Tuesday, November 29, 2011

Managed Clouds with RightScale

Having your head in the clouds and managing virtual machines (VMs) which run there is one thing, really getting there is another. An often neglected step in cloud discussions is the cloud on-ramp, or How does the VM providing the needed functionality get there in the first place? Also frequently ignored is the question of What's inside the VM? Maybe these questions are "ignored" as they are inconvenient and not necessarily easy to answer. Similar to driving a car on the highway - once on the highway going along with the flow of traffic is easy, but navigating the on-ramp poses a set of challenges that make many uncomfortable.

The on-ramp to the cloud can take various shapes. One is to pre-build task specific VMs (eg. a web server), which is easy with SUSE Studio and KIWI. If you have multiple functions that needs to be distributed between multiple instances, you can build one image each and then launch them in the cloud.

Another way to the cloud is to customize the VM on startup - start with a standard base image and then install the necessary packages and configuration on first boot. This is the approach taken by RightScale and we are happy to annouce that these base images are now available in SUSE Gallery, in both 32-bit and 64-bit flavours.

When launched from the RightScale interface, the base image/VM connects to the RightScale servers and pull in any scripts that need to be executed. All connections are outbound only, hence safe from a security perspective and does not require any additional ports or special access.

Here's a step-by-step guide on how to use it:
  1. Upload the RightScale base image (32-bit, 64-bit) to your EC2 account.
  2. Log into your RightScale account and create a "Multi Cloud Image" (MCI) based on the EC2 image.
    Important:
    Add the "provides:rs_agent_type=right_link" tag to the MCI during creation. 
  3. Create a "Server Template". The template may contain a script that installs the required packages and configuration. The following example shows the basic setup for a web server:


These RightScripts can be written in pretty much any scripting language, as long as it is installed in your base image. With a server template complete you can create a "Deployment" in RightScale. Launch your EC2 image from this deployment and the script in your server template will be automatically executed during boot up.

With RightScale, instead of managing multiple images you manage server templates and their content using the RightScale interface. Thus, on the surface you are just managing a different thing when compared to the approach discussed earlier. Once there are multiple clouds, RightScale does offer a reduced management surface. It is possible to reuse existing server templates and thus the setup of a web server, for example, in cloud A and cloud B does not require a new build once you have a base image in both clouds.

RightScale supports only enterprise Linux distributions. For details, please refer to their support page.

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