amazon web services - · pdf fileamazon web services • a broad set of services that...

Amazon Web Services

Università degli Studi di Roma “Tor Vergata” Dipartimento di Ingegneria Civile e Ingegneria Informatica

Corso di Sistemi Distribuiti e Cloud Computing A.A. 2015/16

Valeria Cardellini

Amazon Web Services •  A broad set of services that provides developers with

global compute, storage, database, and more advanced services, such as analytics, application and deployment services, messaging

Valeria Cardellini - SDCC 2015/16

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•  Mostly popular for IaaS services and primarily for its elastic compute service EC2

•  A market leader •  See 2015 Magic Quadrant

for Cloud Infrastructure as a Service by Gartner

•  See AWS analyst reports

Which services (partial list)

•  Compute –  Elastic Compute Cloud (EC2)

and related services (Auto Scaling, Elastic Load Balancing)

–  EC2 Container Service –  Elastic Beanstalk

•  Storage & Content Delivery –  Simple Storage Service (S3) –  CloudFront –  Glacier –  Elastic File System (EFS)

•  Database –  DynamoDB –  Relational Database Service

(RDS) –  ElastiCache

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•  Networking -  Virtual Private Cloud (VPC) -  Route 53

•  Analytics -  Elastic MapReduce (EMR) -  Kinesis -  Data Pipeline

•  Application Services –  AppStream –  Simple Queue Service (SQS) –  CloudSearch –  Elastic Transcoder

•  Administration & Security –  CloudWatch –  Identity and Access Management (IAM)

•  Enterprise Applications –  WorkSpaces –  WorkDocs

Full list of service from the dashboard


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AWS global infrastructure •  AWS Regions aws.amazon.com/about-aws/globalinfrastructure/

–  Geographically dispersed –  Current regions: US East (Northern Virginia), US West

(Oregon), US West (Northern California), EU (Ireland), EU (Frankfurt), Asia Pacific (Singapore), Asia Pacific (Tokyo), Asia Pacific (Sydney), Asia Pacific (Seoul), South America (Sao Paulo)

–  Special AWS GovCloud region for US government agencies and customers (security issues!)

•  Some services are global, i.e., do not require AWS region selection –  E.g., S3 is a global service

•  Some services are not supported in all the regions –  See

aws.amazon.com/about-aws/global-infrastructure/regional-product-services/


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Elastic Compute Cloud (EC2) •  Provides resizable compute capacity in the cloud

–  Allows to increase/decrease capacity (start/stop instances) within minutes

–  From one to thousands of server instances can be launched simultaneously

•  Instances can be configured for memory, number of vCPUs, and storage by choosing T-shirt sizes

•  Pricing: pay-per-use on hourly basis •  Guarantees complete control over instances

–  Root SSH access, GUI, command line tools, APIs

•  Offers advanced services –  Elastic Block Store (EBS) –  Elastic Load Balancer (ELB) –  CloudWatch + AutoScaling –  Elastic IP


EC2 instances: types


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•  Computing power of EC2 instances expressed as number of core and EC2 Compute Units (ECU) -  1 ECU = equivalent CPU capacity of a 1.0-1.2 GHz 2007

Opteron or 2007 Xeon processor -  See aws.amazon.com/ec2/pricing/ for pricing

•  EC2 instance types aws.amazon.com/ec2/instance-types/ –  General-purpose

•  Various “T-shirt sizes”: nano, micro, small, medium, large, xlarge, 2xlarge

•  Micro instances: very low-cost instance option (included at no charge in AWS Free tier), providing a small amount of CPU resources (good choice for SDCC project development!)

–  Compute optimized •  medium, large, xlarge, 2xlarge, 4xlarge, 8xlarge (up to 32 vCPUs)

–  Memory optimized •  xlarge, 2xlarge, 4xlarge, 8xlarge (up to 244 GiB)

–  Storage optimized •  xlarge, 2xlarge, 4xlarge, 8xlarge (up to 24 x 2000 HDD)

–  GPU instances (NVIDIA GPUs) •  2xlarge, 8xlarge

EC2 instances: pricing •  On-demand instances

–  Billing per-hour with no long-term commitments –  Read carefully the pricing:

•  “Pricing is per instance-hour consumed for each instance, from the time an instance is launched until it is terminated or stopped. Each partial instance-hour consumed will be billed as a full hour”

