一、環(huán)境搭建
kafka的搭建依賴zookeeper，所以我們先配置zookeeper
# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/home/mq/zkdata
# the port at which the clients will connect
clientPort=2181
server.1=172.18.182.32:2888:3888
server.2=172.18.182.33:2888:3888
server.3=172.18.182.31:2888:3888
zookeeper正常啟動后用zkServer.sh status查看狀態(tài)。
然后配置Kafka的server.properties文件.
############################# Server Basics #############################
# The id of the broker. This must be set to a unique integer for each broker.
broker.id=0
delete.topic.enable=true
############################# Socket Server Settings #############################
# The address the socket server listens on. It will get the value returned from
# java.net.InetAddress.getCanonicalHostName() if not configured.
# FORMAT:
# listeners = listener_name://host_name:port
# EXAMPLE:
# listeners = PLAINTEXT://your.host.name:9092
listeners=PLAINTEXT://:9092
# Hostname and port the broker will advertise to producers and consumers. If not set,
# it uses the value for "listeners" if configured. Otherwise, it will use the value
# returned from java.net.InetAddress.getCanonicalHostName().
#advertised.listeners=PLAINTEXT://your.host.name:9092
advertised.listeners=PLAINTEXT://172.18.182.32:9092
port=9092
host.name=172.18.182.32
# Maps listener names to security protocols, the default is for them to be the same. See the config documentation for more details
#listener.security.protocol.map=PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL
# The number of threads that the server uses for receiving requests from the network and sending responses to the network
num.network.threads=3
# The number of threads that the server uses for processing requests, which may include disk I/O
num.io.threads=8
# The send buffer (SO_SNDBUF) used by the socket server
socket.send.buffer.bytes=102400
# The receive buffer (SO_RCVBUF) used by the socket server
socket.receive.buffer.bytes=102400
# The maximum size of a request that the socket server will accept (protection against OOM)
socket.request.max.bytes=104857600
############################# Log Basics #############################
# A comma separated list of directories under which to store log files
log.dirs=/tmp/kafka-logs
# The default number of log partitions per topic. More partitions allow greater
# parallelism for consumption, but this will also result in more files across
# the brokers.
num.partitions=1
# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
# This value is recommended to be increased for installations with data dirs located in RAID array.
num.recovery.threads.per.data.dir=1
############################# Internal Topic Settings #############################
# The replication factor for the group metadata internal topics "__consumer_offsets" and "__transaction_state"
# For anything other than development testing, a value greater than 1 is recommended to ensure availability such as 3.
offsets.topic.replication.factor=1
transaction.state.log.replication.factor=1
transaction.state.log.min.isr=1
############################# Log Flush Policy #############################
# Messages are immediately written to the filesystem but by default we only fsync() to sync
# the OS cache lazily. The following configurations control the flush of data to disk.
# There are a few important trade-offs here:
# 1. Durability: Unflushed data may be lost if you are not using replication.
# 2. Latency: Very large flush intervals may lead to latency spikes when the flush does occur as there will be a lot of data to flush.
# 3. Throughput: The flush is generally the most expensive operation, and a small flush interval may lead to excessive seeks.
# The settings below allow one to configure the flush policy to flush data after a period of time or
# every N messages (or both). This can be done globally and overridden on a per-topic basis.
# The number of messages to accept before forcing a flush of data to disk
#log.flush.interval.messages=10000
# The maximum amount of time a message can sit in a log before we force a flush
#log.flush.interval.ms=1000
############################# Log Retention Policy #############################
# The following configurations control the disposal of log segments. The policy can
# be set to delete segments after a period of time, or after a given size has accumulated.
# A segment will be deleted whenever *either* of these criteria are met. Deletion always happens
# from the end of the log.
# The minimum age of a log file to be eligible for deletion due to age
log.retention.hours=168
# A size-based retention policy for logs. Segments are pruned from the log unless the remaining
# segments drop below log.retention.bytes. Functions independently of log.retention.hours.
#log.retention.bytes=1073741824
# The maximum size of a log segment file. When this size is reached a new log segment will be created.
log.segment.bytes=1073741824
# The interval at which log segments are checked to see if they can be deleted according
# to the retention policies
log.retention.check.interval.ms=300000
############################# Zookeeper #############################
# Zookeeper connection string (see zookeeper docs for details).
# This is a comma separated host:port pairs, each corresponding to a zk
# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002".
