kafka cookbook

Installs Kafka v0.8.1.1, and probably any newer versions.

Based on the Kafka cookbook released by WebTrends (thanks!), but with a few notable differences:

• does not depend on runit cookbook.
• does not depend on zookeeper cookbook, thus it will not search for nodes with a specific role or such, that is left up to you to decide.
• only tested on Vagrant boxes.
• intended to be used by wrapper cookbooks.

Requirements

This cookbook does not depend on any specific cookbooks, but it requires that java is installed on the system, thus the java cookbook is recommended.

Ruby 1.9.3+ and Chef 11.6.0+.

Platform

• Amazon Linux
• CentOS 6.5 and 7
• Debian 7.4
• Fedora 20
• Ubuntu 14.04

Might work on other platforms / versions, but these are the ones that are included in .kitchen.yml and/or tested in the wild, so YMMV.

Attributes

In order to keep the README in some kind of manageable state (and thus in sync with attributes), attributes are documented inline (in the attribute files that is).

Attributes concerning configuring of a Kafka broker are to be set under the broker namespace, and one can choose which ever syntax they prefer the most, the following are all valid ways to define broker configuration:

node.default.kafka.broker[:log_dirs] = %w[/tmp/kafka-logs]
node.default.kafka.broker['log.dirs'] = %w[/tmp/kafka-logs]
node.default.kafka.broker.log.dirs = %w[/tmp/kafka-logs]
node.default[:kafka][:broker][:log][:dirs] = %w[/tmp/kafka-logs]

A warning regarding the "dotted" notation, it doesn't play very well when setting attributes like default.replication.factor or fetch.purgatory.purge.interval.requests due to fairly obvious reasons (default and fetch are also methods).

Refer to the official documentation for the version of Kafka that you're installing. Documentation for the latest release can be found over here.

Recipes

This section describes the different recipes that are available.

default

Downloads and installs Kafka from the official binary releases. Defaults to installing v0.8.1.1 of Kafka.

Controlling restart of Kafka brokers in a cluster

Any changes made to the broker configuration could result in a restart of the Kafka broker, depending on configuration of this cookbook. If Chef runs as a daemon on all of the nodes this could result in all of the Kafka brokers being brought down at the same time, resulting in unavailability of service.

If unavailability is an issue, this cookbook provides an option to implement custom logic to control the restart of Kafka brokers so that not all of the brokers in a cluster are stopped at the same time. For example the custom logic can be something along the lines of acquiring a lock in ZooKeeper and when held the broker is allowed to restart. Be aware that a restart might take quite some time if you're using controlled shutdown and have a lot of partitions, and Chef usually have some timeout for each resource.

By default the resources in the _coordinate recipe performs the start/restart of the kafka service. If custom logic needs to be implemented, this recipe can be replaced with another recipe, but don't forget to update the kafka.start_coordination.recipe attribute.

The only requrirement is that the new recipe has a ruby_block resource with 'coordinate-kafka-start' as ID. The following is a sample recipe that shows roughly what one can do with this feature.

ruby_block 'coordinate-kafka-start' do
  block do
    Chef::Log.info 'Custom recipe to coordinate Kafka start/restart'
  end
  action :create
  notifies :create, 'ruby_block[restart-coordination]', :delayed
end

ruby_block 'restart-coordination' do
  block do
    Chef::Log.info 'Implement the process to coordinate the restart, like using ZK'
  end
  action :nothing
  notifies :restart, 'service[kafka]', :delayed
  notifies :create, 'ruby_block[restart-coordination-cleanup]', :delayed
end

service 'kafka' do
  provider kafka_init_opts[:provider]
  supports start: true, stop: true, restart: true, status: true
  action kafka_service_actions
end

ruby_block 'restart-coordination-cleanup' do
  block do
    Chef::Log.info 'Implement any cleanup logic required after restart like releasing locks'
  end
  action :nothing
end

Please refer to issue #58 for background of this feature.

Copyright

Copyright :: 2013-2014 Mathias Söderberg and contributors

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Contributing

1. Fork the repository on Github
2. Create a named feature branch (like add-component-x)
3. Write your change
4. Check that your change works, for example with Vagrant
5. Submit a Pull Request using Github