Setting log.dirs outside of Mesos executor workspace is tedious

[plaflamme]

To store Kafka's topic data outside of Mesos' executor workspace, we can use the log.dirs property and specify an absolute path to the system, e.g.: /mnt/array1/kafka,/mnt/array2/kafka.

This works fine, but will break when 2 different brokers run from the same Mesos agent. When a broker starts, it creates a meta.properties file in each log.dirs directory which contains the broker id. So if a new broker with a different id is started on that agent, it refuses to start.

This situation can happen for 2 reasons:

• the broker configuration is not using constraints and the scheduler ends up using the same agent
• a broker used to run on that agent, but no longer does (so even with constraints on, we can get in this situation)

The solution is to use a slightly different log.dirs parameter per broker (e.g.: /mnt/array1/kafka/broker0) but that's tedious since you have to specify a different configuration for each broker.

It would be nice if one could specify a path that kafka-mesos would manage or allow substitution, (e.g.: /mnt/array1/kafka/broker${brokerId})

Probably using Mesos' persistent volumes can also solve this, but it's not clear to me how this feature works with kafka-mesos.

[joestein]

you can use $id to-do what you are looking for e.g. https://github.com/mesos/kafka#rolling-restart

[plaflamme]

Argh! Didn't notice that in the examples. Thanks!