Hey Ismael, my understanding is that we are inevitably making the controller single point, even when the metadata quorum work is done. Redirecting won't make things easier as the controller will still be the role to perform alterations.
Just for the sake of argument, DescribeTopic is not migrated as it is read access. Even I don't have concrete numbers to justify any production use case for Kafka, mostly people do metadata lookup more frequent than mutation if you agree. Also I don't fully understand why the load of AlterISR is necessary better than admin requests, which could also be harming the cluster availability when there are growing URPs? The performance is definitely a good concern for all these single-point access changes, we would definitely build benchmarks in KIP-500 scope to understand any potential regression, which may go beyond the scope of the current KIP and build a separate interesting topic to discuss. Boyang On Thu, Apr 16, 2020 at 8:52 AM Ismael Juma <ism...@juma.me.uk> wrote: > I don't think these requests are necessarily infrequent under multi tenant > environments though. I've seen Controller availability being an issue for > describe topics for example (before it was changed to go to any broker). > > Would it be better to redirect once the controller quorum is there? > > Note that this is different from things like AlterIsr since these calls are > coming from clients versus other brokers. > > Ismael > > On Wed, Apr 15, 2020, 5:10 PM Colin McCabe <cmcc...@apache.org> wrote: > > > Hi Ismael, > > > > I agree that sending these requests through the controller will not work > > during the periods when there is no controller. However, those periods > > should be short-- otherwise we have bigger problems in the cluster. > > > > These requests are very infrequent because they are administrative > > operations. Basically the affected operations are changing ACLs, > changing > > dynamic configurations, and changing quotas. > > > > best, > > Colin > > > > > > On Wed, Apr 15, 2020, at 15:25, Ismael Juma wrote: > > > Hi Boyang, > > > > > > Thanks for the KIP. Have we considered that this reduces availability > for > > > these operations since we have a single Controller instead of the ZK > > quorum? > > > > > > Ismael > > > > > > On Fri, Apr 3, 2020 at 4:45 PM Boyang Chen <reluctanthero...@gmail.com > > > > > wrote: > > > > > > > Hey all, > > > > > > > > I would like to start off the discussion for KIP-590, a follow-up > > > > initiative after KIP-500: > > > > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-590%3A+Redirect+Zookeeper+Mutation+Protocols+to+The+Controller > > > > > > > > This KIP proposes to migrate existing Zookeeper mutation paths, > > including > > > > configuration, security and quota changes, to controller-only by > always > > > > routing these alterations to the controller. > > > > > > > > Let me know your thoughts! > > > > > > > > Best, > > > > Boyang > > > > > > > > > >
