When/how does a topic "marked for deletion" get finally removed?

tl;dr Set delete.topic.enable = true in config/server.properties of Kafka brokers and...be patient.

It happens with the latest development version of Kafka 0.8.3-SNAPSHOT:

➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗ ./bin/kafka-topics.sh --zookeeper localhost:2181 --create --topic my-topic --partitions 2 --replication-factor 1
Created topic "my-topic".

➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗ ./bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic my-topic
Topic:my-topic  PartitionCount:2    ReplicationFactor:1 Configs:
    Topic: my-topic Partition: 0    Leader: 0   Replicas: 0 Isr: 0
    Topic: my-topic Partition: 1    Leader: 0   Replicas: 0 Isr: 0

➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗ ./bin/kafka-topics.sh --zookeeper localhost:2181 --delete --topic my-topic
Topic my-topic is marked for deletion.
Note: This will have no impact if delete.topic.enable is not set to true.

➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗ ./bin/kafka-topics.sh --zookeeper localhost:2181 --list
➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗

The point is to have delete.topic.enable=true in config/server.properties that you use to start a Kafka broker.

➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗ grep delete.topic.enable config/server.properties
delete.topic.enable=true

You can also ensure the setting be true in a broker's log:

➜  kafka_2.11-0.8.3-SNAPSHOT git:(trunk) ✗ ./bin/kafka-server-start.sh config/server.properties
[2015-07-24 22:33:26,184] INFO KafkaConfig values:
        ...
        delete.topic.enable = true

You can do it.

sudo ./zookeeper-shell.sh localhost:2181 rmr /brokers/topics/your_topic

I faced the same issue and spend a couple of days trying to identify with the issue was. I triggered command to delete the topics, however the topics were marked for deletion but they were not deleted.

1. I first checked the configuration which are set right. Under: server.properties

   delete.topic.enable=true for all brokers

2. I restarted the broker to check if the topics got delete (No!!).
3. I check no data under /kafka/data folder.
4. I even considered the option to wait until the retention time got exceed.

None helped. I had to finally login to zooker

./zkCli.sh # and delete the topics using 
rmr /brokers/topics/<<topic>> and rmr /admin/delete_topics/<<topic>>

Please remember to restart kafka after this. Hope this solves your issue.

In my case where i am using Kafka 8.2.2, I had to delete entries from the following manually -

1. Delete topic folder from Kafka broker machine.

2. Login to zookeeper and -

   hbase zkcli
   rmr /brokers/topics/{topic_name}
   rmr /admin/delete_topics/{topic_name}