >>>> > >> > > > > > >> > >> knowing
>> >>>> > >> > > > > > >> > >> > > the
>> >>>> > >> > > > > > >> > >> > > > command line tool, right?
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > -Jay
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > On Wed, Feb 11, 2015 at 11:57 AM, Andrii
>> >>>> Biletskyi
>> >>>> > >> <
>> >>>> > >> > > > > > >> > >> > > > andrii.bilets...@stealth.ly> wrote:
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > > Hey Jay,
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > I would like to continue this
>> discussion
>> >>>> as it
>> >>>> > >> seem
>> >>>> > >> > > > there
>> >>>> > >> > > > > > is
>> >>>> > >> > > > > > >> no
>> >>>> > >> > > > > > >> > >> > > progress
>> >>>> > >> > > > > > >> > >> > > > > here.
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > First of all, could you please explain
>> >>>> what did
>> >>>> > >> you
>> >>>> > >> > > > mean
>> >>>> > >> > > > > in
>> >>>> > >> > > > > > >> 2?
>> >>>> > >> > > > > > >> > How
>> >>>> > >> > > > > > >> > >> > > > exactly
>> >>>> > >> > > > > > >> > >> > > > > are we going to migrate to the new
>> java
>> >>>> protocol
>> >>>> > >> > > > > > definitions.
>> >>>> > >> > > > > > >> > And
>> >>>> > >> > > > > > >> > >> why
>> >>>> > >> > > > > > >> > >> > > > it's
>> >>>> > >> > > > > > >> > >> > > > > a blocker for centralized CLI?
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > I agree with you, this feature
>> includes
>> >>>> lots of
>> >>>> > >> > > stuff,
>> >>>> > >> > > > > but
>> >>>> > >> > > > > > >> > >> thankfully
>> >>>> > >> > > > > > >> > >> > > > > almost all changes are isolated from
>> the
>> >>>> current
>> >>>> > >> > code
>> >>>> > >> > > > > base,
>> >>>> > >> > > > > > >> > >> > > > > so the main thing, I think, we need to
>> >>>> agree is
>> >>>> > >> > RQ/RP
>> >>>> > >> > > > > > format.
>> >>>> > >> > > > > > >> > >> > > > > So how can we start discussion about
>> the
>> >>>> concrete
>> >>>> > >> > > > > messages
>> >>>> > >> > > > > > >> > format?
>> >>>> > >> > > > > > >> > >> > > > > Can we take (
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > >
>> >>>> > >> > > > >
>> >>>> > >> > > >
>> >>>> > >> > >
>> >>>> > >> >
>> >>>> > >>
>> >>>>
>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-ProposedRQ/RPFormat
>> >>>> > >> > > > > > >> > >> > > > > )
>> >>>> > >> > > > > > >> > >> > > > > as starting point?
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > We had some doubts earlier whether it
>> worth
>> >>>> > >> > > introducing
>> >>>> > >> > > > > one
>> >>>> > >> > > > > > >> > >> generic
>> >>>> > >> > > > > > >> > >> > > Admin
>> >>>> > >> > > > > > >> > >> > > > > Request for all commands (
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> https://issues.apache.org/jira/browse/KAFKA-1694
>> >>>> > >> > > > > > >> > >> > > > > )
>> >>>> > >> > > > > > >> > >> > > > > but then everybody agreed it would be
>> >>>> better to
>> >>>> > >> > have
>> >>>> > >> > > > > > separate
>> >>>> > >> > > > > > >> > >> message
>> >>>> > >> > > > > > >> > >> > > for
>> >>>> > >> > > > > > >> > >> > > > > each admin command. The Request part
>> is
>> >>>> really
>> >>>> > >> > > dictated
>> >>>> > >> > > > > > from
>> >>>> > >> > > > > > >> the
>> >>>> > >> > > > > > >> > >> > > command
>> >>>> > >> > > > > > >> > >> > > > > (e.g. TopicCommand) arguments itself,
>> so
>> >>>> the
>> >>>> > >> > proposed
>> >>>> > >> > > > > > version
>> >>>> > >> > > > > > >> > >> should
>> >>>> > >> > > > > > >> > >> > be
>> >>>> > >> > > > > > >> > >> > > > > fine (let's put aside for now remarks
>> about
>> >>>> > >> > Optional
>> >>>> > >> > > > > type,
>> >>>> > >> > > > > > >> > >> batching,
>> >>>> > >> > > > > > >> > >> > > > > configs normalization - I agree with
>> all of
>> >>>> > >> them).
