我必须在kafka中添加ssl加密和身份验证。
我就是这么做的：
为每个代理生成证书kafka: keytool -keystore server.keystore.jks -alias localhost -validity 365 -genkey 创建ca。生成的ca是一个公私密钥对和用于签署其他证书的证书。ca负责签署证书。 openssl req -new -x509 -keyout ca-key -out ca-cert -days 365 使用生成的ca签署所有代理证书从密钥库导出证书： keytool -keystore server.keystore.jks -alias localhost -certreq -file cert-file 与ca签署： openssl x509 -req -CA ca-cert -CAkey ca-key -in cert-file -out cert-signed -days {validity} -CAcreateserial -passin pass:{ca-password} 将ca的证书和已签名的证书导入密钥库：
keytool -keystore server.keystore.jks -alias CARoot -import -file ca-cert keytool -keystore server.keystore.jks -alias localhost -import -file cert-signed 将ca导入客户端信任库和代理/服务器信任库：
keytool -keystore server.truststore.jks -alias CARoot -import -file ca-cert keytool -keystore client.truststore.jks -alias CARoot -import -file ca-cert 在configuration server.properties中添加以下行： listeners=PLAINTEXT://localhost:9092, SSL://localhost:9192 ssl.client.auth=required ssl.keystore.location=/home/xrobot/kafka_2.12-2.1.0/certificate/server.keystore.jks ssl.keystore.password=blablabla ssl.key.password=blablabla ssl.truststore.location=/home/xrobot/kafka_2.12-2.1.0/certificate/server.truststore.jks ssl.truststore.password=blablabla security.inter.broker.protocol=SSL 问题是，当我开始Kafka，然后我得到这个错误：

[2019-02-26 19:03:59,783] INFO [KafkaServer id=0] started (kafka.server.KafkaServer)
[2019-02-26 19:04:00,011] ERROR [Controller id=0, targetBrokerId=0] Connection to node 0 (localhost/127.0.0.1:9192) failed authentication due to: SSL handshake failed (org.apache.kafka.clients.NetworkClient)
[2019-02-26 19:04:00,178] ERROR [Controller id=0, targetBrokerId=0] Connection to node 0 (localhost/127.0.0.1:9192) failed authentication due to: SSL handshake failed (org.apache.kafka.clients.NetworkClient)
[2019-02-26 19:04:00,319] ERROR [Controller id=0, targetBrokerId=0] Connection to node 0 (localhost/127.0.0.1:9192) failed authentication due to: SSL handshake failed (org.apache.kafka.clients.NetworkClient)

为什么？
编辑：server.properties:

# 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
############################# 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://localhost:9092, SSL://localhost:9192
ssl.client.auth=required
ssl.keystore.location=/home/xrobot/kafka_2.12-2.1.0/certificate/server.keystore.jks
ssl.keystore.password=onailime
ssl.key.password=onailime
ssl.truststore.location=/home/xrobot/kafka_2.12-2.1.0/certificate/server.truststore.jks
ssl.truststore.password=onailime
security.inter.broker.protocol=SSL
# 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
# 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=/home/xrobot/kafka_2.12-2.1.0/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.
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

zookeeper.properties属性：

# 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.
# the directory where the snapshot is stored.
dataDir=/home/xrobot/kafka_2.12-2.1.0/data/zookeeper
# the port at which the clients will connect
clientPort=2181
# disable the per-ip limit on the number of connections since this is a non-production config
maxClientCnxns=0