# You can also append an optional chroot string to the urls to specify the
# root directory for all kafka znodes.
zookeeper.connect=172.18.182.32:2181,172.18.182.33:2181,172.18.182.31:2181
# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=6000
############################# Group Coordinator Settings #############################
# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.
# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.
# The default value for this is 3 seconds.
# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.
# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.
group.initial.rebalance.delay.ms=0
之后啟動三臺kafka
/bin/kafka-server-start.sh -daemon kafka_2.12-2.4.0/config/server.properties
如果jps發(fā)現(xiàn)沒啟動，前臺啟動查看報錯日志，或者取kafka/logs里面查看.
二、常用命令
# 啟動kafka
bin/kafka-server-start.sh -daemon config/server.properties
# 創(chuàng)建一個topic
bin/kafka-topics.sh --create --bootstrap-server 172.18.182.32:2181,172.18.182.33:2181,172.18.182.31:2181 --replication-factor 2 --partitions 2 --topic queuing-user-create
# topic列表
bin/kafka-topics.sh --list --zookeeper 172.18.182.32:2181,172.18.182.33:2181,172.18.182.31:2181
# topic描述，如果加--topic則可以看某個topic
# PartitionCount：分區(qū)數(shù)量，ReplicationFactor：副本數(shù)量，Partition：分區(qū)編號，Leader：是否是負責讀寫的分區(qū)，如果只有一個則為None，Replicas：這個分區(qū)的副本在哪些節(jié)點，Isr：數(shù)據(jù)已同步的節(jié)點。
bin/kafka-topics.sh --describe --zookeeper 172.18.182.32:2181,172.18.182.33:2181,172.18.182.31:2181
Topic: queuing-survey-answer-status PartitionCount: 2 ReplicationFactor: 2 Configs:
Topic: queuing-survey-answer-status Partition: 0 Leader: 1 Replicas: 1,2 Isr: 1
Topic: queuing-survey-answer-status Partition: 1 Leader: 0 Replicas: 2,0 Isr: 0
Topic: queuing-survey-anwser PartitionCount: 1 ReplicationFactor: 1 Configs:
Topic: queuing-survey-anwser Partition: 0 Leader: none Replicas: 2 Isr: 2
# 開啟一個調(diào)試生產(chǎn)者
bin/kafka-console-producer.sh --broker-list 172.18.182.32:2181,172.18.182.33:2181,172.18.182.31:2181 --topic queuing-survey-anwser
# 開啟一個調(diào)試消費者，也可以9092
bin/kafka-console-consumer.sh --bootstrap-server 172.18.182.32:2181,172.18.182.33:2181,172.18.182.31:2181 --topic queuing-user-create --from-beginning
# 日志查看
bin/kafka-run-class.sh kafka.tools.DumpLogSegments --files /tmp/kafka-logs/queuing-survey-answer-status-1/00000000000000000000.log --print-data-log
# 消費組查看
bin/kafka-consumer-groups.sh --bootstrap-server 172.18.182.32:9092,172.18.182.33:9092,172.18.182.31:9092 --group UserCenterProd --describe
# 手動設(shè)置offset
bin/kafka-consumer-groups.sh --bootstrap-server 172.18.182.32:9092,172.18.182.33:9092,172.18.182.31:9092 --group UserCenterProd --reset-offsets --topic queuing-user-add --to-offset 20 --execute