>> >>>> > >> > > > > > >> > >> > > > > So the second part is Response. I see
>> >>>> there are
>> >>>> > >> two
>> >>>> > >> > > > cases
>> >>>> > >> > > > > > >> here.
>> >>>> > >> > > > > > >> > >> > > > > a) "Mutate" requests -
>> Create/Alter/... ;
>> >>>> b)
>> >>>> > >> "Get"
>> >>>> > >> > > > > > requests -
>> >>>> > >> > > > > > >> > >> > > > > List/Describe...
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > a) should only hold request result
>> >>>> (regardless
>> >>>> > >> what
>> >>>> > >> > > we
>> >>>> > >> > > > > > decide
>> >>>> > >> > > > > > >> > >> about
>> >>>> > >> > > > > > >> > >> > > > > blocking/non-blocking commands
>> execution).
>> >>>> > >> > > > > > >> > >> > > > > Usually we provide error code in
>> response
>> >>>> but
>> >>>> > >> since
>> >>>> > >> > > we
>> >>>> > >> > > > > will
>> >>>> > >> > > > > > >> use
>> >>>> > >> > > > > > >> > >> this
>> >>>> > >> > > > > > >> > >> > in
>> >>>> > >> > > > > > >> > >> > > > > interactive shell we need some human
>> >>>> readable
>> >>>> > >> error
>> >>>> > >> > > > > > >> description
>> >>>> > >> > > > > > >> > -
>> >>>> > >> > > > > > >> > >> so
>> >>>> > >> > > > > > >> > >> > I
>> >>>> > >> > > > > > >> > >> > > > > added errorDesription field where you
>> can
>> >>>> at
>> >>>> > >> least
>> >>>> > >> > > > leave
>> >>>> > >> > > > > > >> > >> > > > > exception.getMessage.
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > b) in addition to previous item
>> message
>> >>>> should
>> >>>> > >> hold
>> >>>> > >> > > > > command
>> >>>> > >> > > > > > >> > >> specific
>> >>>> > >> > > > > > >> > >> > > > > response data. We can discuss in
>> detail
>> >>>> each of
>> >>>> > >> > them
>> >>>> > >> > > > but
>> >>>> > >> > > > > > >> let's
>> >>>> > >> > > > > > >> > for
>> >>>> > >> > > > > > >> > >> > now
>> >>>> > >> > > > > > >> > >> > > > > agree about the overall pattern.
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > Thanks,
>> >>>> > >> > > > > > >> > >> > > > > Andrii Biletskyi
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > On Fri, Jan 23, 2015 at 6:59 AM, Jay
>> Kreps
>> >>>> <
>> >>>> > >> > > > > > >> jay.kr...@gmail.com
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> > >> > > wrote:
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > > > > Hey Joe,
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > This is great. A few comments on
>> KIP-4
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 1. This is much needed
>> functionality,
>> >>>> but there
>> >>>> > >> > > are a
>> >>>> > >> > > > > lot
>> >>>> > >> > > > > > >> of
>> >>>> > >> > > > > > >> > >> the so
>> >>>> > >> > > > > > >> > >> > > > let's
>> >>>> > >> > > > > > >> > >> > > > > > really think these protocols
>> through. We
>> >>>> really
>> >>>> > >> > > want
>> >>>> > >> > > > to
>> >>>> > >> > > > > > >> end up
>> >>>> > >> > > > > > >> > >> > with a
>> >>>> > >> > > > > > >> > >> > > > set
>> >>>> > >> > > > > > >> > >> > > > > > of well thought-out, orthoganol
>> apis.
