UnresolvedAddressException being hit by Druid brok

Question

I'm new to Druid. I've set up a cluster using the Imply IAP package. Events are being ingested into Druid from Kafka using Tranquility. I can see that the events are being accepted by Tranquility - the following log statements are what I used to verify that:

2016-10-03 19:19:22,715 [KafkaConsumer-CommitThread] INFO  c.m.tranquility.kafka.KafkaConsumer - Flushed {conn_recs={receivedCount=1, sentCount=1, droppedCount=0, unparseableCount=0}} pending messages in 32056ms and committed offsets in 15ms.

However, the broker seems to be hitting an exception when I try running a timeBoundary query on the datasource.

Following is the exception stack trace (copied from the broker's log):

java.nio.channels.UnresolvedAddressException
  at sun.nio.ch.Net.checkAddress(Net.java:101) ~[?:1.8.0_66]
  at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:622) ~[?:1.8.0_66]
  at org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink.connect(NioClientSocketPipelineSink.java:108) [netty-3.10.4.Final.jar:?]
  at org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink.eventSunk(NioClientSocketPipelineSink.java:70) [netty-3.10.4.Final.jar:?]
  at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendDownstream(DefaultChannelPipeline.java:779) [netty-3.10.4.Final.jar:?]
  at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.handleDownstream(OneToOneEncoder.java:54) [netty-3.10.4.Final.jar:?]

I've been stuck at this point for while since I'm not sure which logs/processes I need to look into to further debug this.

Question: Could someone explain how I need to go about debugging such an issue - ie, any specific logs I need to look at, etc.?

Btw, I'm using a separate 3-node zookeeper cluster and a single node mysql instance as external dependencies for the druid cluster.

Please let me know if I need to provide more information.

Thanks, Jithin

Answer 1

1. Tranquility goes to zookeeper and gets overlord's DNS name.
2. Tranquility tries to connect to the overlord and then you get UnresolvedAddressException.

You need to setup DNS or to do something to be able to resolve IP address by hostname.