Apache Kafka 入门 - Kafka命令详细介绍
Apache Kafka 入门
Apache Kafka 入门大概分为5篇博客，内容都比较基础，计划包含以下内容：
- Kafka的基本配置和运行
- Kafka命令详细介绍
- Kafka-manager的基本配置和运行
- Kafka API 简单用法
- Spring Boot 集成Kafka
Kafka支持Linux和WIndows环境，本文运行环境使用Linux（CentOS）。
本篇为第二篇。
Kafka命令行详细介绍
常用的几个命令如下：
- kafka-server-start.sh
- kafka-console-consumer.sh
- kafka-console-producer.sh
- kafka-topics.sh
在这几个命令中，第一个仅用于启动Kafka，后两个console常用于测试，用途最多的是最后一个命令，所以下面命令中主要介绍的就是 kafka-topics.sh。
kafka-server-start.sh
用法：> bin/kafka-server-start.sh [-daemon] server.properties [--override property=value]*
这个命令后面可以有多个参数，第一个是可选参数，该参数可以让当前命令以后台服务方式执行，第二个必须是 Kafka 的配置文件。后面还可以有多个--override开头的参数，其中的property可以是Broker Configs中提供的所有参数。这些额外的参数会覆盖配置文件中的设置。
例如下面使用同一个配置文件，通过参数覆盖启动多个Broker。
> bin/kafka-server-start.sh -daemon config/server.properties --override broker.id=0 --override log.dirs=/tmp/kafka-logs-1 --override listeners=PLAINTEXT://:9092 --override advertised.listeners=PLAINTEXT://192.168.16.150:9092
> bin/kafka-server-start.sh -daemon config/server.properties --override broker.id=1 --override log.dirs=/tmp/kafka-logs-2 --override listeners=PLAINTEXT://:9093 --override advertised.listeners=PLAINTEXT://192.168.16.150:9093上面这种用法只是用于演示，真正要启动多个Broker 应该针对不同的 Broker 创建相应的 server.properties 配置。
kafka-console-consumer.sh
这个命令只是简单的将消息输出到标准输出中，该命令支持的参数如下。
option Description
------ -----------
--blacklist <String: blacklist> Blacklist of topics to exclude from
consumption.
--bootstrap-server <String: server to REQUIRED (unless old consumer is
connect to> used): The server to connect to.
--consumer-property <String: A mechanism to pass user-defined
consumer_prop> properties in the form key=value to
the consumer.
--consumer.config <String: config file> Consumer config properties file. Note
that [consumer-property] takes
precedence over this config.
--csv-reporter-enabled If set, the CSV metrics reporter will
be enabled
--delete-consumer-offsets If specified, the consumer path in
zookeeper is deleted when starting up
--enable-systest-events Log lifecycle events of the consumer
in addition to logging consumed
messages. (This is specific for
system tests.)
--formatter <String: class> The name of a class to use for
formatting kafka messages for
display. (default: kafka.tools.
DefaultMessageFormatter)
--from-beginning If the consumer does not already have
an established offset to consume
from, start with the earliest
message present in the log rather
than the latest message.
--key-deserializer <String:
deserializer for key>
--max-messages <Integer: num_messages> The maximum number of messages to
consume before exiting. If not set,
consumption is continual.
--metrics-dir <String: metrics If csv-reporter-enable is set, and
directory> this parameter isset, the csv
metrics will be outputed here
--new-consumer Use the new consumer implementation.
This is the default.
--offset <String: consume offset> The offset id to consume from (a non-
negative number), or 'earliest'
which means from beginning, or
'latest' which means from end
(default: latest)
--partition <Integer: partition> The partition to consume from.
--property <String: prop> The properties to initialize the
message formatter.
--skip-message-on-error If there is an error when processing a
message, skip it instead of halt.
--timeout-ms <Integer: timeout_ms> If specified, exit if no message is
available for consumption for the
specified interval.
--topic <String: topic> The topic id to consume on.
--value-deserializer <String:
deserializer for values>
--whitelist <String: whitelist> Whitelist of topics to include for
consumption.
--zookeeper <String: urls> REQUIRED (only when using old
consumer): The connection string for
the zookeeper connection in the form
host:port. Multiple URLS can be
given to allow fail-over. --bootstrap-server 必须指定，通常--topic也要指定查看的主题。如果想要从头查看消息，还可以指定--from-beginning参数。一般使用的命令如下。
> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning还可以通过下面的命令指定分区查看：
>> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning --partition 0kafka-console-producer.sh
这个命令可以将文件或标准输入的内容发送到Kafka集群。该命令参数如下。
Option Description
------ -----------
--batch-size <Integer: size> Number of messages to send in a single
batch if they are not being sent
synchronously. (default: 200)
--broker-list <String: broker-list> REQUIRED: The broker list string in
the form HOST1:PORT1,HOST2:PORT2.
