Ch3 Elasticity and Scalability Concepts Technical requirements Sources of failure Dividing and conquering Virtualization technologies LAMP installation Scaling the webserver Resiliency EC2 persistence model Disaster recovery Cascading deletion Bootstrapping Scaling the compute layer Scaling a database server Summary Further reading

1. Study Group: AWS SAA Guide
Chapter 03 -
Elasticity and Scalability Concepts
Aki Yu
2020.Apr

2. ● AWS Certified Solutions Architect - Associate Guide
https://www.amazon.com/AWS-Certified-Solutions-Architect-certification/dp/1789130662/
● Google Books 上可讀到前3章:
https://books.google.com.tw/books?id=P-l1DwAAQBAJ
● PacktPub 與 Oreilly 各有 10 Days Free Trial 可看書的完整內容:
https://www.packtpub.com/virtualization-and-cloud/aws-certified-solution-architect-associate-guide
https://www.oreilly.com/library/view/aws-certified-solutions/9781789130669/
● 本書 Github Source Code:
https://github.com/PacktPublishing/AWS-Certified-Solutions-Architect-Associate-Guide
https://github.com/gabanox/Certified-Solution-Architect-Associate-Guide
Book: AWS SAA Guide

3. Ch3 Elasticity and Scalability Concepts
• Technical requirements
• Sources of failure
• Dividing and conquering
• Virtualization
technologies
• LAMP installation
• Scaling the web server
• Resiliency
• EC2 persistence model
• Disaster recovery
• Cascading deletion
• Bootstrapping
• Scaling the compute
layer
• Scaling a database
server
• Summary
• Further reading

4. Ch3 Elasticity and Scalability Concepts
AWS Command Line Interface
https://aws.amazon.com/cli/
• Technical requirements
• Sources of failure (S3)
1. No, you're not crazy. Part of the internet broke
2. How a typo took down S3, the backbone of the internet
3. Amazon S3 Outage Has Broken a Large Chunk of the Internet
Root Cause - Typo
Failure should be our teacher;
as Thomas A. Edison said, "I have not failed. I've just found 10,000 ways that won't work."

5. • Dividing and conquering (分而治之)
Recovery Oriented Computing (ROC)
如果您有一個複雜的問題，請將其分解為各個易於管理的部分；
隔離它們，並專注於避免失敗的獨特策略。

6. • Serial configuration RDS
EBS
• Parallel configuration
• Active-Active (AA)
• High Availability (HA)
Warm Standby, Hot Standby, Cold

7. • Reactive and proactive scalability
Horizontal scalability
To avoid single points of failure (SPOFs)
Vertical scalability
加ram 加cpu 舉例來說 Elastic Compute Cloud (EC2) has different instance types, families, and sizes, which allows
for the vertical scalability of a single compute node, as shown in the following screenshot:
LAMP
• Exercise

8. • Virtualization technologies
aws ec2 run-instances --image-id {ami-14c5486b}—key-name {BookShelfApp }

9. NETWORK & SECURITY | Security Groups
CLIENT_IP=$(curl -s http://checkip.amazonaws.com)"/32"
aws ec2 authorize-security-group-ingress --group-name default --protocol tcp --port 22 --cidr $CLIENT_IP
LAMP installation
sudo yum update -y
sudo yum install -y httpd24 php70 mysql56-server php70-mysqlnd sudo usermod -a -G apache ec2-user
sudo chown -R ec2-user:apache /var/www
sudo chmod 2775 /var/www
find /var/www -type d -exec sudo chmod 2775 {} ;
find /var/www -type f -exec sudo chmod 0664 {} ;
echo "<?php phpinfo(); ?>" > /var/www/html/phpinfo.php

10. aws ec2 authorize-security-group-ingress --group-id {sg-bddd92cb} --protocol tcp --port 80 --cidr 0.0.0.0/0

11. Scaling the web server
1. Obtain the instance-id with the following expression:
export CURRENT_INSTANCE=$(aws ec2 describe-instances --query 'Reservations[*].Instances[*].InstanceId' --filters
'Name=instance- state-name,Values=running' --output text)
2. We must stop the instance to change the instance-type attribute to m4.large, as follows:
aws ec2 stop-instances --instance-id $CURRENT_INSTANCE --output json
3. Once stopped, modify the attribute via the CLI, as follows:
aws ec2 modify-instance-attribute --instance-id $CURRENT_INSTANCE - -instance-type m4.large
4. Restart the instance, as follows:
aws ec2 start-instances --instance-id $CURRENT_INSTANCE --output json

12. Resiliency
CURRENT_INSTANCE=$(aws ec2 describe-instances --query 'Reservations[*].Instances[*].InstanceId' --filter
'Name=tag:Name,Values=WebServer' --output text)
aws ec2 reboot-instances --instance-ids $CURRENT_INSTANCE
aws ec2 stop-instances --instance-id $CURRENT_INSTANCE
aws ec2 start-instances --instance-id $CURRENT_INSTANCE
aws ec2 allocate-address --domain vpc
IP 會跑掉，所以做一個 ip先
aws ec2 associate-address --allocation-id ｛eipalloc-d300d8db｝ --instance-id $CURRENT_INSTANCE

