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.
