Hi Ryanne, Thanks for the KIP and patient discussion. +1 from me as well.
Jiangjie (Becket) Qin On Fri, Jan 11, 2019 at 1:11 AM Jun Rao <j...@confluent.io> wrote: > Hi, Ryanne, > > Thanks for the explanation. All make sense to me now. +1 on the KIP from > me. > > Jun > > On Wed, Jan 9, 2019 at 7:16 PM Ryanne Dolan <ryannedo...@gmail.com> wrote: > > > Thanks Jun. > > > > > 103. My point was that the MirrorMakerConnector can die while the > > Heartbeat connector is still alive. So, one can't solely rely on > Heartbeat > > for monitoring? > > > > Each cluster will have a heartbeat topic produced by > > MirrorHeartbeatConnector, which doesn't have an associated "source" other > > than time. This topic gets picked up by downstream MirrorSourceConnectors > > and replicated like A.heartbeat. So the heartbeat topic itself isn't > > particular useful for monitoring, but the downstream A.heartbeat shows > that > > heartbeats are being replicated successfully from A -> B. If a > > MirrorSourceConnector fails while replicating A -> B, you'd still see > > heartbeats in cluster B, but not A.heartbeat. > > > > 105. You're correct, you don't need to know "B" in order to go from A's > > topic1 to B's A.topic1, i.e. migrating downstream. But you need to know > "B" > > to go from A's B.topic1 to B's topic1. In the latter case, you are > > consuming a remote topic to begin with, and then migrating to the source > > cluster, i.e. migrating upstream. N.B. you strip the "B" prefix in this > > case, rather than add the "A" prefix. And you can't just strip all > > prefixes, because you could be migrating from e.g. A's C.topic1 to B's > > C.topic1, i.e. migrating "laterally", if you will. > > > > I suppose we could break this out into multiple methods (upstream, > > downstream, lateral etc), but I think that would add a lot more > complexity > > and confusion to the API. By providing both A and B, the single method > can > > always figure out what to do. > > > > 107. done > > > > Thanks, > > Ryanne > > > > > > > > > > On Wed, Jan 9, 2019 at 6:11 PM Jun Rao <j...@confluent.io> wrote: > > > >> Hi, Ryanne, > >> > >> 103. My point was that the MirrorMakerConnector can die while the > >> Heartbeat connector is still alive. So, one can't solely rely on > Heartbeat > >> for monitoring? > >> > >> 105. Hmm, maybe I don't understand how this is done. Let's say we > replica > >> topic1 from cluster A to cluster B. My understanding is that to > translate > >> the offset from A to B for a consumer group, we read A.checkpoint file > in > >> cluster B to get the timestamp of the last checkpointed offset, call > >> consumer.offsetsForTimes() on A.topic1 in cluster B to translate the > >> timestamp to a local offset, and return <A.topic1, translated offset>. > >> Is that right? If so, in all steps, we don't need to know the > >> targetClusterAlias B. We just need to know the connection string to > >> cluster B, which targetConsumerConfig provides. > >> > >> 107. Thanks. Could you add that description to the KIP? > >> > >> Thanks, > >> > >> Jun > >> > >> On Mon, Jan 7, 2019 at 3:50 PM Ryanne Dolan <ryannedo...@gmail.com> > >> wrote: > >> > >>> Thanks Jun, I've updated the KIP as requested. Brief notes below: > >>> > >>> 100. added "...out-of-the-box (without custom handlers)..." > >>> > >>> 101. done. Good idea to include a MessageFormatter. > >>> > >>> 102. done. > >>> > >>> > 103. [...] why is Heartbeat a separate connector? > >>> > >>> Heartbeats themselves are replicated via MirrorSource/SinkConnector, so > >>> if replication stops, you'll stop seeing heartbeats in downstream > clusters. > >>> I've updated the KIP to make this clearer and have added a bullet to > >>> Rejected Alternatives. > >>> > >>> 104. added "heartbeat.retention.ms", "checkpoint.retention.ms", > thanks. > >>> The heartbeat topic doesn't need to be compacted. > >>> > >>> > 105. [...] I am not sure why targetClusterAlias is useful > >>> > >>> In order to map A's B.topic1 to B's topic1, we need to know B. > >>> > >>> > 106. [...] should the following properties be prefixed with > "consumer." > >>> > >>> No, they are part of Connect's worker config. > >>> > >>> > 107. So, essentially it's running multiple logical connect clusters > on > >>> the same shared worker nodes? > >>> > >>> Correct. Rather than configure each Connector and Worker and Herder > >>> individually, a single top-level configuration file is used. And > instead of > >>> running a bunch of separate worker processes on each node, a single > process > >>> runs multiple workers. This is implemented using a separate driver > based on > >>> ConnectDistributed, but which runs multiple DistributedHerders. Each > >>> DistributedHerder uses a different Kafka cluster for coordination -- > they > >>> are completely separate apart from running in the same process. > >>> > >>> Thanks for helping improve the doc! > >>> Ryanne > >>> > >>> On Fri, Jan 4, 2019 at 10:33 AM Jun Rao <j...@confluent.io> wrote: > >>> > >>>> Hi, Ryanne, > >>>> > >>>> Thanks for KIP. Still have a few more comments below. > >>>> > >>>> 100. "This is not possible with MirrorMaker today -- records would be > >>>> replicated back and forth indefinitely, and the topics in either > cluster > >>>> would be merged inconsistently between clusters. " This is not 100% > true > >>>> since MM can do the topic renaming through MirrorMakerMessageHandler. > >>>> > >>>> 101. For both Heartbeat and checkpoint, could you define the full > >>>> schema, > >>>> including the field type? Also how are they serialized into the Kafka > >>>> topic? Is it JSON or sth else? For convenience, it would be useful to > >>>> provide a built-in MessageFormatter so that one can read each topic's > >>>> data > >>>> using tools like ConsoleConsumer. > >>>> > >>>> 102. For the public Heartbeat and Checkpoint class, could you list the > >>>> public methods in each class? > >>>> > >>>> 103. I am wondering why is Heartbeat a separate connector? A > MirrorMaker > >>>> connector can die independent of the Heartbeat connector, which seems > to > >>>> defeat the purpose of heartbeat. > >>>> > >>>> 104. Is the Heartbeat topic also a compacted topic? If not, how long > is > >>>> it > >>>> retained for? > >>>> > >>>> 105. For the following, I am not sure why targetClusterAlias is > useful? > >>>> The > >>>> checkpoint file seems to only include sourceClusterAlias. > >>>> > >>>> Map<TopicPartition, Long> translateOffsets(Map<?, ?> > >>>> targetConsumerConfig, > >>>> String sourceClusterAlias, String targetClusterAlias, String > >>>> remoteGroupId) > >>>> > >>>> 106. In the configuration example, should the following properties be > >>>> prefixed with "consumer."? > >>>> key.converter > >>>> <https://cwiki.apache.org/confluence/display/KAFKA/key.converter> = > >>>> org.apache.kafka.connect.converters.ByteArrayConverter > >>>> < > >>>> > https://cwiki.apache.org/confluence/display/KAFKA/org.apache.kafka.connect.converters.ByteArrayConverter > >>>> > > >>>> value.converter > >>>> <https://cwiki.apache.org/confluence/display/KAFKA/value.converter> = > >>>> org.apache.kafka.connect.converters.ByteArrayConverter > >>>> < > >>>> > https://cwiki.apache.org/confluence/display/KAFKA/org.apache.kafka.connect.converters.ByteArrayConverter > >>>> > > >>>> > >>>> 107. Could you add a bit more description on how > >>>> connect-mirror-maker.sh is > >>>> implemented? My understanding is that it will start as many as > >>>> separate DistributedHerder as the Kafka clusters? So, essentially it's > >>>> running multiple logical connect clusters on the same shared worker > >>>> nodes? > >>>> > >>>> Thanks, > >>>> > >>>> Jun > >>>> > >>>> > >>>> On Thu, Dec 20, 2018 at 5:23 PM Srinivas Reddy < > >>>> srinivas96all...