13. .／lsblk 列出 Block Device
EC2 persistence model
Xen hypervisors using HVM virtualization.
Every EC2 instance has private access to a DNS metadata server within the VPC at the 169.254.169.254 canonical address.
metadata server can be used to read information about the instance itself, along with the surrounding infrastructure in which it is running.
This is valuable when you are writing bootstrapping scripts, applying application configurations, and even performing service
authentication techniques.
With a simple curl command, we can access the block-device-mapping information from this image.
Direct Attached Storage (DAS) / Network Attached Storage (NAS)

14. aws ec2 stop-instances --instance-id $CURRENT_INSTANCE
aws ec2 detach-volume --volume-id {vol-0cae081b840a5d91e}
aws ec2 attach-volume --volume-id vol-0cae081b840a5d91e --instance-id
aws ec2 start-instances --instance-id $CURRENT_INSTANCE --output json
Our file no longer exists.

15. Direct Attached Storage (DAS) / Network Attached Storage (NAS)
1. To properly associate the volume, let's query the AZ in which this instance is currently running, as follows:
aws ec2 describe-instances --instance-ids $CURRENT_INSTANCE -- output json --query
'Reservations[0].Instances[0].Placement'
The result is as follows:
{
"Tenancy": "default", "GroupName": "", "AvailabilityZone": "us-east-1a"
}
2. Create the volume by using the AvailabilityZone information, as follows:
aws ec2 create-volume
--size 80
--availability-zone $(aws ec2 describe-instances --instance-ids $CURRENT_INSTANCE --query
'Reservations[0].Instances[0].Placement.AvailabilityZone' --filter 'Name=tag:Name,Values=WebServer' --output
text)
--volume-type gp2
3. Now, describe the volumes that are available in order to find the status information, as follows:
aws ec2 describe-volumes

16. aws ec2 attach-volume --volume-id $(aws ec2 describe-volumes
-- query 'Volumes[0].VolumeId' --output text)
--instance-id $CURRENT_INSTANCE --device /dev/xvda
sudo mkfs -t ext4 /dev/xvdb
sudo mkdir /data
sudo mount /dev/xvdb /data
vi /etc/fstab

18. Cascading deletion
aws ec2 create-snapshot --volume-id vol-080c266f654bca621 -- description "Data volume first snapshot"
aws ec2 describe-snapshots --owner-ids self
aws ec2 delete-volume --volume-id vol-080c266f654bca621

19. Bootstrapping cloud-init
1. We will provision our new instance by using the following user data input file. You can find this file in the GitHub repository under
chapter02/bootstrap.txt:
aws ec2 run-instances --image-id ami-14c5486b --key-name BookShelfApp --instance-type t2.medium --security-group-ids sg-
bddd92cb --user-data file://bootstrap.txt
2. Refresh the current instance variable, as follows:
export CURRENT_INSTANCE=$(aws ec2 describe-instances --query 'Reservations[*].Instances[*].InstanceId' --filters
'Name=instance- state-name,Values=running' --output text)
3. Now, associate the Elastic IP as follows:
aws ec2 associate-address --allocation-id eipalloc-d300d8db -- instance-id $CURRENT_INSTANCE
4. Navigate to your Elastic IP address by using your web browser (in my case,
it's 52.44.105.242); we can now validate that our web server was created from scratch, as shown in the following screenshot:

21. Scaling the compute layer
aws ec2 run-instances --image-id ami-14c5486b --key-name BookShelfApp
--instance-type t2.large
--security-group-ids sg- bddd92cb
--user-data file://bootstrap.txt
aws ec2 associate-address --instance-id i-096a8c337e10e9edf -- allocation-id eipalloc-d300d8db

22. Proactive scalability
Scaling a database server
Create Read Replica

23. 名詞說明

24. • SRA 計算
serial configuration / parallel configuration
• fstab 開機自動掛載
• Floating IP cloud pattern

25. ● S3 - Simple Storage Service
● RDS - Rational Database Service
● EBS - Elastic Block Store
一般用途 SSD (gp2) 磁碟區 0.10 USD 佈建儲存每月每 GB
佈建 IOPS SSD (io1) 磁碟區 0.125 USD 佈建儲存每月每 GB和 0.065 USD 每月每個佈建 IOPS
輸送量優化 HDD (st1) 磁碟區 0.045 USD 佈建儲存每月每 GB
冷 HDD (sc1) 磁碟區 0.025 USD 佈建儲存每月每 GB
磁帶
● HA● AA

26. ● EC2 - Elastic Compute Cloud
● AMI - Amazon Machine Image
● LAMP - Linux、Apache、MySQL、PHP
● PV - ParaVirtualization
● HVM - Hardware Virtual Machine
● Xen hypervisor