Gwen,
On your second point. Can you describe a usecase where
mutliple clients ended up sharing a producer and even if they
do why can't they not use single token that producer
captures. Why would we need multiple clients with different
tokens sharing a single instance of producer. Also in this
case other clients have access all the tokens no?
Thanks,
Harsha
On Tue, May 3, 2016, at 11:49 AM, Gwen Shapira wrote:
> Sorry for the delay:
>
> Two questions that we didn't see in the wiki:
> 1. Is there an expiration for delegation tokens? Renewal? How do we
> revoke them?
> 2. If we want to use delegation tokens for "do-as" (say, submit Storm
> job as my user), we will need a producer for every job (we can't share
> them between multiple jobs running on same node), since we only
> authenticate when connecting. Is there a plan to change this for
> delegation tokens, in order to allow multiple users with different
> tokens to share a client?
>
> Gwen
>
> On Tue, May 3, 2016 at 9:12 AM, parth brahmbhatt
> <brahmbhatt.pa...@gmail.com> wrote:
> > Bumping this up one more time, can other committers review?
> >
> > Thanks
> > Parth
> >
> > On Tue, Apr 26, 2016 at 9:07 AM, Harsha <ka...@harsha.io> wrote:
> >
> >> Parth,
> >> Overall current design looks good to me. I am +1 on the KIP.
> >>
> >> Gwen , Jun can you review this as well.
> >>
> >> -Harsha
> >>
> >> On Tue, Apr 19, 2016, at 09:57 AM, parth brahmbhatt wrote:
> >> > Thanks for review Jitendra.
> >> >
> >> > I don't like the idea of infinite lifetime but I see the Streaming use
> >> > case. Even for Streaming use case I was hoping there will be some notion
> >> > of
> >> > master/driver that can get new delegation tokens at fixed interval and
> >> > distribute to workers. If that is not the case for we can discuss
> >> > delegation tokens renewing them self and the security implications of the
> >> > same.
> >> >
> >> > I did not want clients to fetch tokens from zookeeper, overall I think
> >> > its
> >> > better if clients don't rely on our metadata store and I think we are
> >> > moving in that direction with all the KIP-4 improvements. I chose
> >> > zookeeper as in this case the client will still just talk to broker , its
> >> > the brokers that will use zookeeper which we already do for a lot of
> >> > other
> >> > usecases + ease of development + and the ability so tokens will survive
> >> > even a rolling restart/cluster failure. if a majority agrees the added
> >> > complexity to have controller forwarding keys to all broker is justified
> >> > as
> >> > it provides tighter security , I am fine with that option too.
> >> >
> >> > Given zookeeper does not support SSL we can not store master keys in
> >> > zookeeper as master keys will be exposed on wire. To support rotation
> >> > without affecting current clients is something I need to put more thought
> >> > in. My current proposal assumes the rotation will invalidate all current
> >> > tokens.
> >> >
> >> > I request committers to also review and post their comments so we can
> >> > make
> >> > progress on this KIP.
> >> >
> >> > Thanks
> >> > Parth
> >> >
> >> > On Tue, Apr 19, 2016 at 8:39 AM, Ashish Singh <asi...@cloudera.com>
> >> > wrote:
> >> >
> >> > > On Mon, Apr 18, 2016 at 11:26 AM, Harsha <ka...@harsha.io> wrote:
> >> > >
> >> > > > Unifying the two discussion threads on this KIP.
> >> > > >
> >> > > > Here is the response from Jitendra
> >> > > >
> >> > > > "The need for a large number of clients that are running all over the
> >> > > > cluster that authenticate with Kafka brokers, is very similar to the
> >> > > > Hadoop use case of large number of tasks running across the cluster
> >> that
> >> > > > need authentication to Hdfs Namenode. Therefore, the delegation token
> >> > > > approach does seem like a good fit for this use case as we have seen
> >> it
> >> > > > working at large scale in HDFS and YARN.
> >> > > >
> >> > > > The proposed design is very much inline with Hadoop approach. A few
> >> > > > comments:
> >> > > >
> >> > > > 1) Why do you guys want to allow infinite renewable lifetime for a
> >> > > > token? HDFS restricts a token to a max life time (default 7 days). A
> >> > > > token's vulnerability is believed to increase with time.
