configure multiple server to support sidekiq

Question

I planned to migrate redis server to a new one with sidekiq running, but doesn't want to stop the current application running. And I don't want to use redis cluster which is still alpha version. My thought is to ask sidekiq to write to new redis server, but pulls from both of them, so that once the workers in old redis are completed, the new one can totally take over all workers. I think this solution is feasible, but I have no idea how to make it happen.

This is my sidekiq.rb:

sidkiq_config = YAML.load(ERB.new(Rails.root.join('config/redis.yml').read).result)

Sidekiq.configure_server do |config|
  config.logger.level = Logger::ERROR
  config.redis = { :url => "redis://redis2.staging:6379", :namespace => "app_#{Rails.env}:sidekiq" }
  config.redis = { :url => "redis://redis.staging:6379", :namespace => "app_#{Rails.env}:sidekiq" }
end

Sidekiq.configure_client do |config|
  config.logger.level = Logger::ERROR
  config.redis = { :url => "redis://redis2.staging:6379", :namespace => "app_#{Rails.env}:sidekiq" }
end

Answer 1

I believe the easiest solution is to run two instances of sidekiq - one that reads from the old cluster, and one that reads from the new cluster

sidkiq_config = YAML.load(ERB.new(Rails.root.join('config/redis.yml').read).result)

Sidekiq.configure_server do |config|
  config.logger.level = Logger::ERROR
  if ENV['read_from_new']
    config.redis = { :url => "redis://redis2.staging:6379", :namespace => "app_#{Rails.env}:sidekiq" }
  else 
    config.redis = { :url => "redis://redis.staging:6379", :namespace => "app_#{Rails.env}:sidekiq" }
  end
end

Sidekiq.configure_client do |config|
  config.logger.level = Logger::ERROR
  config.redis = { :url => "redis://redis2.staging:6379", :namespace => "app_#{Rails.env}:sidekiq" }
end