•  Reserved instances –  One-time payment to reserve an instance for 1 or 3 years –  Significant discount on hourly usage charge (up to 75%)

•  Spot instances –  Enable users to bid for unused EC2 capacity –  Spot price fluctuates in real-time according to supply and

demand –  Run whenever the user bid exceeds the current spot price –  Can be interrupted by Amazon –  Allow to lower computing costs for time-flexible, interruption-

tolerant tasks


EC2 instances: pricing •  Spot instances (continue)

–  Pricing history can be examined before bidding –  New opportunities for business: companies such as CloudCheckr

and Flux7 (VyScale) offer new services for the spot instance market to optimize costs paid by AWS EC2 users


Amazon Machine Images

•  Amazon Machine Images (AMIs) are templates from which it is possible to create a virtual machine –  Contain a software configuration, including an operating

system –  Specified when launching an instance (first step)

•  Created from scratch or bundled from existing EC2 instances

•  Once created, stored in S3 and identified by a unique identifier –  Personal use –  Available to other users


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EC2 locations •  Amazon EC2 is hosted in multiple locations world-wide

(AWS Regions) •  Each region is completely independent

•  Each region consists of one or more availability zones •  Availability Zones (AZ)

–  Distinct locations in the same region engineered to be insulated from failures in other availability zones

–  Availability Zones in a region are connected through low-latency links

–  Used to protect applications from failure of a single location


EC2 interface •  AWS management console •  Command Line Interface (CLI) •  API Tools

•  Third-party libraries –  E.g., boto, a Python interface to AWS

•  Third-party management frameworks –  E.g., Cloud42


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Elastic Block Store (EBS)

•  Provides persistent block-level storage volumes for EC2 instances –  Off-instance storage that persists independently from the life of an

EC2 instance –  EBS volumes from 1 GB to 1 TB

•  EBS volumes can be used at instance’s boot partitions or attached to running instances as standard block devices –  A volume can only be attached to one instance at time, but many

volumes can be attached to a single instance –  EBS volumes can be attached only to instances in the same

availability zone

•  EBS volumes automatically replicated within the same Availability Zone to avoid data loss

•  EBS provides the ability to create point-in-time snapshots of volumes that can be stored using S3


Elastic IP & Virtual Private Cloud

•  Elastic IP –  IP address is not associated with a particular instance but

with a user account –  The user controls an elastic IP address until she/he explicitly

releases it –  Allows to mask instance or availability zone failures by

quickly remapping the elastic IP address to another instance/load balancer

•  Virtual Private Cloud –  Enables enterprises to connect their existing infrastructure to

a set of isolated AWS compute resources via a Virtual Private Network (VPN) connection


CloudWatch

•  Provides monitoring for AWS resources (e.g., EC2 instances, DynamoDB tables) and applications running on AWS

•  Used to collect and track metrics •  Useful also for cost monitoring

–  E.g., to stop under-used instances


CloudWatch concepts •  Metric

–  Time-ordered set of data points –  PutMetricData API allows users to create custom metrics

•  Statistics –  Metric data aggregated over specified periods of time –  Available statistics: min, max, sum, average, sample count –  Retrieved by GetMetricStatistics API

•  Period –  Length of time associated with a specific CloudWatch statistic –  Mesaured in seconds, ranges from 60 (one minute) to 1209600

(two weeks)

•  Alarm –  Watches a single metric over a specified time period –  Performs one or more actions based on the value of the metric

relative to a given threshold over a number of time periods


CloudWatch metrics

•  EC2 metrics –  CPU utilization: CPUUTilization!–  Disk usage: DiskReadOps/DiskWriteOps, DiskReadBytes/DiskWriteBytes

–  Data transfer: NetworkIn/NetworkOut!

