About images and instances

Atmosphere provides a number of images from which you can launch an instance.

• An image is a template for an instance that exists on a virtual machine (VM). Images contain the installed operating system, software, and configuration that is required for use with that setup.
  
• An instance, in the Atmosphere world, is a VM image that has been launched. Each instance is a specific VM that exists on a physical compute node, with its own dedicated RAM, CPUs, and disk space.

For the list of images and the tools used in each image, see List of Atmosphere Images.

You use an instance in Atmosphere just as you use a physical computer for most tasks. Once you have selected the image to use, you launch an instance of the image.

For more information on virtual machines, see Virtual machines on the Wikipedia website. For a general overview of cloud computing, see Cloud Computing Explained on the Webopedia website.

About instance size

An important consideration is the size of the instance. Instance size determines the amount of resources (CPUs, RAM, Atmosphere Units, or a combination of the three) that will be used when you launch the instance.

The provider you select determines the amount of resources and options that are available. Atmosphere offers two different cloud provider types.

All new and existing users will have a 336 AUs starter allocation, enough time to continuously run a 1 CPU-core instance for 1 week. Users who exceed their allocation will have their instances suspended until their allocation is refreshed. Additional allocation can be obtained using the 'Request more resources' form within Atmosphere, which will be reviewed by an allocation committee.

Your resource usage is determined by the cumulative amount of CPUs, RAM, and Atmosphere Units (AUs), or a combination of the three. One AU is roughly equivalent to one CPU-hour, or one CPU-core used per hour. For example, a 16-core instance running for one hour uses 16 AUs. You may request more resources within Atmosphere. If your resource usage bars indicate you are already using 100% of your resources, you must either select a smaller instance size or a different instance, terminate or suspend a different running instance, or request more resources.

Instance size is set by default to the smallest amount available in each provider, and this is sufficient for most uses. A larger size gives you more computing power but fewer remaining resources for other running instances, while a smaller size gives you more resources to launch more instances but less computing power.

The size you select determines how much of your resource allocation you use, as well as how much power is available to you for the instance; both are displayed in the My Projected Resource Usage section above the instance information section.

Instances are available on a first-come-first-served basis. Depending on Atmosphere's capacity, you may be unable to launch an instance even though you have sufficient allocation. However, be aware that your time allocation is reset at the beginning of the month to the default 336 AUs. As always, you may request more AUs as needed.

An instance that has not performed significant computations measured by load average or which has not had an interactive session via SSH or VNC for more than three (3) calendar days may be suspended by Atmosphere Support and then resumed, depending on available resources, at a later time.

For more information on virtual machines, see Virtual machine on the Wikipedia website.
For a general overview of cloud computing, see Cloud Computing Explained on the Webopedia website.

Using the Instances Actions menu

To open the Images window, click Images at the top. The Actions menu is displayed when an instance name is clicked to open. The state of the instance determines which Actions menu items are displayed or enabled.

Trying to resize an image?

The ability to resize an instance has been disabled until a future release.