三、基礎(chǔ)概念
- broker：即節(jié)點
- partition：分區(qū)，消息會根據(jù)key進入不同的分區(qū)，由不同的消費者（也可以相同，自動分配）消費。
--replication-factor：備份，一般小于等于broker的數(shù)量。 - ISR：leader會追蹤和維護ISR中所有follower的滯后狀態(tài)。如果滯后太多（數(shù)量滯后和時間滯后兩個維度，replica.lag.time.max.ms和replica.lag.max.message可配置），leader會把該replica從ISR中移除。被移除ISR的replica一直在追趕leader。如下圖，leader寫入數(shù)據(jù)后并不會commit，只有ISR列表中的所有folower同步之后才會commit，把滯后的follower移除ISR主要是避免寫消息延遲。設(shè)置ISR主要是為了broker宕掉之后，重新選舉partition的leader從ISR列表中選擇。（轉(zhuǎn)自 https://blog.csdn.net/dshf_1/article/details/82467558 ）
- consumer group: 同一個消費組中的不同消費者負責topic的一部分partition；如果是不同消費組，則獨立計算offset，即對一個topic消費多次。
- zookeeper：分布式協(xié)調(diào)框架，負責協(xié)調(diào)管理并保存kafka的元數(shù)據(jù)，比如哪些broker在運行，創(chuàng)建了哪些topic，它們有哪些分區(qū)，leader在哪。
四、集群環(huán)境建議
| 因素 | 考量點 | 建議 |
|---|---|---|
| 操作系統(tǒng) | 操作系統(tǒng)I/O模型 | Linux |
| 磁盤 | 磁盤I/O性能 | 普通機械硬盤，不需要RAID |
| 磁盤容量 | 根據(jù)消息量和留存時間預估 | 建議多預留30%空間 |
| 帶寬 | 根據(jù)業(yè)務(wù) | 如果千兆貸款，建議按照700Mbps來計算 |
五、最重要的集群參數(shù)配置
1）broker端參數(shù)
| 參數(shù) | 設(shè)置建議 | 概述 |
|---|---|---|
| log.dir | 可以不設(shè)置 | 一般設(shè)置log.dirs |
| log.dirs | /home/kafka1,/home/kafka2 | 設(shè)置在不同的物理磁盤上可以提升讀寫性能，實現(xiàn)failover |
| zookeeper.connect | zk1:2181,zk2:2181,zk2:2181/kafka1 | 可以多個kafka集群共用一個zk集群 |
| listeners | 協(xié)議://HOST_NAME:9092 | 外部連接要通過什么協(xié)議訪問指定主機名和端口開放的kafka服務(wù) |
| advertised.listeners | 協(xié)議://HOST_NAME:9092 | 這組監(jiān)聽器是Broker用于對外發(fā)布的，會存在zookeeper中 |
| host.name/port | 空 | 不要填這兩個，早就不用了 |
| auto.create.topics.enable | false | 不要開啟自動創(chuàng)建 |
| unclean.leader.election.enable | false | 不要unclean選舉 |
| auto.leader.rebalance.enable | false | 關(guān)閉定時選舉 |
| log.retention.hours | 168 | 數(shù)據(jù)保存7天 |
| log.retention.bytes | 根據(jù)空閑硬盤設(shè)定 | 防止服務(wù)器爆 |
| message.max.bytes | 1000120 | kafka最大消息大小，默認是100012 |
2）topic端參數(shù)
| 參數(shù) | 設(shè)置建議 | 概述 |
|---|---|---|
| retention.ms | 數(shù)據(jù)保存時間 | |
| retention.bytes | 預留空間 | |
| max.message.bytes | 1000120 | kafka最大消息大小，默認是100012 |
| replica.fetch.max.bytes | 1000120 | 根據(jù)max.message.bytes設(shè)置保證復制 |
| fetch.message.max.bytes | 1000120 | 根據(jù)max.message.bytes設(shè)置保證消費 |
3）JVM參數(shù)
在啟動kafka前配置java的默認堆大小
$> export KAFKA_HEAP_OPTS=--Xms6g --Xmx6g
$> export KAFKA_JVM_PERFORMANCE_OPTS= -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+ExplicitGCInvokesConcurrent -Djava.awt.headless=true
$> bin/kafka-server-start.sh config/server.properties
4）操作系統(tǒng)參數(shù)
ulimit -n 1000000
文件系統(tǒng)可以選擇XFS
swappiess設(shè)置為1
落盤時間可以適當延長