•  Elastic Load Balancing metrics –  Latency!–  RequestCount: number of completed requests!–  HealthyHostCount/UnHealthyHostCount: number of

healthy/unhealthy instances in each Availability Zone!–  Count of HTTP response codes (2xx, 3xx, 4xx, 5xx) generated

by Load Balancer or back-end instances


CloudWatch interface •  Command line interface •  Libraries

–  Java, .NET, Python, Ruby, Node.js, …

•  CloudWatch API •  Amazon CloudWatch console (also for Android and IoS)


CloudWatch Alarms & Auto Scaling •  An alarm watches a single metric over a time period and performs

one or more actions based on the value of the metric relative to a given threshold over a number of time periods

•  Possible states: OK, ALARM, INSUFFICIENT_DATA!•  When an alarm changes its state, an action is invoked

–  Auto Scaling policy

Example Threshold = 3

minimum breach = 3 periods


Auto Scaling •  Auto Scaling allows to automatically scale EC2 capacity

up or down based on user-defined policies, health status checks, and schedules, e.g., –  Dynamically based on conditions specified by user (e.g.,

increasing CPU utilization of the Amazon EC2 instance) –  Predictably according to a schedule defined by user (e.g.,

every Friday at 13:00:00). •  Enabled by Amazon CloudWatch

–  Uses CloudWatch alarms

•  Included with EC2 –  No additional fee


Auto Scaling policies

•  Auto Scaling policy defines actions to take when an alarm state changes

•  For every monitored event, 2 policies to be defined: –  Scale-in policy –  Scale-out policy

•  Example: –  Scale-out: to add new Amazon EC2 instances in increments of 3

instances to the Auto Scaling Group when the average CPU utilization of the Amazon EC2 fleet goes above 70%

–  Scale-in: to remove Amazon EC2 instances in the same increments when CPU Utilization falls below 10%


Auto Scaling policies (2) •  A policy can be created or updated using PutScalingPolicy API with parameters (some): –  AdjustmentType: possible values are ChangeInCapacity, ExactCapacity, PercentChangeInCapacity!

–  Cooldown: amount of time after a scaling activity completes and before the next scaling activity can start

–  ScalingAdjustment: the amount of instances by which to scale (positive or negative)

!

"ScaleUpPolicy" : {! "Type" : "AWS::AutoScaling::ScalingPolicy",! "Properties" : {! "AdjustmentType" : "ChangeInCapacity",! "AutoScalingGroupName" : { "Ref" : "asGroup" },! "Cooldown" : "1",! "ScalingAdjustment" : "1"! }!}!


Elastic Load Balancing (ELB)

•  Automatically distributes incoming traffic across multiple EC2 instances


ELB features •  Detects unhealthy instances within a pool and

automatically reroutes traffic to healthy instances •  Enabled across multiple availability zones within a region

–  Not between availability zones in different regions! •  Uses a least loaded balancing policy •  Supports sticky sessions

–  Load balancer generated HTTP cookies –  Application-generated HTTP cookies

•  Supports HTTPS •  Enables the client to define an application health check

for the instances through the following parameters: –  Threshold, Interval, Target, Timeout,

UnhealthyThreshold!

•  Provides APIs to add/remove instances –  RegisterInstancesWithLoadBalancer!–  DeregisterInstancesWithLoadBalancer! 23


EC2 and related services problems •  General problems

–  No real-time billing –  Performance level of a single VM may be variable and there is

very little guarantees regarding the performance of seemingly identical virtual machine instance; e.g., see Resource Provisioning of Web Applications in Heterogeneous Clouds

–  Load balancing policy cannot be customized

•  CloudWatch problems –  Metric variation over a time interval is missing –  Request count considers only the requests processed by the

load balancer (system throughput behind the ELB)


Simple Storage Service (S3) •  Distributed, eventually consistent, key value data store •  Main features

–  Insert, write, read, delete operations on objects up to 5 TB each •  Objects cannot be manipulated (renamed, modified, relocated)

–  Objects are stored into buckets and retrieved via a unique key •  Flat structure, with no hierarchy as in a file system (e.g., buckets cannot be

nested) •  The bucket region can be selected and related objects will not leave the region

–  Accessible through REST interface –  Access control policies, as well as encryption for both secure transit

and secure storage on disk –  Objects are redundantly stored across multiple facilities in an

Amazon S3 Region •  PUT and COPY operations synchronously store data across multiple facilities

before returning SUCCESS –  Data integrity regularly verified using checksum –  Reduced Redundancy Storage (RRS): storage option to reduce

costs by storing data at lower levels of redundancy 25 Valeria Cardellini - SDCC 2015/16

Databases: DynamoDB •  Fully managed NoSQL database service that provides

fast and predictable performance with seamless scalability

•  Consistency model –  Eventually consistent reads (default) –  Strongly consistent reads

•  Automatically spreads the table data and traffic over a sufficient number of servers to handle the request capacity specified by the customer and the amount of data stored, while maintaining consistent, fast performance

•  Data items stored on SSDs and automatically replicated across multiple availability zones in a region

•  Integration with Elastic MapReduce


Databases: RDS •  Relational DB (MySQL, Aurora, …) •  Automatic configuration, management (software

patching, backup) and monitoring •  For MySQL, possible to associate one or more read

replicas •  Read carefully the AWS pricing!

