Cloud Computing

Define MAINTAINABILITY in cloud computing context

* A measure of how long to recover from an error * A measure of how long to upgrade/update

Tenets/principles of SOA

* Boundaries are explicit - clear what code is inside/outside the service * Services are autonomous - independent implementation, deployment, and environment * Services share schema and contract - schema: format and content of messages - contract: function signatures exposed

What are the benefits of the cloud?

* Global reach *Instant and dynamic supply *IT cost savings and expertise *Auto-scaling *High availability

What is referred as Scaling-out(horizontal scaling)

* Mechanism deployed in the cloud architectures * Mapping certain capacity/throughput to scale-unit * scale-units are identical in all aspects * Scaling up or down by managing scale-units which run simultaneously

What are some attributes of SOA?

* Modularization of programming(provide API for accessing data) * Well defined interfaces to allow each service to be update independently * Can expose API for others to consume * Example, amazon,netflix, is built on SOA

Scale-up (vertical scaling)

* scaling with hardware improvements *Has limitations as computers can only grow so large *Cannot be done dynamically, requires reboot *Expensive

What are some attributes of HTTP?

HTTP uses one-time TCP port 80 connection for each response/reply (stateless)

What does IETF stands for?

IETF stands for internet engineering task force

What is a stateless protocol?

In computing, a stateless protocol is a communication protocol in which no information is retained by the sender or receiver

What does SLA mean?

Service Level Agreement... Is the Guaranteed availability from the cloud provide, Usually measured in three 9's

What is SaaS?

Software as a Service - Provides ready-made environment - Provides a higher-level API which provides a service that cloud apps consume - Used to create cloud services, for example, Azure SQL, Heroku, REST weather API

Name Richardson Maturity Model?

Steps to glory of REST: level 0: The swamp POX level 1: Resources level 2: HTTP Verbs level 3: Hypermedia Controls

What are the different Cloud Architectures?

3-tier, SOA, Microservices, REST, NoSQL,Scale

What is a 3-Tier Architecture?

A 3-Tier Architecture is a client-server architecture in which the functional process logic, data access, computer data storage, and user interface are developed and maintained as independent modules

What is a LAN?

A LAN is a group of computers and network devices connected usually within the same building

What is Amazon Glacier?

Amazon glacier is a archival storage/ backup storage

What is AWS IAM?

Amazon's service which allows : -users to be created -users can be added to a group User's are provided with a secret key and access key

What is Amazon S3?

Amazon S3 stores information in buckets that can be uploaded and retrieved by using API's - Unstructured/flat - highly scalable object storage

What are some cloud usages:

Azure/AWS storage, data, VM, Apps

What is Cloud Front?

Cloudfront is a inexpensive content delivery network that delivers data, videos, applications, and API's to customers worldwide

What is the PUE? and what is the formula?

Power Usage Effectiveness(PUE) PUE = Total Facility power / IT equipment power

What is the goal of caching?

The goal of caching is is never having to generate the same response twice

Describe the evolution of the cloud?

Mainframe - 1970 client-Server - 1980 Web - 1990 SOA - 2000 Cloud - 2010

What is the Mean Time to Failure formula?

Mean Time to Failure = (total time in service) / (number of failures)

What is Power Usage Effectiveness(PUE)?

Measures the power effectiveness of a data center

Define AVAILABILITY in cloud computing context

The percent chance that the system is up and operating

Choose all of the following which are constraints needed for an architecture to be RESTful 1. HTTP 2.Three Tier Architecture 3. Client Server Architecture 4. SOAP compliant 5. Stateless 6. Uniform Interface

1. Client Server 2. Stateless 3. Uniform Interface

What are the essential characteristics of cloud computing?

1. On-demand, self-service usage 2. Ubiquitous network access 3. Resource pooling / multi-tenancy 4. Rapid elasticity 5. Measured Usage

What are the OSI layers?

