# Licensed to the Apache Software Foundation (ASF) under one or more  # contributor license agreements.  See the NOTICE file distributed with  # this work for additional information regarding copyright ownership.  # The ASF licenses this file to You under the Apache License, Version 2.0  # (the "License"); you may not use this file except in compliance with  # the License.  You may obtain a copy of the License at  #  #    http://www.apache.org/licenses/LICENSE-2.0  #  # Unless required by applicable law or agreed to in writing, software  # distributed under the License is distributed on an "AS IS" BASIS,  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  # See the License for the specific language governing permissions and  # limitations under the License.  # see kafka.server.KafkaConfig for additional details and defaults    ############################# Server Basics #############################    ##################################################################################  #  broker就是一個kafka的部署實例，在一個kafka集群中，每一台kafka都要有一個broker.id  #  並且，該id唯一，且必須為整數  ##################################################################################  broker.id=10    ############################# 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 = security_protocol://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    ##################################################################################  #The number of threads handling network requests  # 默認處理網路請求的執行緒個數 3個  ##################################################################################  num.network.threads=3  ##################################################################################  # The number of threads doing disk I/O  # 執行磁碟IO操作的默認執行緒個數 8  ##################################################################################  num.io.threads=8    ##################################################################################  # The send buffer (SO_SNDBUF) used by the socket server  # socket服務使用的進行發送數據的緩衝區大小，默認100kb  ##################################################################################  socket.send.buffer.bytes=102400    ##################################################################################  # The receive buffer (SO_SNDBUF) used by the socket server  # socket服務使用的進行接受數據的緩衝區大小，默認100kb  ##################################################################################  socket.receive.buffer.bytes=102400    ##################################################################################  # The maximum size of a request that the socket server will accept (protection against OOM)  # socket服務所能夠接受的最大的請求量，防止出現OOM(Out of memory)記憶體溢出，默認值為：100m  # （應該是socker server所能接受的一個請求的最大大小，默認為100M）  ##################################################################################  socket.request.max.bytes=104857600    ############################# Log Basics （數據相關部分，kafka的數據稱為log）#############################    ##################################################################################  # A comma seperated list of directories under which to store log files  # 一個用逗號分隔的目錄列表，用於存儲kafka接受到的數據  ##################################################################################  log.dirs=/home/uplooking/data/kafka    ##################################################################################  # 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.  # 每一個topic所對應的log的partition分區數目，默認1個。更多的partition數目會提高消費  # 並行度，但是也會導致在kafka集群中有更多的文件進行傳輸  # （partition就是分散式存儲，相當於是把一份數據分開幾份來進行存儲，即劃分塊、劃分分區的意思）  ##################################################################################  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.  # 每一個數據目錄用於在啟動kafka時恢複數據和在關閉時刷新數據的執行緒個數。如果kafka數據存儲在磁碟陣列中  # 建議此值可以調整更大。  ##################################################################################  num.recovery.threads.per.data.dir=1    ############################# Log Flush Policy （數據刷新策略）#############################    # 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（平衡） here:  #    1. Durability 持久性: Unflushed data may be lost if you are not using replication.  #    2. Latency 延時性: 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 吞吐量: The flush is generally the most expensive operation, and a small flush interval may lead to exceessive 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.  # kafka中只有基於消息條數和時間間隔數來制定數據刷新策略，而沒有大小的選項，這兩個選項可以選擇配置一個  # 當然也可以兩個都配置，默認情況下兩個都配置，配置如下。    # The number of messages to accept before forcing a flush of data to disk  # 消息刷新到磁碟中的消息條數閾值  #log.flush.interval.messages=10000    # The maximum amount of time a message can sit in a log before we force a flush  # 消息刷新到磁碟生成一個log數據文件的時間間隔  #log.flush.interval.ms=1000    ############################# Log Retention Policy（數據保留策略） #############################    # The following configurations control the disposal（清理） of log segments（分片）. The policy can  # be set to delete segments after a period of time, or after a given size has accumulated（累積）.  # A segment will be deleted whenever（無論什麼時間） *either* of these criteria（標準） are met. Deletion always happens  # from the end of the log.  # 下面的配置用於控制數據片段的清理，只要滿足其中一個策略（基於時間或基於大小），分片就會被刪除    # The minimum age of a log file to be eligible for deletion  # 基於時間的策略，刪除日誌數據的時間，默認保存7天  log.retention.hours=168    # A size-based retention policy for logs. Segments are pruned from the log as long as the remaining  # segments don't drop below log.retention.bytes. 1G  # 基於大小的策略，1G  #log.retention.bytes=1073741824    # The maximum size of a log segment file. When this size is reached a new log segment will be created.  # 數據分片策略  log.segment.bytes=1073741824    # The interval at which log segments are checked to see if they can be deleted according  # to the retention policies 5分鐘  # 每隔多長時間檢測數據是否達到刪除條件  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=uplooking01:2181,uplooking02:2181,uplooking03:2181    # Timeout in ms for connecting to zookeeper  zookeeper.connection.timeout.ms=6000