@gmail.com> > >>>> wrote: > >>>> > >>>> > +1 (non binding) > >>>> > > >>>> > Thank you Ryan for the KIP, let me know if you need support in > >>>> implementing > >>>> > it. > >>>> > > >>>> > - > >>>> > Srinivas > >>>> > > >>>> > - Typed on tiny keys. pls ignore typos.{mobile app} > >>>> > > >>>> > > >>>> > On Fri, 21 Dec, 2018, 08:26 Ryanne Dolan <ryannedo...@gmail.com > >>>> wrote: > >>>> > > >>>> > > Thanks for the votes so far! > >>>> > > > >>>> > > Due to recent discussions, I've removed the high-level REST API > >>>> from the > >>>> > > KIP. > >>>> > > > >>>> > > On Thu, Dec 20, 2018 at 12:42 PM Paul Davidson < > >>>> pdavid...@salesforce.com > >>>> > > > >>>> > > wrote: > >>>> > > > >>>> > > > +1 > >>>> > > > > >>>> > > > Would be great to see the community build on the basic approach > >>>> we took > >>>> > > > with Mirus. Thanks Ryanne. > >>>> > > > > >>>> > > > On Thu, Dec 20, 2018 at 9:01 AM Andrew Psaltis < > >>>> > psaltis.and...@gmail.com > >>>> > > > > >>>> > > > wrote: > >>>> > > > > >>>> > > > > +1 > >>>> > > > > > >>>> > > > > Really looking forward to this and to helping in any way I > can. > >>>> > Thanks > >>>> > > > for > >>>> > > > > kicking this off Ryanne. > >>>> > > > > > >>>> > > > > On Thu, Dec 20, 2018 at 10:18 PM Andrew Otto < > >>>> o...@wikimedia.org> > >>>> > > wrote: > >>>> > > > > > >>>> > > > > > +1 > >>>> > > > > > > >>>> > > > > > This looks like a huge project! Wikimedia would be very > >>>> excited to > >>>> > > have > >>>> > > > > > this. Thanks! > >>>> > > > > > > >>>> > > > > > On Thu, Dec 20, 2018 at 9:52 AM Ryanne Dolan < > >>>> > ryannedo...@gmail.com> > >>>> > > > > > wrote: > >>>> > > > > > > >>>> > > > > > > Hey y'all, please vote to adopt KIP-382 by replying +1 to > >>>> this > >>>> > > > thread. > >>>> > > > > > > > >>>> > > > > > > For your reference, here are the highlights of the > proposal: > >>>> > > > > > > > >>>> > > > > > > - Leverages the Kafka Connect framework and ecosystem. > >>>> > > > > > > - Includes both source and sink connectors. > >>>> > > > > > > - Includes a high-level driver that manages connectors in > a > >>>> > > dedicated > >>>> > > > > > > cluster. > >>>> > > > > > > - High-level REST API abstracts over connectors between > >>>> multiple > >>>> > > > Kafka > >>>> > > > > > > clusters. > >>>> > > > > > > - Detects new topics, partitions. > >>>> > > > > > > - Automatically syncs topic configuration between > clusters. > >>>> > > > > > > - Manages downstream topic ACL. > >>>> > > > > > > - Supports "active/active" cluster pairs, as well as any > >>>> number > >>>> > of > >>>> > > > > active > >>>> > > > > > > clusters. > >>>> > > > > > > - Supports cross-data center replication, aggregation, and > >>>> other > >>>> > > > > complex > >>>> > > > > > > topologies. > >>>> > > > > > > - Provides new metrics including end-to-end replication > >>>> latency > >>>> > > > across > >>>> > > > > > > multiple data centers/clusters. > >>>> > > > > > > - Emits offsets required to migrate consumers between > >>>> clusters. > >>>> > > > > > > - Tooling for offset translation. > >>>> > > > > > > - MirrorMaker-compatible legacy mode. > >>>> > > > > > > > >>>> > > > > > > Thanks, and happy holidays! > >>>> > > > > > > Ryanne > >>>> > > > > > > > >>>> > > > > > > >>>> > > > > > >>>> > > > > >>>> > > > > >>>> > > > -- > >>>> > > > Paul Davidson > >>>> > > > Principal Engineer, Ajna Team > >>>> > > > Big Data & Monitoring > >>>> > > > > >>>> > > > >>>> > > >>>> > >>> >
