Initial release features support for Zookeeper

[silkentrance]

As a test developer I need to have a working Zookeeper instance. While I do not need direct access to that instance, it must be available for integration of other Hadoop components.

I want to be able to configure the Zookeeper instance by means of annotating the test class.

When running tests in parallel, I want the system to not start multiple Zookeeper instances for a specific test class or a suite of test classes that derive from a common super class which provides the Zookeeper configuration. Instead, all of these threads must share the same instance. In effect, there is only one Zookeeper instance that is shared across all threads.

Other components, such as Kafka, HBase and possibly others need to be configured based on the effective Zookeeper configuration for a given thread.

Running the same tests on the same system from multiple processes must not lead to failing tests. Individual instances of Zookeeper must have their own ports. The ports must be determined automatically.

Acceptance criteria

• Zookeeper is provided
• Zookeeper instances can be configured via annotation on ElementType.TYPE level
• There is only one Zookeeper instance that is shared across multiple threads
• The effective Zookeeper instance configuration is used for configuring other provided components
• Zookeeper instances use dedicated free ports that have been determined automatically