> >> > > >
> >> > > I agree that having infinite lifetime might not be the best idea.
> >> > >
> >> > > >
> >> > > > 2) As I understand the tokens are stored in zookeeper as well, and
> >> can
> >> > > > be updated there. This is clever as it can allow replacing the tokens
> >> > > > once they run out of max life time, and clients can download new
> >> tokens
> >> > > > from zookeeper. It shouldn't be a big load on zookeeper as a client
> >> will
> >> > > > need to get a new token once in several days. In this approach you
> >> don't
> >> > > > need infinite lifetime on the token even for long running clients.
> >> > > >
> >> > > > 3) The token password are generated using a master key. The master
> >> key
> >> > > > should also be periodically changed. In Hadoop, the default renewal
> >> > > > period is 1 day.?
> >> > > >
> >> > > IIUC, this will require brokers maintaining a list of X most recent
> >> master
> >> > > keys. This list will have to be persisted somewhere, as if a broker
> >> goes
> >> > > down it will have to get that list again and storing master keys on ZK
> >> is
> >> > > not the best idea. However, if a broker goes down then we have much
> >> bigger
> >> > > issue to deal with and client can always re-authenticate is such
> >> events.
> >> > >
> >> > > Did you happen to take a look at other alternatives this list has
> >> > > suggested?
> >> > >
> >> > > >
> >> > > > Thanks for a thorough proposal, great work!"
> >> > > >
> >> > > >
> >> > > >
> >> > > > On Mon, Mar 7, 2016, at 10:28 PM, Gwen Shapira wrote:
> >> > > > > Makes sense to me. Thanks!
> >> > > > >
> >> > > > > On Mon, Mar 7, 2016 at 9:25 PM, Harsha <ka...@harsha.io> wrote:
> >> > > > > > It doesn't need any release vehicle but still the work can move
> >> > > > forward.
> >> > > > > > If anyone is interested in the KIP please do the review and
> >> provide
> >> > > the
> >> > > > > > comments.
> >> > > > > >
> >> > > > > > -Harsha
> >> > > > > >
> >> > > > > > On Mon, Mar 7, 2016, at 04:59 PM, Ismael Juma wrote:
> >> > > > > >> I agree that it would be good to have more time to review and
> >> > > discuss
> >> > > > > >> KIP-48.
> >> > > > > >>
> >> > > > > >> Ismael
> >> > > > > >>
> >> > > > > >> On Tue, Mar 8, 2016 at 12:55 AM, Gwen Shapira <
> >> g...@confluent.io>
> >> > > > wrote:
> >> > > > > >>
> >> > > > > >> > Hi Team,
> >> > > > > >> >
> >> > > > > >> > Since KIP-48 depends on KIP-43, which is already a bit of a
> >> risk
> >> > > for
> >> > > > > >> > the next release - any chance we can delay delegation tokens
> >> to
> >> > > > Kafka
> >> > > > > >> > 0.10.1?
> >> > > > > >> > With the community working on a release every 3 month, this
> >> is not
> >> > > > a huge
> >> > > > > >> > delay.
> >> > > > > >> >
> >> > > > > >> > Gwen
> >> > > > > >> >
> >> > > > > >> > On Fri, Feb 26, 2016 at 5:11 PM, Ashish Singh <
> >> > > asi...@cloudera.com>
> >> > > > wrote:
> >> > > > > >> > > Parth,
> >> > > > > >> > >
> >> > > > > >> > > Thanks again for the awesome write up. Following our
> >> discussion
> >> > > > from the
> >> > > > > >> > > JIRA, I think it will be easier to compare various
> >> alternatives
> >> > > > if they
> >> > > > > >> > are
> >> > > > > >> > > listed together. I am stating below a few alternatives along
> >> > > with
> >> > > > a the
> >> > > > > >> > > current proposal.
> >> > > > > >> > > (Current proposal) Store Delegation Token, DT, on ZK.
> >> > > > > >> > >
> >> > > > > >> > > 1. Client authenticates with a broker.
> >> > > > > >> > > 2. Once a client is authenticated, it will make a broker
> >> side
> >> > > > call to
> >> > > > > >> > > issue a delegation token.
