Your Coffee Shop Uses Cloud Computing

Figure 2. The coffee shop with patterns applied. Numbers correspond to one of the five cloud application design

phases: (1) decomposition, (2) workload, (3) data, (4) component refinement, and (5) elasticity and resiliency. (Patterns

are derived from our previous work: www.cloudcomputingpatterns.org.)

In IT applications, we often find

a similar impact from workload,

where input complexity is similar for

all requests, but request handling in

the back end has higher complexity.

Assigning all the components of such

an application to one server and scal

ing the application by adding servers

is suboptimal under such conditions.

This would equate to building addi

tional coffee shops in warmer regions

to handle the higher demand for frozen

coffee products, rather than just adding

more blenders to one coffee shop.

Phase 3: Data (State)

As a prerequisite for later scalabil

ity and resiliency considerations, the

location where data are stored and

data consistency are extremely impor

tant. This is because the elastic scal

ing of resources and their replacement

in case of failures are significantly

affected by state information, which

might need to synchronize with newly

provisioned resources or could be lost

during a resource failure. We differen

tiate two types of state.

Session state

is the state of a user’s interaction with

an application — for example, a shop

ping basket in an online shop.

Appli

cation state

is the data an application

handles, such as the customer data, the

currently processed orders, and so on.

Two patterns characterize the means

by which an application handles these

state types

•

Stateful component.

Multiple

stances of a scaled‐out applica

tion component synchronize their

internal state to provide a unified

behavior.

Christoph Fehling, Frank Leymann, and Ralph Retter •

University of Stuttgart

IT applications and physical businesses often face similar challenges: customers

have to be served quickly; throughput and availability should be increased. Here,

the authors cover the architectural design phases of a cloud application and

describe common best practices relevant in each phase. To avoid IT complexity,

they use a coffee shop as a real-world analogy.

T experts have a long‐established relationship

with coffee and related products — you could

even call it love. Coffee shops making our

favorite products are places to relax and work,

but they can also inspire IT architectures.

can transfer a coffee shop’s efforts at increasing

the amount of processed orders while optimizing

resource use to IT application architectures.

Here, we examine cloud computing patterns,

capturing best practices for building and managing

cloud applications. We abstracted these patterns

from existing applications, architecture guidelines,

and documentation of cloud offerings to express

common, underlying architectural concepts. Each

pattern is a similarly structured and human‐read

able document describing an abstract solution

to address reoccurring architectural problems in

cloud applications. Patterns avoid provider‐ or

implementation-language‐specific terminology,

thus documenting design knowledge gained from

practice in a provider‐independent form.

Patterns and the Coffee

Shop Analogy

Patterns can describe the following:

•

cloud environments from different providers

and how they’re hosted;

•

the behavior of different cloud offerings and

when to use a certain offering; and

•

how to design applications using these offer

ings, and manage them at runtime.

Using patterns, IT architects can compare cloud

providers in terms of those patterns they support,

and can design applications without consider

ing the specific offering’s idiosyncrasies too early

in the design process. Furthermore, the design

knowledge captured in patterns can be more easily

applied to different cloud providers.

For fundamental cloud computing patterns, we

show that coffee shops similarly handle the five

design phases of cloud applications: decomposi

tion, workload, data (state), component refinement,

and elasticity and resiliency. In other words, you

can experience all the design phases first-hand by

buying a coffee.

Figure 1 shows the coffee shop we consider

as an analogy. Customers entering the shop form

a line waiting to place their orders at a set of

cash registers. Employees take the order, collect

the payment, and write the customer’s name and

desired product on a cup. They then place this cup

on a separate table, where it waits for processing

by baristas handling the coffee machine for regu

lar coffee products, such as drip coffee or espresso.

Baristas also operate a set of blenders for frozen

coffee products. After processing, a barista places

the finished product on a second table, where the

customer retrieves it; here, the information on the

cup is used as a correlation identifier.

Phase 1: Decomposition

By nature, clouds are large distributed systems pro

viding resources for computation, communication,

and storage.

Monolithic applications that com

prise one component and use a single server for

hosting do not benefit from this distributed envi

ronment. Instead, cloud application architectures

must distribute an application’s functions among

IC-18-05-VftC.indd 52

04/08/14 2:14 PM

Images can mislead the viewer by modifying, inserting or removing objects from the scene. Many photo editing applications include tools that can remove objects cleanly from their surroundings with a few clicks. This is known as inpainting.
An early method was to fill the void left in the image by smoothly interpolating inwards, based on sampling the pixels at the edge of the missing area. Other techniques include seam carving, content-aware image resizing in which an algorithm establishes the image's important areas in order to remove or expand sections around them without affecting the subject of the image.

Read more at: http://phys.org/news/2014-11-forging-photo-easy-fake.html#jCp

Faking photographs is not a new phenomenon. The Cottingley Fairies seemed convincing to some in 1917, just as the images recently broadcast on Russian television, purporting to be satellite images showing the MH17 airliner being fired upon by a jet fighter, may have convinced others.

Read more at: http://phys.org/news/2014-11-forging-photo-easy-fake.html#jCp

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Your Coffee Shop Uses Cloud Computing

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Your Coffee Shop Uses Cloud Computing

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