Cloud Delivery and Hosting Models - Deploying and Managing a Cloud Infrastructure - page 177

it will show up as a single virtual storage capacity or drive with 100 GB available storage,
and the user will have no idea where the actual data will be stored physically.
The multitenant architecture of the cloud separates the storage drives or allocated storage
areas of each user from each other. This is usually done through the management soft-
ware or virtualization management software that creates a logical boundary between each
storage instance. It decides where each data object will be kept and stored, how it will be
accessed and managed, and how other administrative processes that ensure the cloud stor-
age performs as expected are performed. For security reasons, the data is usually encrypted
by default when stored.
Software Software orchestration is perhaps the most common form of orchestration on
the cloud. It is performed by the core cloud software itself. In fact, orchestration is a key
implementation of SaaS offerings. SaaS orchestration manages how each software instance
will be accessed, creation and assignment of APIs, allocation of server resources, network
connectivity, and port access. This enables software to be accessed by multiple users simul-
taneously, each having a separate interface and without interfering with the work and data
of other users. This is the core function of multitenancy.
Network Network resources serve as the backbone of any IT solution. Its importance has
become much more prevalent in recent times, specifically with cloud solutions that heavily
depend on the underlying network infrastructure to deliver IT solutions and services to end
users globally. Network orchestration involves a substantial amount of work that needs to
be organized and aligned to ensure availability of network services to all nodes, software,
and requesting services. Network orchestration usually happens in real time, so the changes
are applied and take affect instantly. These changes may be on an individual node or the
entire network. Network orchestration also helps in reinstating a network when problems
disrupt normal network operations.
Summary
In this chapter, you learned about the different delivery and hosting models of cloud
computing. Some people may initially confuse delivery with the service models such as
SaaS and IaaS, which is understandable because service and delivery are usually tied
together. But these topics are covered in Chapter 12.
We reviewed the three main delivery models—private, public, and hybrid—and also
the community delivery model. In a private cloud, service is dedicated to a single entity or
organization, yet its deployment may be both on-premises or off-premises, as is the case of
co-location and private cloud hosting services. Co-location and private cloud hosting offers
the same control as on-premises solutions, but the performance and security may be dif-
ferent because both hosting models have to be accessed via the public Internet. Even using
VPN and other tunneling protocols, running through public infrastructure may still pose a
certain level of security risk as compared to running everything on-premises.