1. Physical 2. Data Link 3. Networking 4. Transport 5. Session 6. Presentation 7. Application

Name the different cloud computing deployment models

1. Public cloud (owned by private business utilized by the public) 2. Community cloud(same as public just limited to certain organizations) 3. Private cloud(cloud onwed by a single organization and used multiple divisions) 4. Hybrid(combination of private/public)

What are the REST Anti-Patterns? (typical examples of attempted RESTful HTTP usage that create problems and show that someone has attempted, but failed, to adopt REST ideas)

1. Tunnelling everything through GET 2. Tunnelling everything through POST 3. Ignoring caching 4. Ignoring response code 5. Misusing cookies 6. Forgetting hypermedia 7. ignoring MIME types 8. Breaking self-descriptiveness

What are the six constraints of REST architecture?

1. Uniform Interface (defines interface between client and server) 2. Stateless (Server contains no client state) 3. Client-Server (needed for standards to define the contract between client and service) 4. Cacheable(Generates the same response twice) 5. Layered System (client does not have direct connection to the server) 6. Code on Demand (server can transfer logic to the client to execute)

What is a WAN?

A WAN connects several LAN's and may be limited to an enterprise (corporation or an organization)

Who invented TCP and IP?

Bob Kahn and Vint Cerf

What is a client? in a client-server architecture

Client browsers requests, receives, and displays web resources

Which is not a key tenet of a Service in SOA? a. Services share contacts b. Explicit Boundaries c. Communication over HTTP d. Autonomous services

Communication over HTTP

What does DCIE stands for? And what does it mean?

Data Center Infrastructure Efficiency Its a performance improvement metric used to calculate the energy efficiency of a datacenter

In SOA services should be tightly-coupled so that they can be upgraded easily together? True or False

False

What is the key difference between HTTP/1.0 and HTTP/1.1?

HTTP/1.0 creates a new TCP connection for every request and HTTP/1.1 allows for persistent connection (One TCP connection until the service/connection is terminated)

Define RELIABILITY in cloud computing context

How long a system provides proper operation(the amount of time is expected to be up and running)

What is IaaS ? (abbreviation)

Infrastructure as a Service. - IT infrastructure offered as a service (compute, storage, Network). - Provides high level administrative control (what machine types, and OS) - Examples, VM offered by Azure and Amazon(EC2), Load Balancers, IP addresses

Cloud enablers

Internet, HTTP, SOA, Virtualization, Data Centers

Define Client and Server Architecture

Network architecture which allows clients can make requests and servers to respond

What does OSI model stands for and what does it mean?

OSI stands for Open System Interconnection This model characterize and standardizes the communication functions of a telecommunication or computer system.

How are SOAP and REST different?

REST: *Exposing a public API over the internet *Accessing named resources through a single consistent interface *Nouns *Reach and ubiquity * All clients have required access --HTTP SOAP: * exposes operations(verbs) * exposes back-end business logic

Who was the person credited with the create of Representational State Transfer (Rest)? 1. Roy Fielding 2. Tim Berners-Lee 3. Vint Cerf 4. Jessie Frazelle 5. YE

Roy Fielding

What is SOA?

SOA stands for Service Oriented Architecture

Who Invented HTTP?

SR. Tim Berners-Lee

SOAP is often implemented by "tunneling" through HTTP? True or False

True

What is Elastic Block Storage? (EBS)

Volume based storaged that is independent of EC2 VM Block storage that is good for a file system or Databases

What is a server? in a client-server architecture

Web server sends objects in response of a request

What is the availability formula?

availability = uptime / (total time)

What is cloud computing definition?

cloud computing is a model for enabling ubiquitous, convenient, on-demand network access, to a shared pool of computer resources(networks, servers, storage, applications) that can be rapidly provisioned and released with minimal management effort. It it composed of 5 essential characteristics, 3 service models, and four deployment models.

What is URI?

uniform resource identifier (URI) is a string of characters used to identify a name of a web resource.