Cloud Servers Concepts

To use Cloud Servers service with or without the Cloud Networks extension, you should understand these key concepts:

Server

A virtual machine (VM) instance running on a host. To create a server, you must specify a name, flavor reference, and image reference.

Host

A physical server running multiple VM instances.

Flavor

A resource configuration for a server. Each flavor is a unique combination of disk space, memory capacity, vCPUs, and network bandwidth. See Flavors.

Image

A collection of files for a specific operating system (OS) that you use to create or rebuild a server. Rackspace provides pre-built images. You can also create custom images from servers that you have launched. Custom images can be used for data backups or as “gold” images for additional servers.

Reboot

This action performs either a soft or hard reboot of a server. A soft reboot is a graceful shutdown and restart of the operating system on your server. A hard reboot power cycles your server, which performs an immediate shutdown and restart.

Rebuild

This action removes all data on the server and replaces it with the specified image. Server ID and IP addresses on the server remain the same.

Resize

This action converts an existing server to a different flavor, which scales the server up or down. The original server is saved for a period of time to allow rollback if a problem occurs. You can confirm or revert a resize. A confirmed resize removes the original server. A reverted resize restores the original server. All resizes are automatically confirmed after 24 hours if you do not explicitly confirm or revert them.

CIDR

Classless Inter-Domain Routing (CIDR). A method for allocating IP addresses and routing Internet Protocol packets. When you create an isolated network through Cloud Networks, you specify a CIDR.

isolated network

A virtual Layer 2 network that your create through Cloud Networks and that you can attach to a new Cloud Server. Use an isolated network to keep your server separate from the Rackspace network, the Internet, or both. When you create a isolated network, it is associated with your tenant ID.

PublicNet

Provides access to the Internet, Rackspace services such as Cloud Monitoring, Managed Operations Service Level, RackConnect, Cloud Backup, and certain operating system updates. When you list networks through Cloud Networks, PublicNet is labeled public.

ServiceNet

An internal-only, multi-tenant network connection within each Rackspace data center. Provides access to Rackspace services, such as Cloud Files, Cloud Databases, Cloud Backup, and to certain packages and patches. ServiceNet IPs are not accessible from the Internet and are local to each data center. You can configure your account resources to use a ServiceNet IP address so that traffic over the internal network is not billed. When you list networks through Cloud Networks, ServiceNet is labeled as private.

How Cloud Servers work

Whether you choose to create a server by using the Cloud Control Panel, cURL, or the nova client, the basic steps are the same.

1. Select a region for your Cloud Server

   Tip

   To help you decide which regionalized endpoint to use, see special considerations.

2. Select your operating system

   Choose from a variety of popular Linux® or Windows distributions. The operating system for a server is known as its image.

3. Select a flavor for your Cloud Server

   Cloud Server flavors are a combination of RAM, disk space, disk I/O, vCPUs, and network throughput. For more information on flavors, see Flavors.

4. Your server is online in just a few minutes

   By using either the Cloud Control Panel or the API, you can upgrade or remove your Cloud Servers as your needs change.