> >> > > > > >> > > 3. The broker generates a shared secret based on
> >> > > HMAC-SHA256(a
> >> > > > > >> > > Password/Secret shared between all brokers, randomly
> >> > > generated
> >> > > > > >> > tokenId).
> >> > > > > >> > > 4. Broker stores this token in its in memory cache.
> >> Broker
> >> > > > also stores
> >> > > > > >> > > the DelegationToken without the hmac in the zookeeper.
> >> > > > > >> > > 5. All brokers will have a cache backed by zookeeper so
> >> they
> >> > > > will all
> >> > > > > >> > > get notified whenever a new token is generated and they
> >> will
> >> > > > update
> >> > > > > >> > their
> >> > > > > >> > > local cache whenever token state changes.
> >> > > > > >> > > 6. Broker returns the token to Client.
> >> > > > > >> > >
> >> > > > > >> > > Probable issues and fixes
> >> > > > > >> > >
> >> > > > > >> > > 1. Probable race condition, client tries to authenticate
> >> with
> >> > > > a broker
> >> > > > > >> > > that is yet to be updated with the newly generated DT.
> >> This
> >> > > can
> >> > > > > >> > probably be
> >> > > > > >> > > dealt with making dtRequest block until all brokers have
> >> > > > updated
> >> > > > > >> > their DT
> >> > > > > >> > > cache. Zk barrier or similar mechanism can be used.
> >> However,
> >> > > > all such
> >> > > > > >> > > mechanisms will increase complexity.
> >> > > > > >> > > 2. Using a static secret key from config file. Will
> >> require
> >> > > yet
> >> > > > > >> > another
> >> > > > > >> > > config and uses a static secret key. It is advised to
> >> rotate
> >> > > > secret
> >> > > > > >> > keys
> >> > > > > >> > > periodically. This can be avoided with controller
> >> generating
> >> > > > > >> > secretKey and
> >> > > > > >> > > passing to brokers periodically. However, this will
> >> require
> >> > > > brokers to
> >> > > > > >> > > maintain certain counts of secretKeys.
> >> > > > > >> > >
> >> > > > > >> > > (Alternative 1) Have controller generate delegation token.
> >> > > > > >> > >
> >> > > > > >> > > 1. Client authenticates with a broker.
> >> > > > > >> > > 2. Once a client is authenticated, it will make a broker
> >> side
> >> > > > call to
> >> > > > > >> > > issue a delegation token.
> >> > > > > >> > > 3. Broker forwards the request to controller.
> >> > > > > >> > > 4. Controller generates a DT and broadcasts to all
> >> brokers.
> >> > > > > >> > > 5. Broker stores this token in its memory cache.
> >> > > > > >> > > 6. Controller responds to broker’s DT req.
> >> > > > > >> > > 7. Broker returns the token to Client.
> >> > > > > >> > >
> >> > > > > >> > > Probable issues and fixes
> >> > > > > >> > >
> >> > > > > >> > > 1. We will have to add new APIs to support controller
> >> pushing
> >> > > > tokens
> >> > > > > >> > to
> >> > > > > >> > > brokers on top of the minimal APIs that are currently
> >> > > proposed.
> >> > > > > >> > > 2. We will also have to add APIs to support the
> >> bootstrapping
> >> > > > case,
> >> > > > > >> > i.e,
> >> > > > > >> > > when a new broker comes up it will have to get all
> >> delegation
> >> > > > tokens
> >> > > > > >> > from
> >> > > > > >> > > the controller.
> >> > > > > >> > > 3. In catastrophic failures where all brokers go down,
> >> the
> >> > > > tokens will
> >> > > > > >> > > be lost even if servers are restarted as tokens are not
> >> > > > persisted
> >> > > > > >> > anywhere.
> >> > > > > >> > > If this happens, then there are more important things to
> >> > > worry
> >> > > > about
> >> > > > > >> > and
> >> > > > > >> > > maybe it is better to re-authenticate.
> >> > > > > >> > >
> >> > > > > >> > > (Alternative 2) Do not distribute DT to other brokers at
> >> all.
> >> > > > > >> > >
> >> > > > > >> > > 1. Client authenticates with a broker.
