title: Periodic Jobs not registered in Sidekiq
body: <p>I have sidkiq configured as following.</p>
  <pre><code># config/initializers/sidekiq.rb
  
  require 'sidekiq/web'
  Sidekiq::Web.use(Rack::Protection, origin_whitelist: ['https://mysite'])
  
  redis_config = { url: ENV['SIDEKIQ_REDIS_URL'] }
  
  Sidekiq.configure_server do |config|
    config.redis = redis_config
    config.average_scheduled_poll_interval = 1
    config.periodic do |mgr|
      mgr.register('* 2 * * *', 'MyPeriodicWorker') # 2am daily
    end
  end
  
  Sidekiq.configure_client do |config|
    config.redis = redis_config
  end
  </code></pre>
  <p>After I built docker image locally, I ran it from my laptop and it did work.</p>
  <pre><code>[Patch] Preventing bunny channel leak
  2020-11-26T09:01:45.452Z pid=1 tid=gq3ufhkop INFO: Booting Sidekiq 6.0.7 with redis options 
  {:url=&gt;&quot;redis://127.0.0.1:56379/4&quot;}
  2020-11-26T09:01:46.705Z pid=1 tid=gq3ufhkop INFO: Booted Rails 6.0.3.1 application in 
  staging environment
  2020-11-26T09:01:46.705Z pid=1 tid=gq3ufhkop INFO: Running in ruby 2.6.5p114 (2019-10-01 
  revision 67812) [x86_64-linux-musl]
  2020-11-26T09:01:46.705Z pid=1 tid=gq3ufhkop INFO: Sidekiq Pro 5.0.1 / Sidekiq Enterprise 
  2.0.1, commercially licensed.
  2020-11-26T09:01:46.721Z pid=1 tid=gq3v7vxkt INFO: Managing 1 periodic jobs
  2020-11-26T09:01:46.724Z pid=1 tid=gq3v7vxkt INFO: Gained leadership of the cluster
  </code></pre>
  <p>But when I deployed it to k8s cluster, it didn't.</p>
  <pre><code>[Patch] Preventing bunny channel leak
  2020-11-26T08:17:01.324Z pid=1 tid=gtmxb31mt INFO: Booting Sidekiq 6.0.7 with redis options 
  {:url=&gt;&quot;redis://:REDACTED@myredisinstance:6379/4&quot;}
  2020-11-26T08:17:02.406Z pid=1 tid=gtmxb31mt INFO: Booted Rails 6.0.3.1 application in 
  staging environment
  2020-11-26T08:17:02.406Z pid=1 tid=gtmxb31mt INFO: Running in ruby 2.6.5p114 (2019-10-01 
  revision 67812) [x86_64-linux-musl]
  2020-11-26T08:17:02.406Z pid=1 tid=gtmxb31mt INFO: Sidekiq Pro 5.0.1 / Sidekiq Enterprise 
  2.0.1, commercially licensed.
  </code></pre>
  <p>What makes the difference?</p>