Some projects require integration tests to be written against running instances of Couchbase, which in turn requires environment setup & teardown as is typical with most integration tests. This plugin facilitates this by providing goals to create and delete buckets which can then be used for testing.
No. Couchbase Server does not currently (v1.8) provide a simple mechanism to start / stop an instance with custom configuration (e.g. a specific port). This means that parallel builds might step on each others' toes if they're starting / stopping the same instance of Couchbase Server. A safer approach is to provide 'sandbox' buckets for each build, which is facilitated via the create-bucket and delete-bucket goals.