Failed to install Kafka on DCOS

Question

Installing Kafka on DCOS without any custom configuration gives the following logs

Cluster Configuration:

8 Private Nodes, 2 Open Nodes

24 Cores Total, 320 GB Ram Total

All resources are free.

StdErr output:

log4j:WARN No appenders could be found for logger (org.jboss.logging).  
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.NullPointerException
at com.mesosphere.dcos.kafka.plan.KafkaUpdateBlock.initializeStatus(KafkaUpdateBlock.java:196)
at com.mesosphere.dcos.kafka.plan.KafkaUpdateBlock.<init>(KafkaUpdateBlock.java:50)
at com.mesosphere.dcos.kafka.plan.KafkaUpdatePhase.createBlocks(KafkaUpdatePhase.java:83)
at com.mesosphere.dcos.kafka.plan.KafkaUpdatePhase.<init>(KafkaUpdatePhase.java:27)
at com.mesosphere.dcos.kafka.scheduler.KafkaScheduler.<init>(KafkaScheduler.java:125)
at com.mesosphere.dcos.kafka.scheduler.Main.run(Main.java:70)
at com.mesosphere.dcos.kafka.scheduler.Main.run(Main.java:21)
at io.dropwizard.cli.EnvironmentCommand.run(EnvironmentCommand.java:40)
at io.dropwizard.cli.ConfiguredCommand.run(ConfiguredCommand.java:77)
at io.dropwizard.cli.Cli.run(Cli.java:70)
at io.dropwizard.Application.run(Application.java:80)
at com.mesosphere.dcos.kafka.scheduler.Main.main(Main.java:27)

Stdout Output:

ERROR com.mesosphere.dcos.kafka.scheduler.KafkaScheduler: Got 1 errors from new config. Falling back to last valid config.
INFO com.mesosphere.dcos.kafka.plan.KafkaUpdateBlock: Setting initial status for: broker-0
INFO com.mesosphere.dcos.kafka.plan.KafkaUpdateBlock: TargetConfigName: 67004a73-e9a0-4bf6-8e01-9eb52a674c1a currentConfigName: null
Command exited with status 1 (pid: 10171)

Answer 1

The problem is fixed by following the instructions here: https://docs.mesosphere.com/1.8/usage/service-guides/kafka/uninstall

To re-install the Kafka package, we first need to clear its previous state from Zookeeper. It simply will not work to remove it from the GUI or CLI, after uninstalling, clear the previous state from zookeeper and then update.