--compression-codec [String: The compression codec: either 'none',
compression-codec] 'gzip', 'snappy', or 'lz4'.If
specified without value, then it
defaults to 'gzip'
--key-serializer <String: The class name of the message encoder
encoder_class> implementation to use for
serializing keys. (default: kafka.
serializer.DefaultEncoder)
--line-reader <String: reader_class> The class name of the class to use for
reading lines from standard in. By
default each line is read as a
separate message. (default: kafka.
tools.
ConsoleProducer$LineMessageReader)
--max-block-ms <Long: max block on The max time that the producer will
send> block for during a send request
(default: 60000)
--max-memory-bytes <Long: total memory The total memory used by the producer
in bytes> to buffer records waiting to be sent
to the server. (default: 33554432)
--max-partition-memory-bytes <Long: The buffer size allocated for a
memory in bytes per partition> partition. When records are received
which are smaller than this size the
producer will attempt to
optimistically group them together
until this size is reached.
(default: 16384)
--message-send-max-retries <Integer> Brokers can fail receiving the message
for multiple reasons, and being
unavailable transiently is just one
of them. This property specifies the
number of retires before the
producer give up and drop this
message. (default: 3)
--metadata-expiry-ms <Long: metadata The period of time in milliseconds
expiration interval> after which we force a refresh of
metadata even if we haven't seen any
leadership changes. (default: 300000)
--old-producer Use the old producer implementation.
--producer-property <String: A mechanism to pass user-defined
producer_prop> properties in the form key=value to
the producer.
--producer.config <String: config file> Producer config properties file. Note
that [producer-property] takes
precedence over this config.
--property <String: prop> A mechanism to pass user-defined
properties in the form key=value to
the message reader. This allows
custom configuration for a user-
defined message reader.
--queue-enqueuetimeout-ms <Integer: Timeout for event enqueue (default:
queue enqueuetimeout ms> 2147483647)
--queue-size <Integer: queue_size> If set and the producer is running in
asynchronous mode, this gives the
maximum amount of messages will
queue awaiting sufficient batch
size. (default: 10000)
--request-required-acks <String: The required acks of the producer
request required acks> requests (default: 1)
--request-timeout-ms <Integer: request The ack timeout of the producer
timeout ms> requests. Value must be non-negative
and non-zero (default: 1500)
--retry-backoff-ms <Integer> Before each retry, the producer
refreshes the metadata of relevant
topics. Since leader election takes
a bit of time, this property
specifies the amount of time that
the producer waits before refreshing
the metadata. (default: 100)
--socket-buffer-size <Integer: size> The size of the tcp RECV size.
(default: 102400)
--sync If set message send requests to the
brokers are synchronously, one at a
time as they arrive.
--timeout <Integer: timeout_ms> If set and the producer is running in
asynchronous mode, this gives the
maximum amount of time a message
will queue awaiting sufficient batch
size. The value is given in ms.
(default: 1000)
--topic <String: topic> REQUIRED: The topic id to produce
messages to.
--value-serializer <String: The class name of the message encoder
encoder_class> implementation to use for
serializing values. (default: kafka.
serializer.DefaultEncoder) 其中 --broker-list 和 --topic 是两个必须提供的参数。
常用命令如下。
使用标准输入方式。
> bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test从文件读取：
> bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test < file-input.txtkafka-topics.sh
相比上面几个偶尔使用的命令来说，kafka-topics.sh 相对就比较重要。该命令包含以下参数。
Create, delete, describe, or change a topic. Option Description ------ ----------- --alter Alter the number of partitions, replica assignment, and/or configuration for the topic. --config value > A topic configuration override for the topic being created or altered.The following is a list of valid configurations: cleanup.policy compression.type delete.retention.ms file.delete.delay.ms flush.messages flush.ms follower.replication.throttled. replicas index.interval.bytes leader.replication.throttled.replicas max.message.bytes message.format.version message.timestamp.difference.max.ms message.timestamp.type min.cleanable.dirty.ratio min.compaction.lag.ms min.insync.replicas preallocate retention.bytes retention.ms segment.bytes segment.index.bytes segment.jitter.ms segment.ms unclean.leader.election.enable See the Kafka documentation for full details on the topic configs. --create Create a new topic. --delete Delete a topic --delete-config A topic configuration override to be removed for an existing topic (see the list of configurations under the --config option). --describe List details for the given topics. --disable-rack-aware Disable rack aware replica assignment --force Suppress console prompts --help Print usage information. --if-exists if set when altering or deleting topics, the action will only execute if the topic exists --if-not-exists if set when creating topics, the action will only execute if the topic does not already exist --list List all available topics. --partitions <Integer: # of partitions> 正在创建或更改主题的分区数 （警告：如果为具有密钥的主题 （分区）增加了分区 消息的逻辑或排序将受到影响 --replica-assignment of manual partition-to-broker broker_id_for_part1_replica1 : assignments for the topic being broker_id_for_part1_replica2 , created or altered. broker_id_for_part2_replica1 : broker_id_for_part2_replica2 , ...