Bare-Metal PaaS

The Rise of Bare-Metal Clouds

Cloud and Virtualization are not mandatory, and the number of cloud providers that supports bare-metal clouds is growing, as David Linthicum pointed out in his article Going native: The move to bare-metal cloud services

It’s a fact that virtualization is not a requirement when creating cloud computing services, but it is helpful to those who manage the service. Indeed, Google is able to provide a multitenant cloud computing platform without virtualization; there are other examples as well.

Internap, SoftLayer, Rackspace, Liquid Web, and New Servers (also known as BareMetalCloud.com) also provide access to the bare metal. You can count on more providers to join the fray as cloud computing users continue to demand that their managed hosting environments work like their native environments.

Performance Matters

The main reason for the rise of bare-metal clouds is that virtualization often comes with a cost. There is a  large class of applications where the virtulization overhead is unacceptable, as Carl Brooks, a cloud analyst at Tier 1, a division of 451 Research, points out here:

By having dedicated servers that are not virtualized, and therefore do not have a hypervisor layer, users can experience an uptick in speed, Brooks says, in some cases as much as 10% depending on the application. This can be an attractive option for high-performance compute needs, advanced Web 2.0 developers, or applications that require a large amount of database resources. Basically any situation “where the performance matters the most”

Come to think of it, the main thing that brought us to virtualization in the first place was the ability to create new servers on demand, as opposed to it taking days or weeks with dedicated servers. Now, with the avliability of bare-metal clouds, it is possible to get the same level of flexibility without the virtualization overhead, and with more control and flexibiltiy on the specific HW configuration and setup. This makes the choice of bare-metal clouds much more attractive than in the past.

Bare-Metal PaaS

Now that bare-metal clouds have become more popular, it only makes sense to have bare-metal PaaS to support them. Bare-metal PaaS provides the abilty to manage an elastic application workload without relaying on virtualization, providing the option to support high-performance workloads with the simplicity of PaaS.
This is particularly interesting for Big Data and any data intensive application that is heavy on I/O. Quite often, running these types of applications on top of virtualization isn’t even considered a viable option. With bare-metal PaaS we can easily serve I/O intensive workload without compromising on performance or latency.

A Bare-Metal PaaS Example with Cloudify

Cloudify is an open PaaS stack. With Cloudify, we look at cloud infrastructure as just a bunch of compute resources with an operating system, IP address, SSH port. We use a generic Cloud-Driver that enables us to abstract the way those machines can be allocated and created on each different clouds infrastructure. In that context we treat a virtual machine as just generic container of an operating system. Cloudify manages applications at the process level. This means it manages the application workload by provisioning the application processes across machines.

With that, it only made sense to look at bare-metal clouds as any other virtualized cloud. So we ended up writing a bare-metal cloud driver, which is referred to as the Bring Your Own Node (BYON) cloud driver.
A BYON cloud is set simply by specifying a list or range of IP addresses as our cloud pool. Cloudify then uses this pool to provision the application and its services. Below is a simple example that shows what this configuration looks like.

templates ([
SMALL_LINUX : template{
custom ([
“nodesList” : ([
([
“id” : “vm1”,
“ip” : “10.10.10.1”
]),
([
“id” : “vm2”,
“ip” : “10.10.10.2”
]),
([
“id” : “vm3”,
“ip” : “10.10.10.3”
])
])
])
}
])
A list of more advanced configuration options is available here.

Keeping Available the Choice Between Bare-Metal and Virtualized Cloud 

In reality, there are cases where the use of virtualized cloud instances makes sense, and as already discussed here, there are also cases where using a bare-metal cloud would be the right option. Ideally it would be best to abstract the application from those choices in order to easily move between the two environments, or even combine them. For example, imagine the case of a typical web application. It is very likely that we would want to run our web traffic workload on virtualized instances and our database on bare-metal instances.
In the case of Cloudify — keeping the details of the specific cloud target at the CloudDriver enables us to achieve just that. We can define our application as a recipe, which is kept unchanged between the cloud choices. The details of whether to use a bare-metal or virtualized cloud is left to the deployment stage where all that is needed is to point Cloudify to the target cloud driver, and that’s it.

References

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