diff --git a/docs/ops.html b/docs/ops.html index ffaca8bf3b863..3177b49d48722 100644 --- a/docs/ops.html +++ b/docs/ops.html @@ -4281,6 +4281,32 @@
Starting from Apache Kafka 4.0, Eligible Leader Replicas (KIP-966 Part 1)
+ is available for the users to an improvement to Kafka replication. As the "strict min ISR" rule has been generally applied, which means the high watermark for the data partition can't advance
+ if the size of the ISR is smaller than the min ISR(min.insync.replicas
), it makes some replicas that are not in the ISR safe to become the leader. The KRaft controller
+ stores such replicas in the PartitionRecord field called Eligible Leader Replicas
. During the leader election, the controller will select the leaders
+ with the following order:
The ELR is not enabled by default for 4.0. To enable the new protocol on the server, set eligible.leader.replicas.version=1
. After that the upgrade, the KRaft
+ controller will start tracking the ELR.
Downgrades are safe to perform by setting eligible.leader.replicas.version=0
.
The ELR fields can be checked through the API DescribeTopicPartitions. The admin client can fetch the ELR info by describing the topics.
+ Also note that, if min.insync.replicas
is updated for a topic, the ELR field will be cleaned. If cluster default min ISR is updated,
+ all the ELR fields will be cleaned.
Eligible Leader Replicas
(ELR).
+ For more information check here
+