docker kafka 外网访问不到

linux虚拟机中的kafka docker 容器外网显示：

原因：

kafka的外网IP端口配置参数设置错误。

原--》设置了容器的IP端口。

改--》设置宿主机的ip以及宿主机上的端口。

摘取：

Kafka跨网络访问设置

 

实际场景：

• kafka应用通过docker进行部署并暴露出不同kafka节点到不同的指定端口；
• 业务系统通过虚拟机进行部署；
• docker宿主机与业务系统在同一个局域网；

报错：

• 业务系统连接kafka时返回docker kafka服务名及原端口（9092）

• can not found the leader of kafka

原因：

1. 　kafka配置文件server.properties中，host.name只绑定在了内部的IP上面，对外的网卡无法访问，及在物理业务系统服务器上面并不能识别到kafka服务名；
2. 　把值设置为空的话会kafka监听端口在所有的网卡上绑定。但是在外网访问时，客户端又遇到了“java.nio.channels.ClosedChannelException”异常信息，server端用tcpdump分析的时候发现客户端有传递kafka所在容器的服务名过来。在client里断点跟踪一下发现是findLeader的时候返回的元信息是容器服务名而不是IP。业务系统客户端无法解析这个机器名所以出现了前面的异常。

　　在server.properties 里还有另一个参数是解决这个问题的， advertised.host.name参数用来配置返回的host.name值，把这个参数配置为局域网IP地址即可。

这个参数默认没有启用，默认是返回的java.net.InetAddress.getCanonicalHostName的值。

　　除了IP之外，还有PORT，外网对应的PORT也需要修改。

　　以下是server.properties文件对应位置。

　　针对docker容器可以用环境变量参数将具体的参数传递进去：

 

　　KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://xxx.xxx.xxx.xxx：port （局域网宿主机的IP地址而非容器的IP，及暴露出来的端口）

 

　　针对局域网向公网IP端口暴露的话，这修改配置文件,加入以下配置：

　　

　　advertised.listeners=PLAINTEXT://xxx.xxx.xxx.xxx:port

　　

　　当Kafka broker启动时，它会在ZK上注册自己的IP和端口号，客户端就通过这个IP和端口号来连接。此时就需要显示指定 advertised.host.name, advertised.listeners参数，让注册到ZK上的IP是外外部IP。需要在 server.properties 配置文件里增加如下配置（版本0.10.x broker及之后的新版本）：

　　新版本0.10.x broker配置弃用了advertised.host.name和 advertised.port这两个个配置项，就配置advertised.listeners就可以了。

参考文章：

Kafka跨网络访问设置

配置文件的内容：

# 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 #############################

# The id of the broker. This must be set to a unique integer for each broker.
broker.id=0

# add my config kongfanjun
#port=9092
#端口号
#host.name=127.0.0.1
#服务器IP地址，修改为自己的服务器IP
log.dirs=/usr/local/kafka_2.11-1.1.0/logs
#日志存放路径，上面创建的目录
zookeeper.connect=localhost:2181
#zookeeper地址和端口，单机配置部署，localhost:2181

############################# 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://192.168.153.133:3092

# 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 for 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=localhost: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