The “disk” configuration value is denominated in MB. We recommend you set the configuration value
log_retention_bytes to a value smaller than the indicated “disk” configuration. See the Configuring section for instructions for customizing these values.
Managing Configurations Outside of the Service
The Kafka service’s core responsibility is to deploy and maintain the deployment of a Kafka cluster whose configuration has been specified. In order to do this the service makes the assumption that it has ownership of broker configuration. If an end-user makes modifications to individual brokers through out-of-band configuration operations, the service will almost certainly override those modifications at a later time. If a broker crashes, it will be restarted with the configuration known to the scheduler, not one modified out-of-band. If a configuration update is initiated, all out-of-band modifications will be overwritten during the rolling update.
The number of deployable brokers is constrained by two factors. First, brokers have specified required resources, so brokers may not be placed if the DC/OS cluster lacks the requisite resources. Second, the specified “PLACEMENT_STRATEGY” environment variable may affect how many brokers can be created in a Kafka cluster. By default the value is “ANY,” so brokers are placed anywhere and are only constrained by the resources of the cluster. A second option is “NODE.” In this case only one broker may be placed on a given DC/OS agent.
The security features introduced in Apache Kafka 0.9 are not supported at this time.