背景
系统订单创建成功之后需要发送订单创建成功的消息，但是今天突然遇到了如下的报错
org.apache.rocketmq.client.exception.MQClientException: No route info of this topic, TopicTest
See http://rocketmq.apache.org/docs/faq/ for further details.
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.sendDefaultImpl(DefaultMQProducerImpl.java:610)
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.send(DefaultMQProducerImpl.java:1223)
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.send(DefaultMQProducerImpl.java:1173)
at org.apache.rocketmq.client.producer.DefaultMQProducer.send(DefaultMQProducer.java:214)
探究
出现上面的错误，主要有三种情况
一：Topic不存在，即没有创建出来次Topic(我们项目均为手动创建)，或者Broker模块不支持自动创建topic。
二：Broker模块没有正确连接到Name Server
三：Producer没有正确连接到Name Server
办法
排查1：Broker 禁止自动创建 Topic，且用户没有通过手工方式创建 Topic
可以在 Rocket_HOME/distribution/target/apache-rocketmq 下执行 " sh bin/mqbroker -m " 来查看 broker 的配置参数
如下所示，autoCreateTopicEnable=true 证明是没有问题的
[root@localhost apache-rocketmq]# sh ./bin/mqbroker -m 2018-08-12 01\:27\:28 INFO main - namesrvAddr= 2018-08-12 01\:27\:28 INFO main - brokerIP1=192.168.58.129 2018-08-12 01\:27\:28 INFO main - brokerName=localhost.localdomain 2018-08-12 01\:27\:28 INFO main - brokerClusterName=DefaultCluster 2018-08-12 01\:27\:28 INFO main - brokerId=0 2018-08-12 01\:27\:28 INFO main - autoCreateTopicEnable=true 2018-08-12 01\:27\:28 INFO main - autoCreateSubscriptionGroup=true 2018-08-12 01\:27\:28 INFO main - rejectTransactionMessage=false 2018-08-12 01\:27\:28 INFO main - fetchNamesrvAddrByAddressServer=false 2018-08-12 01\:27\:28 INFO main - transactionTimeOut=3000 2018-08-12 01\:27\:28 INFO main - transactionCheckMax=5 2018-08-12 01\:27\:28 INFO main - transactionCheckInterval=60000 2018-08-12 01\:27\:28 INFO main - storePathRootDir=/root/store 2018-08-12 01\:27\:28 INFO main - storePathCommitLog=/root/store/commitlog 2018-08-12 01\:27\:28 INFO main - flushIntervalCommitLog=500 2018-08-12 01\:27\:28 INFO main - commitIntervalCommitLog=200 2018-08-12 01\:27\:28 INFO main - flushCommitLogTimed=false 2018-08-12 01\:27\:28 INFO main - deleteWhen=04 2018-08-12 01\:27\:28 INFO main - fileReservedTime=72 2018-08-12 01\:27\:28 INFO main - maxTransferBytesOnMessageInMemory=262144 2018-08-12 01\:27\:28 INFO main - maxTransferCountOnMessageInMemory=32 2018-08-12 01\:27\:28 INFO main - maxTransferBytesOnMessageInDisk=65536 2018-08-12 01\:27\:28 INFO main - maxTransferCountOnMessageInDisk=8 2018-08-12 01\:27\:28 INFO main - accessMessageInMemoryMaxRatio=40 2018-08-12 01\:27\:28 INFO main - messageIndexEnable=true 2018-08-12 01\:27\:28 INFO main - messageIndexSafe=false 2018-08-12 01\:27\:28 INFO main - haMasterAddress= 2018-08-12 01\:27\:28 INFO main - brokerRole=ASYNC_MASTER 2018-08-12 01\:27\:28 INFO main - flushDiskType=ASYNC_FLUSH 2018-08-12 01\:27\:28 INFO main - cleanFileForciblyEnable=true 2018-08-12 01\:27\:28 INFO main - transientStorePoolEnable=false [root@localhost apache-rocketmq]#
排查2：Broker 没有正确连接到 Name Server
如下所示，启动 broker 的时候，只要看到了 The broker[localhost.localdomain, 192.168.58.129:10911] boot success. serializeType=JSON and name server is localhost:9876 字样就说明是成功的
[root@localhost apache-rocketmq]# nohup sh bin/mqbroker -n localhost:9876 & [2] 3256 [1] 退出 143 nohup sh bin/mqbroker -n localhost:9876 [root@localhost apache-rocketmq]# nohup: 忽略输入并把输出追加到"nohup.out" tail -f ~/logs/rocketmqlogs/broker.log 2018-08-11 23:48:26 INFO main - load exist subscription group, SubscriptionGroupConfig [groupName=CID_ONSAPI_OWNER, consumeEnable=true, consumeFromMinEnable=true, consumeBroadcastEnable=true, retryQueueNums=1, retryMaxTimes=16, brokerId= 2018-08-11 23:48:31 WARN main - Load default discard message hook service: DefaultTransactionalMessageCheckListener 2018-08-11 23:48:31 INFO FileWatchService - FileWatchService service started 2018-08-11 23:48:31 INFO PullRequestHoldService - PullRequestHoldService service started 2018-08-11 23:48:31 INFO brokerOutApi_thread_1 - register broker to name server localhost:9876 OK 2018-08-11 23:48:31 INFO main - Start transaction service! 2018-08-11 23:48:31 INFO main - The broker[localhost.localdomain, 192.168.58.129:10911] boot success. serializeType=JSON and name server is localhost:9876 2018-08-11 23:48:41 INFO BrokerControllerScheduledThread1 - dispatch behind commit log 0 bytes 2018-08-11 23:48:41 INFO BrokerControllerScheduledThread1 - Slave fall behind master: 906412 bytes 2018-08-11 23:48:41 INFO brokerOutApi_thread_2 - register broker to name server localhost:9876 OK
排查3：Producer 没有正确连接到 Name Server
如果按前两步检查没有问题，但启动还是报错，那就只剩下第三种情况了，最大可能是发送者和mq服务器之间的网络或端口不通，可以使用ping或者telnet确定问题。如果ping或者telnet连接不通，则说明producer无法连接到nameserver，很可能是防火墙的原因 ，需要联系运维工程师开通网络或端口权限。
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