如何無痛上雲端? 以Elastic Beanstalk Java Container為例

如何無痛上雲端?以Elastic Beanstalk Java Container為例

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Study Hsueh <ph.study@gmail.com> 2013-11-07

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上雲端

Deploy application to VPS (Virtual Private Server)

Cloud Web Application

or

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Cloud Web Application

Web Application is powered by cloud computing

Elasticity: 能隨時主動增加或刪減資源

Scalability: 資源的增減直接反應到負載上

Reliability: 應⽤用程式不會因為部分故障, 就無法提供服務

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Cloud Web Application

!4 http://media.amazonwebservices.com/architecturecenter/AWS_ac_ra_web_01.pdf

Architecture for Web Application Hosting

Cloud Web ApplicationBuild a cloud web application in AWS, you may need to know…

Elastic Load Balancing (ELB)

Auto Scaling

Cloud Watch

Elastic Compute Cloud (EC2)

Deployment

Management

Monitoring

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Infrastructure}

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有沒有簡單⼀一點的⽅方法上雲端?

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有! ⽤用PaaS吧!

PaaS: Platform as a Service

可是聽說PaaS....

White List

Black Box

Platform Dependent Services/Libraries

Software Versions

…etc

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試試Elastic Beanstalk吧:)

Elastic Beanstalk (EB)

Elastic Beanstalk是架構在AWS infrastructure上的PaaS服務, 使⽤用Elastic Beanstalk可以同時具備控制底層IaaS的能⼒力與PaaS的便利

Elastic Beanstalk的縮寫是EB (不是EBS, EBS是Elastic Block Store的縮寫)

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Elastic Beanstalk

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Elastic Beanstalk

Concept(1)

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Application

Environment

URL(CNAME)

Concept(2)

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Applications

Environments

URL

Supported Platforms

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Java Container

OS: x32/x64 Amazon Linux (2012.09)

Java: OpenJdk 1.6.0_24

Web Container: Tomcat 6.0.35 & 7.0.27

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Customization

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Elastic Beanstalk可以裝第三⽅方的程式嗎? 像是phantomjs, imagemagick…之類

或把Tomcat換成TomEE?

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Customizing Environment

Elastic Beanstalk provides two mechanisms to customize environment

Custom AMI

Configuration File (Oct 2. 2012)

including AWS resources (e.g. ElastiCache)

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Configuration File(1)Configuration File in WAR file

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Configuration File(2)

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Configuration File Example

YAML format

Deployment

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Upload WAR file

AWS Management Console

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AWS Toolkit for Eclipse

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$ git init # init git repository$ eb init # init EB Application Configuration$ eb start # start EB Environment$ git add . # track all files$ git commit -m “Initial Commit” # commit$ git aws.push # push to EB

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Command-line interface

Deploying with Zero Downtime

Swap Environments URLs (CNAMEs)

It usually takes 2-3 minutes to swap

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Management

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Application versions

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Monitoring

Health CheckEC2 Instance

TCP:80 for nonlegacy containers

HTTP:80 for legacy containers

Application health check URL

HTTP 200 OK= Health

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Usage

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ProcessesUse Monit to monitor processes

Apache HTTP Server

Apache Tomcat

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Pricing

PricingElastic Beanstalk is free, you only pay for the underlying AWS resources

Single-instance Type

EC2 instance

Load-balancing, Autoscaling Type

EC2 instance(s)

Elastic Load Balancing

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準備好上雲端了嗎? Cloud Ready?

如果程式有⽤用到下列其中⼀一個...

HTTP Session

File System

User Data Storage

File Cache

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對不起！還不能上雲端:-(

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HTTP Session Problem

HTTP Session Problem(1)

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Session table

ABAB

Session table

CDCD

JSESSIONID: CDCD JSESSIONID: ABAB

Server#1 Server#2

User#1 User#2

HTTP Session Problem(2)

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Session table

CDCD

JSESSIONID: ABAB

Server#2Session

table

ABAB

JSESSIONID: CDCD

Server#1

User#1 User#2

Invalid Session for Server#2

Load Balancer uses Round Robin

redirect

Solutions for HTTP Session

改程式的做法

Keep Stateless (use access token)

不改程式的做法

Session Persistence

Sticky Sessions

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(Not working for Auto Scaling)

Sticky Sessions Problem(1)

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Session table

ABAB

Session table

CDCD

JSESSIONID: CDCD JSESSIONID: ABAB

Server#1 Server#2

User#1 User#2

Server Session

Server#1 ABAB

Server#2 CDCD

Load Balancer enables Sticky Sessions

Server Session

Server#1 ABAB

Server#2 CDCD

Sticky Sessions Problem(2)

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Session table

ABAB

JSESSIONID: CDCD JSESSIONID: ABAB

Server#1 Server#2

User#1 User#2

Scale in or Server Failure

Invalid Session for Server#1

Session Persistence

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Shared Session table

ABAB

CDCD

JSESSIONID: CDCD JSESSIONID: ABAB

Server#1 Server#2

User#1 User#2

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Session Managers for Tomcat

PersistentManager (JDBC Based Store)

http://tomcat.apache.org/tomcat-7.0-doc/config/manager.html#Nested_Components

Memcached Session Manager

http://code.google.com/p/memcached-session-manager

Redis Session Manager

https://github.com/jcoleman/tomcat-redis-session-manager

Amazon DynamoDB Session Manager

https://github.com/aws/aws-dynamodb-session-tomcat/

Session Managers for Tomcat

Q. 為什麼不使⽤用DeltaManager或BackupManager呢? (in-memory-replication)

A. EC2不⽀支援multicast與boardcast (不完全⽀支援)

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File System Problem

User Data Storage Problem(1)

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Server#1 Server#2

User#1 User#2

File#1

Upload File#1

File#2

Upload File#2

Solutions for User Data Storage(1)

Use FS for User Data Storage

改程式的做法

透過AWS SDK把檔案的存取改到S3

不改程式的做法

⽤用S3FS或NFS

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使⽤用S3FS需注意的地⽅方流量

上傳: 檔案會先上傳⾄至Server, 在由Server寫⼊入S3

下載: 檔案需先由S3取出到Server, 在回傳給User

負載

無法降低Server負載

安全性

敏感的資料: 避免直接對外

⼀一般資料: 直接把網址對外, 可降低負載與下載流量

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Solutions for File Cache

Use FS for File Cache

改程式的做法

將file cache改存⾄至DB或Cache Clusters

不改程式的做法

?

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可以⽤用S3FS做File Cache嗎?

S3不適合儲存File Cache

Latency

Read-After-Write Consistency

Eventually Consistency (US Standard Region)

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SummaryElastic Beanstalk is PaaS, but you retain full control over the underlying infrastructure

Elastic Beanstalk is Free

For Scalability, you should pay attention to

HTTP Session

File System

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Thanks for your attention:)