What kind of state can an instance have?

An instance or server can have different state depending on Amazon and Scalarium. In order of the typical lifecycle:

New The instance was just defined in Scalarium and never started. Amazon doesn't know anything about this instance. It is just a Scalarium internal representation of a server

Requested The user asked Scalarium to start the instance. Scalarium is internally scheduling an agent to call Amazon to actually start the instance

Pending Amazon acknowledged the request to start the instance. From this moment on you paying for the instance from both Amazon's and Scalarium's perspective.

Booting The instance is now alive on Amazon EC2. The instance is booting and completing the installation of the Scalarium agent. You can SSH into the instance but the setup process hasn't started yet.

Running Setup The instance agent successfully connected to Scalarium and got the configuration necessary to turn the blank Linux server into your custom instance. The instance is installing all dependencies and software told.

Online The instance completed the setup process and is now considered functional. Other instances in the cluster recognize the instance and will re-configure if necessary.

Setup Failed If something during the setup process (like you misspelled a Rubygem or a custom Chef recipe causes an error), the instance will not be marked as online but as 'setup failed'. You can now login and debug your problem. The instance will not be used or recognized by any other instance in the cluster.

Offline If Scalarium looses contact to an instance, it marks an instance as offline. Other instances in the cluster will re-configure themselves without the offline instance in their configuration.

Shutting Down The instance is shutting down on Amazon EC2

Stopped The instance is no longer running on EC2, you stopped paying for the instance on Amazon and on Scalarium. The Amazon instance is no recoverable. You can start this instance on Scalarium again but it will be a different Amazon instance.