[KAFKA-278] Issues partitioning a new topic

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.7
• Component/s: core
• Assignee: Unassigned
• Reporter: Matt
• Created: 17/Feb/12 22:57
• Updated: 11/Jul/13 22:43
• Resolved: 11/Jul/13 22:43

Description

There are two cases where correct partitioning fails for a new topic.

Case 1: Topic exists on current Kafka cluster. A new broker is added to the cluster. The new broker will never host partitions for the existing topic.

To reproduce:
1) Create a cluster of brokers along with a ZooKeeper ensemble.
2) Send messages for a topic to the cluster.
3) Add a new broker to the cluster.
4) New broker will never see the existing topic.

Case 2: Topic does not exist on current Kafka cluster. Producer sends messages to a new topic that did not previously exist in the cluster. If, during the producer session, one or more partitions are not created on a broker, the broker will never host those partitions.

To reproduce:
1) Create a cluster of brokers along with a ZooKeeper ensemble.
2) Send messages to a new topic.
3) Shut down the producer before the topic is created on at least one broker.
4) The broker that did not allocate the topic will never host the topic.

My guess here is that when a new producer is created, it gets a list of topics and partitions based on the current state of the brokers in the cluster. Since some brokers are missing the topic, the producer will never send messages to that broker and partitions will never be created.

Work around:
Manually create the topic/partition directories in the kafka logs directory and reboot kafka. It will register the topic/partitions in ZooKeeper.