chapter 3 book

measurable benefits to cloud consumers

- on demand access to pay as you go computing resources on a short term basis, and the ability to release these computing resources when they are no longer needed - the perception of having unlimited computing resources that are available on demand - the ability to add or remove IT resources at a fine grained level - abstraction of the infrastructure so applicaitons are not locked into devices or locations

horizontal scaling points

1) less expensive 2) IT resources instantly available 3) resource replication and automated scaling 4) additional IT resources needed 5) not limited by hardware capacity

vertical scaling points

1) more expensive 2) IT resources normally instantly available 3) additional setup is normally needed 4) no additional resources needed 5) limited by maximum hardware capacity

cloud computing

Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model is composed of five essential characteristics, three service models, and four deployment models.

On premise

IT resource hosted in a conventional IT enterprise within an organizational boundary is considered to be located on the premise of an IT enterprise

vertical scaling

When an existing IT resource is replaced by another with higher or lower capacity, vertical scaling is considered to have occurred. Specifically, the replacing of an IT resource with another that has a higher capacity is referred to as *scaling up* and the replacing an IT resource with another that has a lower capacity is considered *scaling down*.

capacity planning: match strategy

adding IT resource capacity in small increments, as demand increases

capacity planning: lead strategy

adding capacity to an IT resource in anticipation of demand

capacity planning: lag strategy

adding capacity when the IT resource reaches its full capacity

horizontal scaling

allocating or releasing of IT resources that are of the same type is referred to as horizontal scaling. horizontal allocation of resources is referred to as scaling out and the horizontal releasing of resources is referred to as scaling in

cloud service

any IT resource that is made remotely accessible via a cloud

business drivers for cloud computing

capacity planning, cost reduction, and organizational agility

limited portability between cloud providers

challenging to move between providers

multi regional compliance and legal issues

consumers arent often aware of the physical location of their IT

reduced governance control

different factors reduce the amount of control that an organization possesses by using cloud services. the quality of solutions can be jeopardized, and farther geographic distance can require additional network hops that introduce more problems

cloud

distinct IT environment that is designed for the purpose of remotely provisioning scalable and measured IT resources

clustering

group of independent IT resources that are interconnected and work as a single systems. general prerequisite is that they have reasonably identical hardware and operating systems

organizational agility

measure of an organizations responsiveness to change. its scalability

increased security vulnerabilities

moving of business data to the cloud means that the responsibility over data security becomes shared with the cloud provider. overlapping of trust boundaries and increased exposure of data provides opportunity for attack

IT resource

physical or virtual IT-related artifact that can be either software based or hardware based

grid computing

provides a platform in which computing resources are organized into one or more logical pools. much more loosely coupled and distributed.

reduced investment and proportional costs in cloud computing

public cloud providers charge less based on mass-acquisition of IT resources that are made available to consumers via attractively priced leasing packages. most common economic rationale for investing in cloud based IT is reduction of up front IT investments.

virtualization

tech platform used for the creation of virtual instances of IT resources. a layer of virtualization allows physical IT resources to provide multiple virtual images of themselves so that their underlying processing capabilities can be shared by multiple users.

Cloud service consumer

temporary runtime role assumed by a software program when it accesses a cloud service

cost reduction

two costs need to be accounted for 1) the cost of acquiring new infrastructure 2) cost of its ongoing ownership