NOTE: The documentation below refers to an unreleased version of kuby-redis. Please click here for the documentation for the currently released version.

kuby-redis

Redis plugin for Kuby. If you're looking for an easy way to add Sidekiq to your app, check out kuby-sidekiq.

Intro

The redis plugin provides the ability to stand up arbitrary redis instances. Behind the scenes it uses the excellent Spotahome Redis operator.

Configuration

Add the kuby-redis gem to your Gemfile and run the setup command, eg:

bundle exec kuby -e production setup

Add a Redis instance like this:

require 'kuby/redis'

Kuby.define(:production) do
  kubernetes do

    add_plugin(:redis) do
      instance(:my_rails_cache)
    end

  end
end

The kuby-redis plugin supports a number of additional configuration options:

• cpu_request, (default: '100m'). The number of CPU units to request from Kubernetes. 1 CPU core = 1000 units.
• memory_request, (default: '100Mi'). The amount of memory to request from Kubernetes.
• cpu_limit, (default: '400m'). A limit on the number of CPU units the Redis instance may consume. 1 CPU core = 1000 units.
• memory_limit, (default: '500Mi'). A limit on the amount of memory the Redis instance may consume.
• sentinel_replicas (default: 1). The number of Redis sentinels to run.
• redis_replicas (default: 1). The number of replicated Redis servers to run. For a highly-available configuration, set this option to a value >= 3.
• storage_access_modes, (default: ['ReadWriteOnce']). An array of Kubernetes storage access modes for the persistent volume that the Redis instance will use to persist data.
• storage, (default: '1Gi'). The amount of persistent storage to request. Note that this is not a Redis memory limit, but rather a request for an amount of persistent (i.e. disk-based) storage Redis will write to. Persistent storage is necessary to prevent data loss if/when an individual Redis instance fails.

NOTE: All memory amounts must be strings parseable by Go's go-units module. Valid examples include '100Mi' (100 megabytes) and '2Gi' (2 gigabytes).

Example:

Kuby.define(:production) do
  kubernetes do

    add_plugin(:redis) do
      instance(:my_rails_cache) do
        # Launch three redis replicas (this is the recommended configuration
        # for high availability).
        redis_replicas 3

        # The amount of persistent storage to request.
        storage '5Gi'
      end
    end

  end
end

Usage

Redis instances defined in your Kuby config respond to the #service_name, #service_port, and #connection_params methods to facilitate connecting to them from your Rails app. One caveat is that clients must be sentinel-aware, but for the most part users won't have to worry about this since the redis-rb gem supports sentinel configurations.

Rails Cache

In your Rails config (eg. config/environments/production.rb), point your cache store at your redis instance like so:

# make sure Kuby config is loaded
Kuby.load!

redis_instance = Kuby.environment.kubernetes
  .plugin(:redis)
  .instance(:my_rails_cache)

config.cache_store = :redis_cache_store, redis_instance.connection_params

Redis Gem

You can also use the redis-rb gem directly:

# make sure Kuby config is loaded
Kuby.load!

require 'redis'

redis_instance = Kuby.environment.kubernetes
  .plugin(:redis)
  .instance(:my_rails_cache)

redis = Redis.new(**redis_instance.connection_params)

License

Licensed under the MIT license. See LICENSE for details.

Authors

• Cameron C. Dutro: http://github.com/camertron