Hi Yogesh, A few questions:
1. Please share the code for the test script. 2. At which point in the sequence below was the code for the brokers updated to 0.10.2? 3. When doing a rolling restart, it's generally a good idea to ensure that there are no under-replicated partitions. 4. Is controlled shutdown completing successfully? Ismael On Tue, Sep 19, 2017 at 12:33 PM, Yogesh Sangvikar < yogesh.sangvi...@gmail.com> wrote: > Hi Team, > > Thanks for providing comments. > > Here adding more details on steps followed for upgrade, > > Cluster details: We are using 4 node kafka cluster and topics with 3 > replication factor. For upgrade test, we are using a topic with 5 > partitions & 3 replication factor. > > Topic:student-activity PartitionCount:5 ReplicationFactor:3 > Configs: > Topic: student-activity Partition: 0 Leader: 4 Replicas: > 4,2,3 Isr: 4,2,3 > Topic: student-activity Partition: 1 Leader: 1 Replicas: > 1,3,4 Isr: 1,4,3 > Topic: student-activity Partition: 2 Leader: 2 Replicas: > 2,4,1 Isr: 2,4,1 > Topic: student-activity Partition: 3 Leader: 3 Replicas: > 3,1,2 Isr: 1,2,3 > Topic: student-activity Partition: 4 Leader: 4 Replicas: > 4,3,1 Isr: 4,1,3 > > We are using a test script to publish events continuously to one of the > topic partition (here partition 3) and monitoring the scripts total > published events count with the partition 3 offset value. > > [ Note: The topic partitions offset count may differ from CLI utility and > screenshot due to capture delay. ] > > - First, we have rolling restarted all kafka brokers for explicit > protocol and message version to 0.10.0, > inter.broker.protocol.version=0.10.0 > > log.message.format.version=0.10.0 > > - During this restarted, the events are getting published as expected > and counters are increasing & in-sync replicas are coming up immediately > post restart. > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > student-activity:3:785 > student-activity:0:1 > [image: Inline image 1] > > > - Next, we have rolling restarted kafka brokers for > "inter.broker.protocol.version=0.10.2" in below broker sequence. (note > that, test script is publishing events to the topic partition continuously) > > - Restarted server with broker.id = 4, > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > student-activity:3:1189 > student-activity:0:1 > > [image: Inline image 2] > > - Restarted server with broker.id = 3, > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > *student-activity:3:1430* > student-activity:0:1 > > > [image: Inline image 3] > > > - Restarted server with broker.id = 2, (here, observe the partition 3 > offset count is decreased from last restart offset) > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > *student-activity:3:1357* > student-activity:0:1 > > [image: Inline image 4] > > > - Restarted last server with broker.id = 1, > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > student-activity:3:1613 > student-activity:0:1 > [image: Inline image 5] > > - Finally, rolling restarted all brokers (in same sequence above) for > "log.message.format.version=0.10.2" > > > [image: Inline image 6] > [image: Inline image 7] > [image: Inline image 8] > > [image: Inline image 9] > > - The topic offset counter after final restart, > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > student-activity:3:2694 > student-activity:0:1 > > > - And, the topic offset counter after stopping events publish script, > > [***@***.***.***.*** confluent-3.2.2]$ ./bin/kafka-run-class > kafka.tools.GetOffsetShell --broker-list ***.***.***.***:9092,***.***.* > **.***:9092,***.***.***.***:9092,***.***.***.***:9092 --topic > student-activity --time -1 > student-activity:2:1 > student-activity:4:1 > student-activity:1:68 > student-activity:3:2769 > student-activity:0:1 > > - Calculating missing events counts, > Total events published by script to partition 3 : > *3090 *Offset count on Partition 3 : > *2769 * > Missing events count : 3090 - 2769 = *321* > > > As per above observation during rolling restart for protocol version, > > 1. The partition 3 leader changed to in-sync replica 2 (with older > protocol version) and upgraded replicas (3 & 4) are missing from in-sync > replica list. > 2. And, one we down server 2 down for upgrade, suddenly replicas 3 & 4 > appear in in-sync replica list and partition offset count resets. > 3. Post server 2 & 1 upgrade, 3 in-sync replicas shown for partition 3 > but, missing events lag is not recovered. > > Please let us know your comments on our observations and correct us if we > are missing any upgrade steps. > > Thanks, > Yogesh > > On Tue, Sep 19, 2017 at 2:07 AM, Ismael Juma <ism...