>> >>>> For this
>> >>>> > >> > > > reason I
>> >>>> > >> > > > > > >> think
>> >>>> > >> > > > > > >> > >> it is
>> >>>> > >> > > > > > >> > >> > > > > really
>> >>>> > >> > > > > > >> > >> > > > > > important to think through the end
>> state
>> >>>> even
>> >>>> > >> if
>> >>>> > >> > > that
>> >>>> > >> > > > > > >> includes
>> >>>> > >> > > > > > >> > >> APIs
>> >>>> > >> > > > > > >> > >> > > we
>> >>>> > >> > > > > > >> > >> > > > > > won't implement in the first phase.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 2. Let's please please please wait
>> until
>> >>>> we
>> >>>> > >> have
>> >>>> > >> > > > > switched
>> >>>> > >> > > > > > >> the
>> >>>> > >> > > > > > >> > >> > server
>> >>>> > >> > > > > > >> > >> > > > over
>> >>>> > >> > > > > > >> > >> > > > > > to the new java protocol
>> definitions. If
>> >>>> we add
>> >>>> > >> > > > upteen
>> >>>> > >> > > > > > >> more ad
>> >>>> > >> > > > > > >> > >> hoc
>> >>>> > >> > > > > > >> > >> > > > scala
>> >>>> > >> > > > > > >> > >> > > > > > objects that is just generating more
>> >>>> work for
>> >>>> > >> the
>> >>>> > >> > > > > > >> conversion
>> >>>> > >> > > > > > >> > we
>> >>>> > >> > > > > > >> > >> > know
>> >>>> > >> > > > > > >> > >> > > we
>> >>>> > >> > > > > > >> > >> > > > > > have to do.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 3. This proposal introduces a new
>> type of
>> >>>> > >> > optional
>> >>>> > >> > > > > > >> parameter.
>> >>>> > >> > > > > > >> > >> This
>> >>>> > >> > > > > > >> > >> > is
>> >>>> > >> > > > > > >> > >> > > > > > inconsistent with everything else
>> in the
>> >>>> > >> protocol
>> >>>> > >> > > > where
>> >>>> > >> > > > > > we
>> >>>> > >> > > > > > >> use
>> >>>> > >> > > > > > >> > >> -1
>> >>>> > >> > > > > > >> > >> > or
>> >>>> > >> > > > > > >> > >> > > > some
>> >>>> > >> > > > > > >> > >> > > > > > other marker value. You could argue
>> >>>> either way
>> >>>> > >> > but
>> >>>> > >> > > > > let's
>> >>>> > >> > > > > > >> stick
>> >>>> > >> > > > > > >> > >> with
>> >>>> > >> > > > > > >> > >> > > > that
>> >>>> > >> > > > > > >> > >> > > > > > for consistency. For clients that
>> >>>> implemented
>> >>>> > >> the
>> >>>> > >> > > > > > protocol
>> >>>> > >> > > > > > >> in
>> >>>> > >> > > > > > >> > a
>> >>>> > >> > > > > > >> > >> > > better
>> >>>> > >> > > > > > >> > >> > > > > way
>> >>>> > >> > > > > > >> > >> > > > > > than our scala code these basic
>> >>>> primitives are
>> >>>> > >> > hard
>> >>>> > >> > > > to
>> >>>> > >> > > > > > >> change.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 4. ClusterMetadata: This seems to
>> >>>> duplicate
>> >>>> > >> > > > > > >> > TopicMetadataRequest
>> >>>> > >> > > > > > >> > >> > > which
>> >>>> > >> > > > > > >> > >> > > > > has
>> >>>> > >> > > > > > >> > >> > > > > > brokers, topics, and partitions. I
>> think
>> >>>> we
>> >>>> > >> > should
>> >>>> > >> > > > > rename
>> >>>> > >> > > > > > >> that
>> >>>> > >> > > > > > >> > >> > > request
>> >>>> > >> > > > > > >> > >> > > > > > ClusterMetadataRequest (or just
>> >>>> > >> MetadataRequest)
>> >>>> > >> > > and
>> >>>> > >> > > > > > >> include
>> >>>> > >> > > > > > >> > >> the id
>> >>>> > >> > > > > > >> > >> > > of
>> >>>> > >> > > > > > >> > >> > > > > the
>> >>>> > >> > > > > > >> > >> > > > > > controller. Or are there other
>> things we
>> >>>> could
>> >>>> > >> > add
>> >>>> > >> > > > > here?
