Whether SaaS, IaaS or PaaS, one of the central concepts of all layers of
cloud computing is multi-tenancy. If there is no shared resource in a
deployment, it's difficult to justify calling that deployment "cloud."
Even NIST makes it more or less official within its formal definition of
cloud computing, which reads, in part:
Essential Characteristics: Resource pooling. The provider's computing
resources are pooled to serve multiple consumers using a multi-tenant model,
with different physical and virtual resources dynamically assigned and
reassigned according to consumer demand.
In most SaaS offerings, the multi-tenancy is manifold - the servers, the
application code, the database and even the individual tables or pages within
the database might be shared among different customers and users of the
In IaaS, multi-tenancy is implemented via virtualization tech... (more)
Despite my shaky prediction performance in 2011, I'm going to try again.
Last year, my best predictions were based on some sort of specialized
knowledge or insight, and the worst came from looking into the macro
environment and making guesses. So, this year's predictions emphasize the
former approach, yet hopefully avoid sounding like claims such as "the market
1. 2012 will be the Year of the Storefront in the cloud.
Admittedly, this is a somewhat self-serving prediction, since Standing Cloud
is (among other things) a storefront. But based on the variety of offerin... (more)
Virtual appliances are binary files representing the complete and fully
configured state of a server. They are a popular approach to the deployment
of application software in virtualized data centers as well as in public or
private clouds, because once the "golden master" is created, deployment of
that server state is fast, easy, and repeatable. However, there are
significant disadvantages to the use of virtual appliances. Model-driven
deployment is a new approach that largely eliminates these issues, better
matches today's fast-moving, agile environments, and takes full advantag... (more)
In an application deployed directly on IaaS, you know and control everything
about the database; in a SaaS application you know little and control
But how does it work in PaaS?
Since a PaaS is essentially a container that runs application code, and
virtually every application requires a persistent data store, most PaaS
offerings provide some kind of database services. Not surprisingly, Resource
PaaS offerings most closely resemble SaaS in that they hide more deployment
details, while Server PaaS offerings are more flexible but potentially more
complex. (For more on Res... (more)
Like an automobile, a web application needs occasional maintenance and
management over its life cycle. Although it doesn't need oil changes, it will
probably need version upgrades. There may not be manufacturer recalls, but
sometimes servers fail or hang. An application doesn't need to be washed and
detailed, but it does need to be backed up. And both cars and applications
need occasional performance tuning.
This article provides a complete list of the system management functions that
need to be performed on a standard architecture web application, with a
particular emphasis on ... (more)