Before you start launching instances in the cloud using the RightScale platform, it's important to first understand how a server is defined, launched, and configured using RightScale's ServerTemplate model. A proper understanding of how instances are launched in the cloud will provide you with a useful perspective as you become more familiar with the RightScale platform and start launching your own custom servers.
When you launch a Server from the RightScale platform (Dashboard or API), the following actions take place to properly configure your instance in the cloud.
Note: The example below applies to how EC2 instances are defined, launched, and configured in AWS using RightScale's ServerTemplate model.
Define a Server
Before you can launch a Server, you must first define how that Server will be configured. For example, you need to choose an operating system (CentOS 5.4, Ubuntu, 9.10, Windows 2008, etc.), the desired size or hardware specifications for the cloud instance, as well as into which cloud or AWS region the instance will be launched.
- Go to the RightScale Component Library (Design > MultiCloud Marketplace > ServerTemplates) to find a ServerTemplate that best satisfies your server requirements. Import a copy of the ServerTemplate into your local collection (Design > ServerTemplates). You can either use the ServerTemplate as-is or clone it to create an editable version that you can customize yourself. You can also create your own ServerTemplate from scratch.
- Use the ServerTemplate to add a Server to a Deployment or configure a Server Array. You will also need to provide any required cloud-specific information. Below is a list of the minimum requirements that must be specified in order to launch an EC2 instance.
- AWS Region - Select into which AWS Region the instance will be launched. (e.g. AWS US-East)
- EC2 instance type - Defines the hardware specifications of the provisioned instance. (e.g. m1.small, m1.large, etc.)
- Amazon Machine Image (AMI) - The base machine image that will be loaded onto the instance by Amazon. The selection of the appropriate AMI (based upon the selected AWS Region) will be chosen by the ServerTemplate's MultiCloud Image (MCI). (e.g. RightImage_CentOS_5.4_i386_v5.6)
- EC2 SSH Key - Key pair used to establish SSH access to the instance.
- EC2 Security Group - Hardware firewall for controlling ingress communication to the instance.
- EC2 Elastic IP (optional) - Remappable Public IP address for use in EC2. Instead of being randomly assigned a Public IP by Amazon, you can choose to use an EIP that you've reserved for use within your AWS account.
Launch a Server
A Server can be launched from either the RightScale Dashboard (GUI) or API. You can either launch a Server manually or set up a scalable Server Array for autoscaling purposes that will grow/shrink (i.e. launch/terminate instances) depending on the various scaling parameters that you've defined.
- A Server is either manually or automatically launched.
RightScale makes an API request to the cloud provider on your behalf (using your cloud credentials) to launch a new instance. An instance will be provisioned to you based upon how you defined the Server above. For example:
- AWS Region: AWS US-East
- EC2 Instance Type: m1.small
- The cloud provider will use the following user-specified cloud resources to properly configure the bare instance. Each of these resources are AWS region-specific. The appropriate machine image will be chosen by the selected MultiCloud Image (MCI). (Note: A ServerTemplate can have more than one MCI.)
- Amazon Machine Image (AMI): (e.g. RightImage_CentOS_5.4_i386_v5.6)
- Kernel Image
- Ramdisk Image
- EC2 User Data
- EC2 SSH Key
- EC2 Security Group
- The cloud provider assigns the instance the following configurations. At the end of this phase, AWS declares the configured instance both active and billable.
- UID (unique identifier) (e.g. i-a97984c3)
- Private DNS Name
- Public DNS Name
- Private IP Address
- Public IP Address / Elastic IP (optional)
- RightScale associates the following RightScale-specific configurations with the instance:
- Sketchy host - Each instance will be assigned to one of RightScale's Sketchy servers, which monitors all server activity, alerts, and server status. The Sketchy servers collect Server data and draw the real-time monitoring graphs in the Dashboard.
- RightScale executes the list of enabled Boot Scripts that are defined by the Server's ServerTemplate in sequential order.
- If all scripts were executed successfully, RightScale will label it as an "operational" server.