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 5. We have a tendency to try to
>> make a
>> >>>> lot of
>> >>>> > >> > > > requests
>> >>>> > >> > > > > > that
>> >>>> > >> > > > > > >> > can
>> >>>> > >> > > > > > >> > >> > only
>> >>>> > >> > > > > > >> > >> > > go
>> >>>> > >> > > > > > >> > >> > > > > to
>> >>>> > >> > > > > > >> > >> > > > > > particular nodes. This adds a lot of
>> >>>> burden for
>> >>>> > >> > > > client
>> >>>> > >> > > > > > >> > >> > > implementations
>> >>>> > >> > > > > > >> > >> > > > > (it
>> >>>> > >> > > > > > >> > >> > > > > > sounds easy but each discovery can
>> fail
>> >>>> in many
>> >>>> > >> > > parts
>> >>>> > >> > > > > so
>> >>>> > >> > > > > > it
>> >>>> > >> > > > > > >> > >> ends up
>> >>>> > >> > > > > > >> > >> > > > > being a
>> >>>> > >> > > > > > >> > >> > > > > > full state machine to do right). I
>> think
>> >>>> we
>> >>>> > >> > should
>> >>>> > >> > > > > > consider
>> >>>> > >> > > > > > >> > >> making
>> >>>> > >> > > > > > >> > >> > > > admin
>> >>>> > >> > > > > > >> > >> > > > > > commands and ideally as many of the
>> >>>> other apis
>> >>>> > >> as
>> >>>> > >> > > > > > possible
>> >>>> > >> > > > > > >> > >> > available
>> >>>> > >> > > > > > >> > >> > > on
>> >>>> > >> > > > > > >> > >> > > > > all
>> >>>> > >> > > > > > >> > >> > > > > > brokers and just redirect to the
>> >>>> controller on
>> >>>> > >> > the
>> >>>> > >> > > > > broker
>> >>>> > >> > > > > > >> > side.
>> >>>> > >> > > > > > >> > >> > > Perhaps
>> >>>> > >> > > > > > >> > >> > > > > > there would be a general way to
>> >>>> encapsulate
>> >>>> > >> this
>> >>>> > >> > > > > > re-routing
>> >>>> > >> > > > > > >> > >> > behavior.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 6. We should probably normalize the
>> key
>> >>>> value
>> >>>> > >> > pairs
>> >>>> > >> > > > > used
>> >>>> > >> > > > > > >> for
>> >>>> > >> > > > > > >> > >> > configs
>> >>>> > >> > > > > > >> > >> > > > > rather
>> >>>> > >> > > > > > >> > >> > > > > > than embedding a new formatting. So
>> two
>> >>>> strings
>> >>>> > >> > > > rather
>> >>>> > >> > > > > > than
>> >>>> > >> > > > > > >> > one
>> >>>> > >> > > > > > >> > >> > with
>> >>>> > >> > > > > > >> > >> > > an
>> >>>> > >> > > > > > >> > >> > > > > > internal equals sign.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 7. Is the postcondition of these
>> APIs
>> >>>> that the
>> >>>> > >> > > > command
>> >>>> > >> > > > > > has
>> >>>> > >> > > > > > >> > >> begun or
>> >>>> > >> > > > > > >> > >> > > > that
>> >>>> > >> > > > > > >> > >> > > > > > the command has been completed? It
>> is a
>> >>>> lot
>> >>>> > >> more
>> >>>> > >> > > > usable
>> >>>> > >> > > > > > if
>> >>>> > >> > > > > > >> the
>> >>>> > >> > > > > > >> > >> > > command
>> >>>> > >> > > > > > >> > >> > > > > has
>> >>>> > >> > > > > > >> > >> > > > > > been completed so you know that if
>> you
>> >>>> create a
>> >>>> > >> > > topic
>> >>>> > >> > > > > and
>> >>>> > >> > > > > > >> then
>> >>>> > >> > > > > > >> > >> > > publish
>> >>>> > >> > > > > > >> > >> > > > to
>> >>>> > >> > > > > > >> > >> > > > > > it you won't get an exception about
>> >>>> there being
>> >>>> > >> > no
>> >>>> > >> > > > such
>> >>>> > >> > > > > > >> topic.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 8. Describe topic and list topics
>> >>>> duplicate a
>> >>>> > >> lot
>> >>>> > >> > > of
>> >>>> > >> > > > > > stuff
>> >>>> > >> > > > > > >> in
>> >>>> > >> > > > > > >> > >> the
>> >>>> > >> > > > > > >> > >> > > > > metadata
>> >>>> > >> > > > > > >> > >> > > > > > request. Is there a reason to give
>> back
>> >>>> topics
>> >>>> > >> > > marked
>> >>>> > >> > > > > for
>> >>>> > >> > > > > > >> > >> > deletion? I
>> >>>> > >> > > > > > >> > >> > > > > feel
>> >>>> > >> > > > > > >> > >> > > > > > like if we just make the
>> post-condition
>> >>>> of the
>> >>>> > >> > > delete
>> >>>> > >> > > > > > >> command
>> >>>> > >> > > > > > >> > be
>> >>>> > >> > > > > > >> > >> > that
>> >>>> > >> > > > > > >> > >> > > > the
>> >>>> > >> > > > > > >> > >> > > > > > topic is deleted that will get rid
>> of
>> >>>> the need
>> >>>> > >> > for
>> >>>> > >> > > > this
>> >>>> > >> > > > > > >> right?