> --replication-factor <Integer: 正在创建的主题中每个分区的复制因子。 replication factor> --topic The topic to be create, alter or describe. Can also accept a regular expression except for --create option --topics-with-overrides if set when describing topics, only show topics that have overridden configs --unavailable-partitions if set when describing topics, only show partitions whose leader is not available --under-replicated-partitions if set when describing topics, only show under replicated partitions --zookeeper REQUIRED: The connection string for the zookeeper connection in the form host:port. Multiple URLS can be given to allow fail-over. 下面是几种常用的 topic 命令。
描述主题的配置
bin/kafka-configs.sh --zookeeper localhost:2181 --describe --entity-type topics --entity-name test_topic设置保留时间
# Deprecated way
bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic test_topic --config retention.ms=1000
# Modern way
bin/kafka-configs.sh --zookeeper localhost:2181 --alter --entity-type topics --entity-name test_topic --add-config retention.ms=1000如果您需要删除主题中的所有消息，则可以利用保留时间。首先将保留时间设置为非常低（1000 ms），等待几秒钟，然后将保留时间恢复为上一个值。
注意：默认保留时间为24小时（86400000毫秒）。
删除主题
bin/kafka-topics.sh --zookeeper localhost:2181 --delete --topic test_topic注意：需要在Broker的配置文件server.properties中配置 delete.topic.enable=true 才能删除主题。
主题信息
bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic test_topic添加分区
bin/kafka-topics.sh --alter --zookeeper localhost:2181 --topic test_topic --partitions 3创建主题
bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 3 --topic test_topic列出主题
bin/kafka-topics.sh --list --zookeeper localhost:2181topic 相关内容来源：http://ronnieroller.com/kafka/cheat-sheet
命令那么多，怎么记？
Kafka 的命令行工具提供了非常丰富的提示信息，所以只需要记住上面大概的几个用法，知道怎么写就行。当需要用到某个命令时，通过命令提示进行操作。
比如说，如何使用 kafka-configs.sh 查看主题（Topic）的配置？
首先，在命令行中输入bin/kafka-configs.sh，然后或输出下面的命令提示信息。
Add/Remove entity config for a topic, client, user or broker
Option Description
------ -----------
--add-config <String> Key Value pairs of configs to add. Square brackets
can be used to group values which contain commas:
'k1=v1,k2=[v1,v2,v2],k3=v3'. The following is a
list of valid configurations: For entity_type
'topics':
cleanup.policy
compression.type
delete.retention.ms
file.delete.delay.ms
flush.messages
flush.ms
follower.replication.throttled.replicas
index.interval.bytes
leader.replication.throttled.replicas
max.message.bytes
message.format.version
message.timestamp.difference.max.ms
message.timestamp.type
min.cleanable.dirty.ratio
min.compaction.lag.ms
min.insync.replicas
preallocate
retention.bytes
retention.ms
segment.bytes
segment.index.bytes
segment.jitter.ms
segment.ms
unclean.leader.election.enable
For entity_type 'brokers':
follower.replication.throttled.rate
leader.replication.throttled.rate
For entity_type 'users':
producer_byte_rate
SCRAM-SHA-256
SCRAM-SHA-512
consumer_byte_rate
For entity_type 'clients':
producer_byte_rate
consumer_byte_rate
Entity types 'users' and 'clients' may be specified
together to update config for clients of a
specific user.
--alter Alter the configuration for the entity.
--delete-config <String> config keys to remove 'k1,k2'
--describe List configs for the given entity.
--entity-default Default entity name for clients/users (applies to
corresponding entity type in command line)
--entity-name <String> Name of entity (topic name/client id/user principal
name/broker id)
--entity-type <String> Type of entity (topics/clients/users/brokers)
--force Suppress console prompts
--help Print usage information.
--zookeeper <String: urls> REQUIRED: The connection string for the zookeeper
connection in the form host:port. Multiple URLS
can be given to allow fail-over.从第一行可以看到这个命令可以修改 topic, client, user 或 broker 的配置。
如果要设置 topic，就需要设置 entity-type 为topics，输入如下命令：
> bin/kafka-configs.sh --entity-type topics
Command must include exactly one action: --describe, --alter命令提示需要指定一个操作（不只是上面提示的两个操作），增加--describe试试：
> bin/kafka-configs.sh --entity-type topics --describe
[root@localhost kafka_2.11-0.10.2.1]# bin/kafka-configs.sh --entity-type topics --describe
Missing required argument "[zookeeper]"继续增加 --zookeeper：
> bin/kafka-configs.sh --entity-type topics --describe --zookeeper localhost:2181
Configs for topic '__consumer_offsets' are segment.bytes=104857600,cleanup.policy=compact,compression.type=producer由于没有指定主题名，这里显示了__consumer_offsets的信息。下面指定一个topic试试。
> bin/kafka-configs.sh --entity-type topics --describe --zookeeper localhost:2181 --entity-name test
Configs for topic 'test' are此时显示了test主题的信息，这里是空。
因为Kafka完善的命令提示，可以很轻松的通过提示信息来进行下一步操作，运用熟练后，基本上很快就能实现自己想要的命令。