问题来源

同事在一次spark程序中，通过spark在kafka中的topic中写入数据发生报错，错误日志如下:

2021-01-25 19:58:11,794 INFO utils.AppInfoParser: Kafka version : 2.0.0-cdh6.1.1
2021-01-25 19:58:11,794 INFO utils.AppInfoParser: Kafka commitId : null
2021-01-25 19:58:11,984 INFO codegen.CodeGenerator: Code generated in 80.049669 ms
2021-01-25 19:58:12,020 WARN clients.NetworkClient: [Producer clientId=producer-1] Connection to node -3 could not be established. Broker may not be available.
2021-01-25 19:58:12,034 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 4 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,034 INFO clients.Metadata: Cluster ID: aKKlHlDqQtalfjbLYRW1GQ
2021-01-25 19:58:12,136 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 9 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,241 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 10 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,346 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 11 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,451 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 12 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,554 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 13 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,658 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 14 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,763 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 15 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,867 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 16 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:12,971 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 17 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,076 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 18 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,181 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 19 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,285 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 20 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,390 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 21 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,495 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 22 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,600 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 23 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,704 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 24 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,808 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 25 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:13,913 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 26 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:14,044 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 27 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:14,149 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 28 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}
2021-01-25 19:58:14,254 WARN clients.NetworkClient: [Producer clientId=producer-1] Error while fetching metadata with correlation id 29 : {tagging-api-1611575841019=INVALID_REPLICATION_FACTOR}

探索步骤:

1. 根据日志中的信息：INVALID_REPLICATION_FACTOR 初步判断，出现了不合法的副本数。
2. 检查kafka的配置文件发现server.properties中默认的配置是三副本配置。
3. 检查被写入kafka的topic是否存在，发现目标topic并不存在，初步怀疑是建立topic失败
4. 得知同事以前可以在这个kafka的集群中成功执行同样的任务，遂后开始检查kafka集群的状态。
5. 检查出有一台的kafka的broker结点挂掉，重启失败。发现是磁盘空间被占空导致重启失败，遂清理无用日志空出空间，启动kakfa发现kafka成功执行没有失败
6. 同事再次启动程序，这个时候已经可以成功运行了。问题解决√

总结

在水下这篇文章之前，看了下报错日志。其中日志里提到了这样的一句话:Connection to node -3 could not be established. Broker may not be available.，所以，emmmm，如果仔细一下日志的话，可以更加快速的定位到问题。所以，我再次记录一下这个文章的目的是为了警醒自己，一定要仔细看日志，仔细看日志。