@juma.me.uk> wrote: > >> Hi Scott, >> >> There is nothing preventing a replica running a newer version from being >> in >> sync as long as the instructions are followed (i.e. >> inter.broker.protocol.version has to be set correctly and, if there's a >> message format change, log.message.format.version). That's why I asked >> Yogesh for more details. The upgrade path he mentioned (0.10.0 -> 0.10.2) >> is straightforward, there isn't a message format change, so only >> inter.broker.protocol.version needs to be set. >> >> Ismael >> >> On Mon, Sep 18, 2017 at 5:50 PM, Scott Reynolds < >> sreyno...@twilio.com.invalid> wrote: >> >> > Can we get some clarity on this point: >> > >older version leader is not allowing newer version replicas to be in >> sync, >> > so the data pushed using this older version leader >> > >> > That is super scary. >> > >> > What protocol version is the older version leader running? >> > >> > Would this happen if you are skipping a protocol version bump? >> > >> > >> > >> > On Mon, Sep 18, 2017 at 9:33 AM Ismael Juma <ism...@juma.me.uk> wrote: >> > >> > > Hi Yogesh, >> > > >> > > Can you please clarify what you mean by "observing data loss"? >> > > >> > > Ismael >> > > >> > > On Mon, Sep 18, 2017 at 5:08 PM, Yogesh Sangvikar < >> > > yogesh.sangvi...@gmail.com> wrote: >> > > >> > > > Hi Team, >> > > > >> > > > Please help to find resolution for below kafka rolling upgrade >> issue. >> > > > >> > > > Thanks, >> > > > >> > > > Yogesh >> > > > >> > > > On Monday, September 18, 2017 at 9:03:04 PM UTC+5:30, Yogesh >> Sangvikar >> > > > wrote: >> > > >> >> > > >> Hi Team, >> > > >> >> > > >> Currently, we are using confluent 3.0.0 kafka cluster in our >> > production >> > > >> environment. And, we are planing to upgrade the kafka cluster for >> > > confluent >> > > >> 3.2.2 >> > > >> We are having topics with millions on records and data getting >> > > >> continuously published to those topics. And, also, we are using >> other >> > > >> confluent services like schema-registry, kafka connect and kafka >> rest >> > to >> > > >> process the data. >> > > >> >> > > >> So, we can't afford downtime upgrade for the platform. >> > > >> >> > > >> We have tries rolling kafka upgrade as suggested on blogs in >> > Development >> > > >> environment, >> > > >> >> > > >> >> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__docs. >> > confluent.io_3.2.2_upgrade.html&d=DwIBaQ&c=x_Y1Lz9GyeGp2OvBCa_eow&r= >> > ChXZJWKniTslJvQGptpIW7qAh4kkrpgYSer_wfh4G5w&m=JGTnLlVIAvVddNas19L_ >> > w54zWrVd48xst46GuPGCxV0&s=DMcA8JOnGXNNa_dRFpkNOd7AJoIQUgkEcw >> 6q06RHgl0&e= >> > > >> >> > > >> >> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__kafka. >> > apache.org_documentation_-23upgrade&d=DwIBaQ&c=x_Y1Lz9GyeGp2 >> OvBCa_eow&r= >> > ChXZJWKniTslJvQGptpIW7qAh4kkrpgYSer_wfh4G5w&m=JGTnLlVIAvVddNas19L_ >> > w54zWrVd48xst46GuPGCxV0&s=0p4Fn8sKMbVJMR6nk42C-lhyujAEVUXTYZ >> JhteC11Fs&e= >> > > >> >> > > >> But, we are observing data loss on topics while doing rolling >> upgrade >> > / >> > > >> restart of kafka servers for "inter.broker.protocol.version >> =0.10.2". >> > > >> >> > > >> As per our observation, we suspect the root cause for the data loss >> > > >> (explained for a topic partition having 3 replicas), >> > > >> >> > > >> - As the kafka broker protocol version updates from 0.10.0 to >> > 0.10.2 >> > > >> in rolling fashion, the in-sync replicas having older version >> will >> > > not >> > > >> allow updated replicas (0.10.2) to be in sync unless are all >> > updated. >> > > >> - Also, we have explicitly disabled "unclean.leader.election. >> > enabled" >> > > >> property, so only in-sync replicas will be elected as leader for >> > the >> > > given >> > > >> partition. >> > > >> - While doing rolling fashion update, as mentioned above, older >> > > >> version leader is not allowing newer version replicas to be in >> > sync, >> > > so the >> > > >> data pushed using this older version leader, will not be synced >> > with >> > > other >> > > >> replicas and if this leader(older version) goes down for an >> > > upgrade, other >> > > >> updated replicas will be shown in in-sync column and become >> leader, >> > > but >> > > >> they lag in offset with old version leader and shows the offset >> of >> > > the data >> > > >> till they have synced. >> > > >> - And, once the last replica comes up with updated version, will >> > > >> start syncing data from the current leader. >> > > >> >> > > >> >> > > >> Please let us know comments on our observation and suggest proper >> way >> > > for >> > > >> rolling kafka upgrade as we can't afford downtime. >> > > >> >> > > >> Thanks, >> > > >> Yogesh >> > > >> >> > > > >> > > >> > -- >> > >> > Scott Reynolds >> > Principal Engineer >> > [image: twilio] <http://www.twilio.com/?utm_source=email_signature> >> > MOBILE (630) 254-2474 >> > EMAIL sreyno...@twilio.com >> > >> > >