> >> > > > > >> > > 2. Once a client is authenticated, it will make a broker
> >> side
> >> > > > call to
> >> > > > > >> > > issue a delegation token.
> >> > > > > >> > > 3. The broker generates DT of form, [hmac + (owner,
> >> renewer,
> >> > > > > >> > > maxLifeTime, id, hmac, expirationTime)] and passes back
> >> this
> >> > > > DT to
> >> > > > > >> > client.
> >> > > > > >> > > hmac is generated via {HMAC-SHA256(owner, renewer,
> >> > > > maxLifeTime, id,
> >> > > > > >> > hmac,
> >> > > > > >> > > expirationTime) using SecretKey}. Note that all brokers
> >> have
> >> > > > this
> >> > > > > >> > SecretKey.
> >> > > > > >> > > 4. Client then goes to any broker and to authenticate
> >> sends
> >> > > > the DT.
> >> > > > > >> > > Broker recalculates hmac using (owner, renewer,
> >> maxLifeTime,
> >> > > > id, hmac,
> >> > > > > >> > > expirationTime) info from DT and its SecretKey. If it
> >> matches
> >> > > > with
> >> > > > > >> > hmac of
> >> > > > > >> > > DT, client is authenticated. Yes, it will do other
> >> obvious
> >> > > > checks of
> >> > > > > >> > > timestamp expiry and such.
> >> > > > > >> > >
> >> > > > > >> > > Note that secret key will be generated by controller and
> >> passed
> >> > > to
> >> > > > > >> > brokers
> >> > > > > >> > > periodically.
> >> > > > > >> > > Probable issues and fixes
> >> > > > > >> > >
> >> > > > > >> > > 1. How to delete a DT? Yes, that is a downside here.
> >> However,
> >> > > > this can
> >> > > > > >> > > be handled with brokers maintaining a blacklist of DTs,
> >> DTs
> >> > > > from this
> >> > > > > >> > list
> >> > > > > >> > > can be removed after expiry.
> >> > > > > >> > > 2. In catastrophic failures where all brokers go down,
> >> the
> >> > > > tokens will
> >> > > > > >> > > be lost even if servers are restarted as tokens are not
> >> > > > persisted
> >> > > > > >> > anywhere.
> >> > > > > >> > > If this happens, then there are more important things to
> >> > > worry
> >> > > > about
> >> > > > > >> > and
> >> > > > > >> > > maybe it is better to re-authenticate.
> >> > > > > >> > >
> >> > > > > >> > >
> >> > > > > >> > >
> >> > > > > >> > > On Fri, Feb 26, 2016 at 1:58 PM, Parth Brahmbhatt <
> >> > > > > >> > > pbrahmbh...@hortonworks.com> wrote:
> >> > > > > >> > >
> >> > > > > >> > >> Hi,
> >> > > > > >> > >>
> >> > > > > >> > >> I have filed KIP-48 so we can offer hadoop like delegation
> >> > > > tokens in
> >> > > > > >> > >> kafka. You can review the design
> >> > > > > >> > >>
> >> > > > > >> >
> >> > > >
> >> > >
> >> https://cwiki.apache.org/confluence/display/KAFKA/KIP-48+Delegation+token+support+for+Kafka
> >> > > > > >> > .
> >> > > > > >> > >> This KIP depends on KIP-43 and we have also discussed an
> >> > > > alternative to
> >> > > > > >> > >> proposed design here<
> >> > > > > >> > >>
> >> > > > > >> >
> >> > > >
> >> > >
> >> https://issues.apache.org/jira/browse/KAFKA-1696?focusedCommentId=15167800&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15167800
> >> > > > > >> > >> >.
> >> > > > > >> > >>
> >> > > > > >> > >> Thanks
> >> > > > > >> > >> Parth
> >> > > > > >> > >>
> >> > > > > >> > >
> >> > > > > >> > >
> >> > > > > >> > >
> >> > > > > >> > > --
> >> > > > > >> > >
> >> > > > > >> > > Regards,
> >> > > > > >> > > Ashish
> >> > > > > >> >
> >> > > >
> >> > >
> >> > >
> >> > >
> >> > > --
> >> > >
> >> > > Regards,
> >> > > Ashish
> >> > >
> >>
