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Cloud Computing�

Amazon Web Services - introduction

Dr. Mohammad Shoab

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Infrastructure as a service

Users can ask for

Computing nodes (servers)
Storage
Networking (between nodes)

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AWS: Infrastructure as a service

Computing

Elastic Compute Cloud (EC2)

Storage

Simple Storage Services (S3)
Elastic Block Stores (EBS)
Glaciar
DynamoDB

Other services

Simple Queue Service

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EC2

A typical example of utility computing
functionality:

launch instances with a variety of operating systems (windows/linux)
load them with your custom application environment (customized AMI)
Full root access to a blank Linux machine
manage your network’s access permissions
run your image using as many or few systems as you desire (scaling up/down)

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Backyard…

Different from Vmware & VPC

- high performance

Hardware contributions by Intel (VT-x/Vanderpool) and AMD (AMD-V)
Supports “Live Migration” of a virtual machine between hosts

We will dedicate one class to Xen...

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Amazon Machine Images

Public AMIs: Use pre-configured, template AMIs to get up and running immediately. Choose from Fedora, Movable Type, Ubuntu configurations, and more

Private AMIs: Create an Amazon Machine Image (AMI) containing your applications, libraries, data and associated configuration settings

Paid AMIs: Set a price for your AMI and let others purchase and use it (Single payment and/or per hour)

AMIs with commercial DBMS

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Normal way to use EC2

For web applications

Run your base system in minimum # of VMs
Monitoring the system load (user traffic)
Load is distributed to VMs
If over some threshold 🡪 increase # of VMs
If lower than some thresholds 🡪 decrease # of VMs

For data intensive analysis

Estimate the optimal number of nodes (tricky!)
Load data
Start processing

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Tools (most are for web apps)

Elastic Block Store: network-attached persistent storage, can be attached to each VM instance
Elastic IP address: programmatically remap public IP to any instance
Virtual private cloud: bridge private cloud and AWS resources
CloudWatch: monitoring EC2 resouces
Auto Scaling: conditional scaling
Elastic load balancing: automatically distribute incoming traffic across instances

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Type of instances

Standard instances (micro, small, large, extra)

E.g., small: 2GB Memory, 1EC2 Compute Unit (Xeon processor?), some GBs of instance/EBS storage (i.e., root volume)

High-CPU instances

More CPU with same amount of memory

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Pricing

Check the website

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Amazon machine images(AMIs)

Virtual machine images
When users ask for a specific system

AWS loads the corresponding AMI and creates the virtual machine (VM)

The user access the VM instance, no different from accessing a real remote server

AMIs cover most common systems

Linux distributions
Windows server

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AMIs with special software

IBM DB2, Informix Dynamic Server, Lotus Web Content Management, WebSphere Portal Server
MS SQL Server, IIS/Asp.Net
Hadoop
Open MPI
Apache web server
MySQL
Oracale 11g
…

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Access methods

Web interface
Command line
Programming Interface

E.g., boto python library

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Simple Storage Service (S3)

Write,read,delete objects 0byte-5TB, single PUT <5GB
Namespace: two levels: buckets, keys
Accessible using URLs

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S3 namespace

Amazon S3

bucket

object

bucket

object

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Amazon S3

mculver-images

media.mydomain.com

Beach.jpg

img1.jpg

img2.jpg

2005/party/hat.jpg

public.blueorigin.com

index.html

img/pic1.jpg

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Accessing objects

Bucket: keke-images, key: jpg1, object: a jpg image

accessible with

https://keke-images.s3.amazonaws.com/jpg1

mapping your subdomain to S3

with DNS CNAME configuration
e.g. media.yourdomain.com 🡪 media.yourdomain.com.s3.amazonaws.com/

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Access control

Access log
Authorization

ACL: AWS users, users identified by email, any user …

Digital signature to ensure integrity
Encrypted access: https

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Pricing

Check the website

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Elastic Block Store

An EBS volume is a virtual disk of a fixed size with a block read/write interface. It can be mounted as a filesystem on a running EC2 instance where it can be updated incrementally. Unlike an instance store, an EBS volume is persistent.

(Compare to an S3 object, which is essentially a file that must be accessed in its entirety.)

Fundamental operations:

CREATE a new volume (1GB-1TB)
COPY a volume from an existing EBS volume or S3 object.
MOUNT on one instance at a time.
SNAPSHOT current state to an S3 object.

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EBS is approx. 3x more expensive by volume and 10x more expensive by IOPS than S3.��

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Use Glacier for Cold Data

Glacier is structured like S3: a vault is a container for an arbitrary number of archives. Policies, accounting, and access control are associated with vaults, while an archive is a single object.
However:

All operations are asynchronous and notified via SMS.
Vault listings are updated once per day.
Archive downloads may take up to four hours.
Only 5% of total data can be accessed in a given month.

Pricing:

Storage: $0.01 per GB-month
Operations: $0.05 per 1000 requests
Data Transfer: Like S3, free within AWS.

S3 Policies can be set up to automatically move data into Glacier.

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Durability

Amazon claims about S3:

Amazon S3 is designed to sustain the concurrent loss of data in two facilities, e.g. 3+ copies across multiple available domains.
99.999999999% durability of objects over a given year.

Amazon claims about EBS:

Amazon EBS volume data is replicated across multiple servers in an Availability Zone to prevent the loss of data from the failure of any single component.
Volumes <20GB modified data since last snapshot have an annual failure rate of 0.1% - 0.5%, resulting in complete loss of the volume.
Commodity hard disks have an AFR of about 4%.

Amazon claims about Glacier is the same as S3:

Amazon S3 is designed to sustain the concurrent loss of data in two facilities, e.g. 3+ copies across multiple available domains PLUS periodic internal integrity checks.
99.999999999% durability of objects over a given year.

Beware of oversimplified arguments about low-probability events!

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DynamoDB

Simple table like storage

Weak schema
Back-end: a key-value store

Features

Scalable: Dynamo architecture
Reliable

Replicas over multiple data centers

Speed

Fast, single-digit milliseconds

Secure

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Data Model

table

Container, similar to a worksheet in excel,
Cannot query across domains

Item

Item name
item name ->(Attribute, value) pairs
An item is stored in a domain (a row in a worksheet. Attributes are column names)

Example

domain: “cars”
Item 1: “car1”:{“make”:”BMW”, “year”:”2009”}

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Primary key of table

Single key (hash)
Hash-range key

A pair of attributes: first one is hash key, 2^nd one is range key.
Example: Reply(Id, datetime, …)

Data type

Simple: string and number
Multi-valued: string set and number set

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