>> >>>> > >> > > > > > >> > >> And
>> >>>> > >> > > > > > >> > >> > it
>> >>>> > >> > > > > > >> > >> > > > > will
>> >>>> > >> > > > > > >> > >> > > > > > be much more intuitive.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 9. Should we consider batching these
>> >>>> requests?
>> >>>> > >> We
>> >>>> > >> > > > have
>> >>>> > >> > > > > > >> > generally
>> >>>> > >> > > > > > >> > >> > > tried
>> >>>> > >> > > > > > >> > >> > > > to
>> >>>> > >> > > > > > >> > >> > > > > > allow multiple operations to be
>> batched.
>> >>>> My
>> >>>> > >> > > suspicion
>> >>>> > >> > > > > is
>> >>>> > >> > > > > > >> that
>> >>>> > >> > > > > > >> > >> > without
>> >>>> > >> > > > > > >> > >> > > > > this
>> >>>> > >> > > > > > >> > >> > > > > > we will get a lot of code that does
>> >>>> something
>> >>>> > >> > like
>> >>>> > >> > > > > > >> > >> > > > > > for(topic:
>> adminClient.listTopics())
>> >>>> > >> > > > > > >> > >> > > > > >
>> adminClient.describeTopic(topic)
>> >>>> > >> > > > > > >> > >> > > > > > this code will work great when you
>> test
>> >>>> on 5
>> >>>> > >> > topics
>> >>>> > >> > > > but
>> >>>> > >> > > > > > >> not do
>> >>>> > >> > > > > > >> > >> as
>> >>>> > >> > > > > > >> > >> > > well
>> >>>> > >> > > > > > >> > >> > > > if
>> >>>> > >> > > > > > >> > >> > > > > > you have 50k.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 10. I think we should also discuss
>> how
>> >>>> we want
>> >>>> > >> to
>> >>>> > >> > > > > expose
>> >>>> > >> > > > > > a
>> >>>> > >> > > > > > >> > >> > > programmatic
>> >>>> > >> > > > > > >> > >> > > > > JVM
>> >>>> > >> > > > > > >> > >> > > > > > client api for these operations.
