Page History

...

package org.apache.kafka.server.group.consumer;

public interface PartitionAssignor {

    class AssignmentSpec {
        /**
         * The members keyed by member id.
         */
        Map<String, AssignmentMemberSpec> members;

        /**
         * The topics' metadata keyed by topic id
         */
        Map<Uuid, AssignmentTopicMetadata> topics;
    }

    class AssignmentMemberSpec {
        /**
         * The instance ID if provided.
         */
        Optional<String> instanceId;

        /**
         * The rack ID if provided.
         */
        Optional<String> rackId;

        /**
         * The topics that the member is subscribed to.
         */
        Collection<String> subscribedTopics;

        /**
         * The current target partitions of the member.
         */
        Collection<TopicPartition> targetPartitions;
    }

    class AssignmentTopicMetadata {
        /**
         * The topic name.
         */
        String topicName;

        /**
		 * The number of partitions.
		 */
		int numPartitions; 
    }

    class GroupAssignment {
        /**
         * The member assignments keyed by member id.
         */
        Map<String, MemberAssignment> members;
    }

    class MemberAssignment {
        /**
         * The target partitions assigned to this member.
         */
        Collection<TopicPartition> targetPartitions;
    }

    /**
     * Unique name for this assignor.
     */
    String name();

    /**
     * Perform the group assignment given the current members and
     * topic metadata.
     *
     * @param assignmentSpec The assignment spec.
     * @return The new assignment for the group.
     */
    GroupAssignment assign(AssignmentSpec assignmentSpec) throws PartitionAssignorException;
}

Broker Metrics

The set of new metrics is not clear at the moment. We plan to amend the KIP later on when progress on the implementation would have been made.

Group Coordinator Runtime Metrics

kafka.server:type=group-coordinator-metrics,name=num-partitions,state=loading

• number of __consumer_offsets partitions in Loading state

kafka.server:type=group-coordinator-metrics,name=num-partitions,state=active

• number of __consumer_offsets partitions in Active state

kafka.server:type=group-coordinator-metrics,name=num-partitions,state=failed

• number of __consumer_offsets partitions in Failed state

kafka.server:type=group-coordinator-metrics,name=event-queue-size

• event accumulator queue size

partition load sensor: partition load time

• kafka.server:type=group-coordinator-metrics,name=partition-load-time-max
• kafka.server:type=group-coordinator-metrics,name=partition-load-time-avg

thread idle ratio sensor: thread busy - idle ratio

• kafka.server:type=group-coordinator-metrics,name=thread-idle-ratio-min
• kafka.server:type=group-coordinator-metrics,name=thread-idle-ratio-avg

Group Coordinator Metrics

Existing generic group metrics have been migrated, with the same metric names.

kafka.server:type=group-coordinator-metrics,name=consumer-groups-count

• number of consumer groups

kafka.server:type=group-coordinator-metrics,name=consumer-groups-count,state=empty

• number of consumer groups in Empty state

kafka.server:type=group-coordinator-metrics,name=consumer-groups-count,state=assigning

• number of consumer groups in Assigning state

kafka.server:type=group-coordinator-metrics,name=consumer-groups-count,state=reconciling

• number of consumer groups in Reconciling state

kafka.server:type=group-coordinator-metrics,name=consumer-groups-count,state=stable

• number of consumer groups in Stable state

kafka.server:type=group-coordinator-metrics,name=consumer-groups-count,state=dead

• number of consumer groups in Dead state

generic group preparing rebalance sensor

• kafka.server:type=group-coordinator-metrics,name=generic-group-rebalance-rate
• kafka.server:type=group-coordinator-metrics,name=generic-group-rebalance-count

consumer group rebalances sensor

• kafka.server:type=group-coordinator-metrics,name=consumer-group-rebalance-rate
• kafka.server:type=group-coordinator-metrics,name=consumer-group-rebalance-count
• Group count by type
• Group count by state
• Rebalance Rate
• Thread utilisation in percent

Broker Configurations

New properties in the broker configuration.

...