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
