kafka/raft
Alyssa Huang 3170e1130c
CI / build (push) Has been cancelled Details
KAFKA-18345; Prevent livelocked elections (#19658)
At the retry limit binaryExponentialElectionBackoffMs it becomes
statistically likely that the exponential backoff returned
electionBackoffMaxMs. This is an issue as multiple replicas can get
stuck starting elections at the same cadence.

This change fixes that by added a random jitter to the max election
backoff.

Reviewers: José Armando García Sancio <jsancio@apache.org>, TaiJuWu
 <tjwu1217@gmail.com>, Yung <yungyung7654321@gmail.com>
2025-05-20 16:10:23 -04:00
..
bin KAFKA-18388 test-kraft-server-start.sh should use log4j2.yaml (#18370) 2025-01-07 04:20:29 +08:00
config KAFKA-18388 test-kraft-server-start.sh should use log4j2.yaml (#18370) 2025-01-07 04:20:29 +08:00
src KAFKA-18345; Prevent livelocked elections (#19658) 2025-05-20 16:10:23 -04:00
.gitignore KAFKA-13429: ignore bin on new modules (#11415) 2021-11-10 14:36:24 -06:00
README.md KAFKA-17728 Add missing config `replica-directory-id` to raft README (#17518) 2024-10-17 11:32:27 +08:00

README.md

KRaft (Kafka Raft)

KRaft (Kafka Raft) is a protocol based on the Raft Consensus Protocol tailored for Apache Kafka.

This is used by Apache Kafka in the KRaft (Kafka Raft Metadata) mode. We also have a standalone test server which can be used for performance testing. We describe the details to set this up below.

Run Single Quorum

bin/test-kraft-server-start.sh --config config/kraft.properties --replica-directory-id b8tRS7h4TJ2Vt43Dp85v2A

Run Multi Node Quorum

Create 3 separate KRaft quorum properties as the following:

cat << EOF >> config/kraft-quorum-1.properties

node.id=1
listeners=PLAINTEXT://localhost:9092
controller.listener.names=PLAINTEXT
controller.quorum.voters=1@localhost:9092,2@localhost:9093,3@localhost:9094
log.dirs=/tmp/kraft-logs-1
EOF

cat << EOF >> config/kraft-quorum-2.properties

node.id=2
listeners=PLAINTEXT://localhost:9093
controller.listener.names=PLAINTEXT
controller.quorum.voters=1@localhost:9092,2@localhost:9093,3@localhost:9094
log.dirs=/tmp/kraft-logs-2
EOF

cat << EOF >> config/kraft-quorum-3.properties

node.id=3
listeners=PLAINTEXT://localhost:9094
controller.listener.names=PLAINTEXT
controller.quorum.voters=1@localhost:9092,2@localhost:9093,3@localhost:9094
log.dirs=/tmp/kraft-logs-3
EOF

Open up 3 separate terminals, and run individual commands:

bin/test-kraft-server-start.sh --config config/kraft-quorum-1.properties --replica-directory-id b8tRS7h4TJ2Vt43Dp85v2A
bin/test-kraft-server-start.sh --config config/kraft-quorum-2.properties --replica-directory-id Nkij_D9XRiYKNb41SiJo7Q
bin/test-kraft-server-start.sh --config config/kraft-quorum-3.properties --replica-directory-id 4-e97nI7eHPYKfEDtW8rtQ

Once a leader is elected, it will begin writing to an internal __raft_performance_test topic with a steady workload of random data. You can control the workload using the --throughput and --record-size arguments passed to test-kraft-server-start.sh.