Amazon Managed Streaming for Apache Kafka
Developer Guide

The Default Amazon MSK Configuration

When you create an MSK cluster without specifying a custom MSK configuration, Amazon MSK creates and uses a default configuration with the values shown in the following table. For properties that aren't in this table, Amazon MSK uses the defaults associated with your version of Apache Kafka. For a list of these default values, see Apache Kafka Configuration.

Default Configuration Values

Name Description Default Value
allow.everyone.if.no.acl.found If no resource patterns match a specific resource, the resource has no associated ACLs. In this case, if this property is set to true, everyone is allowed to access the resource, not just the super users. true
auto.create.topics.enable Enables autocreation of a topic on the server. false
auto.leader.rebalance.enable Enables auto leader balancing. A background thread checks and triggers leader balance if required at regular intervals. true
default.replication.factor Default replication factors for automatically created topics. 3
min.insync.replicas

When a producer sets acks to "all" (or "-1"), min.insync.replicas specifies the minimum number of replicas that must acknowledge a write for the write to be considered successful. If this minimum can't be met, the producer raises an exception (either NotEnoughReplicas or NotEnoughReplicasAfterAppend).

When used together, min.insync.replicas and acks enable you to enforce greater durability guarantees. A typical scenario would be to create a topic with a replication factor of 3, set min.insync.replicas to 2, and produce with acks of "all". This ensures that the producer raises an exception if a majority of replicas do not receive a write.

2
num.io.threads Number of threads that the server uses for processing requests, which may include disk I/O. 8
num.network.threads Number of threads that the server uses for receiving requests from the network and sending responses to the network. 5
num.partitions Default number of log partitions per topic. 1
num.replica.fetchers Number of fetcher threads used to replicate messages from a source broker. Increasing this value can increase the degree of I/O parallelism in the follower broker. 2
socket.receive.buffer.bytes SO_RCVBUF buffer of the socket sever sockets. If the value is -1, the OS default is used. 102400
socket.request.max.bytes Maximum number of bytes in a socket request. 104857600
socket.send.buffer.bytes SO_SNDBUF buffer of the socket sever sockets. If the value is -1, the OS default is used. 102400
unclean.leader.election.enable Indicates whether to enable replicas not in the ISR set to be elected as leader as a last resort, even though doing so may result in data loss. true
zookeeper.set.acl Set client to use secure ACLs. false