[KAFKA-620] UnknownHostError looking for a ZK node crashes the broker

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 0.7.1
• Component/s: core
• Environment: linux. Amazon's AMI
• Assignee: Unassigned
• Reporter: Matthew Rathbone
• Created: 16/Nov/12 16:45
• Updated: 08/Feb/15 06:17
• Resolved: 08/Feb/15 06:17

Description

If you totally kill a zookeeper node so that it's hostname no longer resolves to anything, the broker will die with a java.net.UnknownHostException.

You will then be unable to restart the broker until the unknown host(s) is removed from the server.properties.

We ran into this issue while testing our resilience to widespread AWS outages, if you can point me to the right place, I could have a go at fixing it? Unfortunately, I suspect the issue might be in the non-standard Zookeeper library that kafka uses.

Here's the stack trace:
org.I0Itec.zkclient.exception.ZkException: Unable to connect to [list of zookeepers]
at org.I0Itec.zkclient.ZkConnection.connect(ZkConnection.java:66)
at org.I0Itec.zkclient.ZkClient.connect(ZkClient.java:872)
at org.I0Itec.zkclient.ZkClient.<init>(ZkClient.java:98)
at org.I0Itec.zkclient.ZkClient.<init>(ZkClient.java:84)
at kafka.server.KafkaZooKeeper.startup(KafkaZooKeeper.scala:44)
at kafka.log.LogManager.<init>(LogManager.scala:87)
at kafka.server.KafkaServer.startup(KafkaServer.scala:58)
at kafka.server.KafkaServerStartable.startup(KafkaServerStartable.scala:34)
at kafka.Kafka$.main(Kafka.scala:50)
at kafka.Kafka.main(Kafka.scala)
Caused by: java.net.UnknownHostException: zk-101
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:850)
at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1201)
at java.net.InetAddress.getAllByName0(InetAddress.java:1154)
at java.net.InetAddress.getAllByName(InetAddress.java:1084)
at java.net.InetAddress.getAllByName(InetAddress.java:1020)
at org.apache.zookeeper.ClientCnxn.<init>(ClientCnxn.java:387)
at org.apache.zookeeper.ClientCnxn.<init>(ClientCnxn.java:332)
at org.apache.zookeeper.ZooKeeper.<init>(ZooKeeper.java:383)
at org.I0Itec.zkclient.ZkConnection.connect(ZkConnection.java:64)
... 9 more

Issue Links

• duplicates: KAFKA-1082 zkclient dies after UnknownHostException in zk reconnect