Let's say you have a completely separated instance (worker dyno on Heroku) for doing more resource-eating work like complicated calculations, processing data in the database, or exchanging a lot of data with an external service. You will want the "normal" instances (and therefore the users) to know the result of this work when it's done.

If you chose PaaS as hosting for your application, you probably had or will have this problem: Your app is deployed to small "containers" (known as dynos in Heroku, or gears in OpenShift) and you want to scale it. In order to do so, you increase the number of containers—and every instance of your app is pretty much running in another virtual machine. This is good for a number of reasons, but it also means that the instances don't share memory.

The simplest example will just send information to other instances that you've just started. For example, you can display this information in the admin panel. Before we do anything, create another connection named client2. I will explain why we need it later.Let's start by just sending the message that we started. It's done using the publish() method of the client. It takes two arguments: the channel we want to send the message to, and the message's text:

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