–  Data transfer cost between AWS regions and out from RDS to Internet

–  Remember that you always pay on per-hour basis even if you use the service only for 10 seconds!


ElastiCache •  In-memory cache in the cloud to accelerate

applications that rely on slower disk-based storage and databases


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•  Supports two open-source in-memory caching engines: –  Memcached: widely adopted

memory object caching system

–  Redis: popular open-source in-memory key-value store that supports data structures such as sorted sets and lists; ElastiCache supports master/slave replication and Multi-AZ

•  Cautions: consider trade-offs when caching query results (read/write ratio)

Simple Queue Service (SQS)

•  Message queuing service that enables asynchronous message based communication between distributed components of an application

•  When a message is received, it becomes “locked” while being processed –  If the message processing fails, the lock will expire and the

message will be available again


DNS service: Route 53

•  Highly available and scalable DNS service –  Routing queries to infrastructure running in AWS and outside

AWS

•  Authoritative DNS server that answers DNS queries with low latency by using a global network of DNS servers –  Queries are routed to the nearest DNS server through IP

anycast –  Designed to automatically scale to handle very large query

volumes without any human intervention •  Routing to AWS resources

–  Latency-based routing: to the lowest-latency AWS endpoint available

–  Weighted Round Robin: probabilistic selection based on statically assigned weight


Big Data: Elastic MapReduce (EMR) •  Hadoop implementation of MapReduce running on

Amazon EC2 •  Input and output: Amazon S3, DynamoDB •  Allows to implement data processing applications in

many languages, including Java, Python, R •  Open-source projects that run on top of the Hadoop

architecture can be run on EMR –  Hive, Pig, Hbase, DistCp (distributed copy), Ganglia (monitoring

system), Impala (SQL query engine) and Hue (Hadoop UI)

•  Read carefully EMR pricing! –  You have to pay for: EMR

+ EC2 (at least medium size) + input/output (S3, DynamoDB)

–  Enable auto-terminate to create a transient cluster

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Big Data: Kinesis •  Cloud-based service for real-time data processing

over large, distributed data streams –  Manages the infrastructure, storage, networking, and

configuration needed for data stream processing, including data replication across three facilities in an AWS Region


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•  Input: event and log data from sources such as servers, desktops, mobile devices, sensors

•  Output: emits aggregated data to other AWS services: S3, EMR and Lambda

Content delivery: CloudFront •  Content delivery network on top of the Amazon distributed

storage infrastructure •  Delivers static, dynamic and streaming content using a

global network of edge replica servers •  Requests are routed to the closest edge replica through

DNS redirection •  Objects organized in distributions

–  A distribution identifies the origin server –  A distribution has a unique CloudFront.net domain name (e.g.

mydistribution.cloudfront.net)

•  An origin server is the location of the definitive version of an object –  This could be another ASW (S3 bucket, Amazon EC2 instance) or an

external origin server

•  With respect to other CDNs, pay-per-use pricing 33 Valeria Cardellini - SDCC 2015/16

Elastic Beanstalk •  Allows to deploy and manage applications leveraging AWS services

(EC2, S3, ELB, Auto Scaling, ElastiCache, SQS) but without the need to manage the corresponding services

•  Supports multiple application environments: Docker, Python, PHP, Node.js, .NET, Ruby, and Java

•  Features –  Allows to simply and quickly create and manage applications through

the console


–  When the developer creates the application environment, Elastic Beanstalk provisions the resources required to run it

–  Allows the developer to customize and configure the environment

–  Environment monitoring •  Pricing: no additional charge for Elastic

Beanstalk, the user pays only for the underlying AWS resources that the application consumes


Example: Web application on AWS

Some useful links

•  AWS Documentation aws.amazon.com/documentation/

•  AWS Articles & Tutorials https://aws.amazon.com/articles

•  Labs on AWS Educate portal aws.amazon.com/it/education/awseducate/members/

•  AWS Cloud Design Patterns en.clouddesignpattern.org/


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