>> >>>> Currently
>> >>>> > >> people
>> >>>> > >> > > > rely
>> >>>> > >> > > > > on
>> >>>> > >> > > > > > >> > >> > AdminUtils
>> >>>> > >> > > > > > >> > >> > > > > which
>> >>>> > >> > > > > > >> > >> > > > > > is totally sketchy. I think we
>> probably
>> >>>> need
>> >>>> > >> > > another
>> >>>> > >> > > > > > client
>> >>>> > >> > > > > > >> > >> under
>> >>>> > >> > > > > > >> > >> > > > > clients/
>> >>>> > >> > > > > > >> > >> > > > > > that exposes administrative
>> >>>> functionality. We
>> >>>> > >> > will
>> >>>> > >> > > > need
>> >>>> > >> > > > > > >> this
>> >>>> > >> > > > > > >> > >> just
>> >>>> > >> > > > > > >> > >> > to
>> >>>> > >> > > > > > >> > >> > > > > > properly test the new apis, I
>> suspect. We
>> >>>> > >> should
>> >>>> > >> > > > figure
>> >>>> > >> > > > > > out
>> >>>> > >> > > > > > >> > that
>> >>>> > >> > > > > > >> > >> > API.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > 11. The other information that
>> would be
>> >>>> really
>> >>>> > >> > > useful
>> >>>> > >> > > > > to
>> >>>> > >> > > > > > >> get
>> >>>> > >> > > > > > >> > >> would
>> >>>> > >> > > > > > >> > >> > be
>> >>>> > >> > > > > > >> > >> > > > > > information about partitions--how
>> much
>> >>>> data is
>> >>>> > >> in
>> >>>> > >> > > the
>> >>>> > >> > > > > > >> > partition,
>> >>>> > >> > > > > > >> > >> > what
>> >>>> > >> > > > > > >> > >> > > > are
>> >>>> > >> > > > > > >> > >> > > > > > the segment offsets, what is the
>> log-end
>> >>>> offset
>> >>>> > >> > > (i.e.
>> >>>> > >> > > > > > last
>> >>>> > >> > > > > > >> > >> offset),
>> >>>> > >> > > > > > >> > >> > > > what
>> >>>> > >> > > > > > >> > >> > > > > is
>> >>>> > >> > > > > > >> > >> > > > > > the compaction point, etc. I think
>> that
>> >>>> done
>> >>>> > >> > right
>> >>>> > >> > > > this
>> >>>> > >> > > > > > >> would
>> >>>> > >> > > > > > >> > be
>> >>>> > >> > > > > > >> > >> > the
>> >>>> > >> > > > > > >> > >> > > > > > successor to the very awkward
>> >>>> OffsetRequest we
>> >>>> > >> > have
>> >>>> > >> > > > > > today.
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > -Jay
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > On Wed, Jan 21, 2015 at 10:27 PM,
>> Joe
>> >>>> Stein <
>> >>>> > >> > > > > > >> > >> joe.st...@stealth.ly>
>> >>>> > >> > > > > > >> > >> > > > > wrote:
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > > Hi, created a KIP
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > >
>> >>>> > >> > > > >
>> >>>> > >> > > >
>> >>>> > >> > >
>> >>>> > >> >
>> >>>> > >>
>> >>>>
>> https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > > JIRA
>> >>>> > >> > > > > https://issues.apache.org/jira/browse/KAFKA-1694
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> /*******************************************
>> >>>> > >> > > > > > >> > >> > > > > > > Joe Stein
>> >>>> > >> > > > > > >> > >> > > > > > > Founder, Principal Consultant
>> >>>> > >> > > > > > >> > >> > > > > > > Big Data Open Source Security LLC
>> >>>> > >> > > > > > >> > >> > > > > > > http://www.stealth.ly
>> >>>> > >> > > > > > >> > >> > > > > > > Twitter: @allthingshadoop <
>> >>>> > >> > > > > > >> > >> > http://www.twitter.com/allthingshadoop
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> ********************************************/
>> >>>> > >> > > > > > >> > >> > > > > > >
>> >>>> > >> > > > > > >> > >> > > > > >
>> >>>> > >> > > > > > >> > >> > > > >
>> >>>> > >> > > > > > >> > >> > > >
>> >>>> > >> > > > > > >> > >> > >
>> >>>> > >> > > > > > >> > >> >
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> > >> --
>> >>>> > >> > > > > > >> > >> -- Guozhang
>> >>>> > >> > > > > > >> > >>
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> > >
>> >>>> > >> > > > > > >> >
>> >>>> > >> > > > > > >>
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > > >
>> >>>> > >> > > > > >
>> >>>> > >> > > > >
>> >>>> > >> > > >
>> >>>> > >> > >
>> >>>> > >> >
>> >>>> > >> >
>> >>>> > >> >
>> >>>> > >> > --
>> >>>> > >> > Jeff Holoman
>> >>>> > >> > Systems Engineer
>> >>>> > >> >
>> >>>> > >>
>> >>>>
>> >>>>
>> >>>
>> >>>
>> >>> --
>> >>> -- Guozhang
>> >>>
>> >>
>> >>
>> >>
>> >> --
>> >> -- Guozhang
>>
>
>
