Compute Engine is currently in preview phase; Google is accepting limited access for new accounts. Today, you can create a Linux VM consisting of one, two, four or eight cores each, with 3.75 Gbytes of RAM per core. The VMs are either Ubuntu 12.04 or CentOS 6.2, 64-bit Linux OSes. The networking options are thin as well, with what looks like Layer 3 networking, only with the ability to have a static or ephemeral public IP address and a firewall to set access control.
There are a number of options for storage. Each VM can have an ephemeral disk for temporary storage while it's running and the data written to it is encrypted. Once the VM stops, the ephemeral disk is destroyed. Persistent disks, also encrypted, can be attached to one or more VMs (though disks attached to more than one VM are read-only), and Google promises the same read and write performance of a local disk. Additionally, Google Compute Engine (GCE) VMs can access Google Cloud Storage.
"The GCE options seem to be a very random set of variables and one which might have flown five years ago," says Ben Kepes, an analyst at Diversity Analysis. "But my belief is that cloud customers have moved on and want far more flexibility and maturity in a platform."
The initial version of Google Compute Engine won't take share from other IaaS providers in the cloud computing space like Amazon, Microsoft or Rackspace, which offer a wider variety of configurations that can support OSes that require more capacity like Windows Server.
Google's own developer documentation states, "Compute Engine is designed to run high-performance, computationally intensive virtual compute clusters in the Google Cloud," which is clearly evident by the choice and configuration of the initial offerings for virtual machines and storage. The documentation also indicates GCE can be used in conjunction with Google's PaaS offering, App Engine. For example, App Engine could hold the user-facing components while Compute Engine performs computationally expensive operations like media rendering.
Next: Challenges Facing Google Compute Engine