Apache Kafka 入门 - Kafka命令详细介绍

ゞ浴缸里的玫瑰 2022-06-13 03:10 290阅读 0赞

# 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 0

### kafka-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.txt

### kafka-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 <String: name=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 <String: name> 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 <String: A list 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 <String: 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 <String: urls> 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:2181

> topic 相关内容来源：[http://ronnieroller.com/kafka/cheat-sheet][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。

[Broker Configs]: https://kafka.apache.org/documentation/#brokerconfigs
[http_ronnieroller.com_kafka_cheat-sheet]: http://ronnieroller.com/kafka/cheat-sheet