Demystifying JeOS: The Evolution of the OS for Virtualization and Cloud
By Jake Sorofman, VP Marketing, rPath
Virtualization and cloud computing are forcing an evolution in the general-purpose operating system, from a one-size-fits-all approach optimized for the
server distribution channel to a streamlined approach optimized for
distribution with the application inside a virtual machine. In
virtualized computing environments, the OS has split, forming two
discrete systems -- a hypervisor for managing the physical
infrastructure and an application delivery system for managing the
application within the virtual machines.
The first discrete system, the hypervisor, provides hardware-based services. The
hypervisor is relatively well known because of high-profile hypervisor
vendors like Citrix, VMware, and most recently, Microsoft. The
hypervisor has enabled organizations to carve up server capacity and
realize far better utilization from hardware infrastructure, reducing
both capital and operating expenses for the datacenter.
The second discrete system binds to the application itself and takes
responsibility for all of the application-based services. Known
commonly as just enough operating system (JeOS), this approach is the
yin to the hypervisor's yang -- and it's a fundamental enabler of
application virtualization. JeOS (pronounced "juice") plays a pivotal
role in maximizing the portability, cost control, security and
manageability of applications in virtualized and cloud-based
The Gist of JeOS
At its most basic level, JeOS is an operating system streamlined to meet
the precise needs of a specific application. That means JeOS contains
only the pieces of the operating system and related system software
that a specific application needs to run.
In broad terms, this approach involves five steps:
the general purpose OS, storing the individual components in a
Inspect the application and specify the
requirements and policies for its run time and management dependencies;
the system software from the OS repositories around the application
based upon the requirements and policies determined in the previous
step. This creates the universal manifest for the maintenance and
management of the application.
Write the software
manifest determined in the previous step into the Virtual Machine
format required by your preferred hypervisor environment. Ideally, this
step is automated with each VM format defined as a target within your
release management system.
Easily deploy the
application without any of the manual set up, configuration and tuning
typically associated with the process of installing applications on a
physical server host.
JeOS turns the general-purpose operating system into a buffet of sorts. Take
what you need and leave the rest. This approach has several advantages:
Faster time to market. JeOS binds to the application instead of the
hardware infrastructure, creating a self-contained image that can run
on any virtualized infrastructure with minimal manual setup, tuning,
configuration or certification. JeOS frees applications from the
constraints and manual configuration of hardware infrastructure,
allowing them to be deployed instantly.
Lower maintenance, better security. JeOS eliminates unnecessary
operating system and middleware components, which can reduce the system
software footprint by 90 percent or more. Fewer components mean fewer
patches and updates, making the lifecycle management and maintenance of
deployed applications less complex and expensive. Likewise, operational
risks associated with security breaches are reduced.
portability. When constructed correctly, applications using
this method can be deployed on top of any hypervisor or in any cloud
environment, making them fundamentally portable. Applications initially
deployed on an internal cloud can be immediately redeployed in Amazon's
Elastic Compute Cloud (Amazon EC2) -- or in a cloud provided by
RackSpace, Terremark, GoGrid or a number of other providers. This
extreme portability takes business agility to a new level, opening the
door to the dynamic properties of cloud computing where application
workload can be shifted from cloud to cloud to take advantage of
comparative advantages in cost, performance or service availability.
here's the reality check: packaging and deploying applications in this
manner takes the friction out of application deployment, this will
lead to explosive growth in the volume of application images that need
to be managed and maintained. This means that organizations must be
prepared to deal with unforeseen levels of scale and complexity to
avoid being overwhelmed by virtual machine sprawl, application quality
issues, compounding maintenance costs, rogue applications "leaking"
into the cloud, and the risk of getting locked into a single platform
or cloud service.
Listen closely to any CIO today,
and you'll hear signs of a minor crisis in the making. Currently, an
estimated 25% of application workload is delivered as virtual machines
As this trend continues in 2009, we're likely to see a VM Tsunami that
swamps legacy approaches to application delivery and management. JeOS,
in and of itself, is not a solution. JeOS is an enabler for a
new and better way to deploy applications. But this approach requires a
broader lifecycle strategy that allows you to realize all of the cost
and agility benefits without being overwhelmed by unintended
consequences and unexpected costs. The good news is that these risks
can be mitigated through a managed lifecycle approach to enterprise
application virtualization, which begins with JeOS and ends with
applications that have been set free.