Steve Bigelow: The popularity of cloud computing
has led to an increasingly diverse set of cloud
technologies, which in turn, has led to some
confusion around important cloud paradigms,
specifically, public and private cloud
technologies and how they intersect in the form of
hybrid cloud and multi-cloud models. A public
cloud is a set of services and resources that
offers a complete virtual infrastructure available
on demand and paid for based on actual usage. A
user creates an account with a public cloud
provider, such as AWS, or Microsoft, or Google,
and then deploys those cloud services and
resources as needed to handle computing tasks. You
can run a few basic instances or you can architect
a highly scalable and comprehensive enterprise
computing environment. Organizations use private
clouds to deploy services and resources within
their own data centers, the business owns the
environment, which is typically used by a
relatively small number of employees and
customers, and provides limited services and
scalability. In theory, private clouds offer the
DIY conveniences of a public cloud, while still
enabling the business to maintain direct control
over the infrastructure. A hybrid cloud is
basically a connection between a public cloud and
a private cloud. Ideally, a business could use a
hybrid cloud model to support seamless workload
migrations between private and public cloud
environments. A workload might also run
redundantly in both environments for greater
resiliency, or components running in each
environment could interoperate. Ultimately, a
hybrid cloud offers more flexibility and more
control than either a public or private cloud
could do alone. A hybrid cloud is usually
associated with cloud bursting, moving resources
from the private cloud to the public cloud when
demand exceeds on-premises capacity. But cloud
bursting is uncommon in practice. Private and
public clouds can and do work together, but
they're rarely an apples to apples match, which
makes cloud bursting technically challenging.
Ideally, a multi-cloud environment incorporates
services from two or more public cloud providers.
Public clouds can have similar capabilities, but
they're not necessarily equal. So there are
advantages to being able to pick and choose across
providers. First, different business units have
different IT needs. For example, Google Cloud is
recognized for its AI services. So data scientists
might turn there for machine learning projects. At
the same time, AWS offers a mature and diverse set
of infrastructure services, such as DNS routing,
caching, and load balancers. Pretty much
everything developers might need in order to
deploy a complex enterprise application in the
public cloud. The idea here is that a business can
use almost any public cloud services to support
its own specific goals. Second, organizations want
to avoid vendor lock in. In theory, an
organization builds its cloud environment in a way
that enables straightforward workload portability
should it ever decide to switch providers. In
practice, this goal is rarely enough to justify a
formal multi-cloud strategy because public clouds
are not interchangeable. Differences in resources,
services, APIs, and other components make it
difficult to migrate complex applications without
some amount of re-architecting. Finally, a
multi-cloud environment typically involves two or
more public cloud providers. Notice we didn't
include private clouds. That is, connecting a
private cloud to a public cloud doesn't make it a
multi-cloud as we're defining it. However, almost
any multi-cloud strategy will likely still involve
some amount of on-premise physical, virtual, and
even private cloud infrastructure. Just remember
that none of these scenarios are either/or
choices. To learn more about cloud computing, be
sure to visit www.searchcloudcomputing.com.