[jira] [Created] (KAFKA-3783) Race condition on last ACL removal for a resource fails with a ZkBadVersionException

["Sébastien Launay (JIRA)" <ji...@apache.org>]

Sébastien Launay created KAFKA-3783:
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             Summary: Race condition on last ACL removal for a resource fails with a ZkBadVersionException
                 Key: KAFKA-3783
                 URL: https://issues.apache.org/jira/browse/KAFKA-3783
             Project: Kafka
          Issue Type: Bug
    Affects Versions: 0.10.0.0, 0.9.0.1
            Reporter: Sébastien Launay
            Priority: Minor


When removing the last ACL for a given resource, the znode storing the ACLs will get removed.
The version number of the znode is used for optimistic locking in a loop to provide atomic changes across brokers.

Unfortunately the exception thrown when the operation fails because of a different version number is the wrong one ({{KeeperException.BadVersionException}} instead of ZkClient {{ZkBadVersionException}})  and does not get caught resulting in the following stack trace:
{noformat}
org.I0Itec.zkclient.exception.ZkBadVersionException: org.apache.zookeeper.KeeperException$BadVersionException: KeeperErrorCode = BadVersion for /kafka-acl/Topic/e6df8028-f268-408c-814e-d418e943b2fa
	at org.I0Itec.zkclient.exception.ZkException.create(ZkException.java:51)
	at org.I0Itec.zkclient.ZkClient.retryUntilConnected(ZkClient.java:1000)
	at org.I0Itec.zkclient.ZkClient.delete(ZkClient.java:1047)
	at kafka.utils.ZkUtils.conditionalDeletePath(ZkUtils.scala:522)
	at kafka.security.auth.SimpleAclAuthorizer.kafka$security$auth$SimpleAclAuthorizer$$updateResourceAcls(SimpleAclAuthorizer.scala:282)
	at kafka.security.auth.SimpleAclAuthorizer$$anonfun$removeAcls$1.apply$mcZ$sp(SimpleAclAuthorizer.scala:187)
	at kafka.security.auth.SimpleAclAuthorizer$$anonfun$removeAcls$1.apply(SimpleAclAuthorizer.scala:187)
	at kafka.security.auth.SimpleAclAuthorizer$$anonfun$removeAcls$1.apply(SimpleAclAuthorizer.scala:187)
	at kafka.utils.CoreUtils$.inLock(CoreUtils.scala:231)
	at kafka.utils.CoreUtils$.inWriteLock(CoreUtils.scala:239)
	at kafka.security.auth.SimpleAclAuthorizer.removeAcls(SimpleAclAuthorizer.scala:186)
	...
Caused by: org.apache.zookeeper.KeeperException$BadVersionException: KeeperErrorCode = BadVersion for /kafka-acl/Topic/e6df8028-f268-408c-814e-d418e943b2fa
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:115)
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
	at org.apache.zookeeper.ZooKeeper.delete(ZooKeeper.java:873)
	at org.I0Itec.zkclient.ZkConnection.delete(ZkConnection.java:109)
	at org.I0Itec.zkclient.ZkClient$11.call(ZkClient.java:1051)
	at org.I0Itec.zkclient.ZkClient.retryUntilConnected(ZkClient.java:990)
	... 18 more
{noformat}

I noticed this behaviour while working on another fix when running the {{SimpleAclAuthorizerTest}} unit tests but this can happens when running simultaneously the {{kafka-acls.sh}} command on different brokers in rare cases.



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