Regions and Availability Zones¶

1. Global Infrastructure Overview¶

Cloud providers deliver services through data centers distributed worldwide.

1.1 Infrastructure Hierarchy¶

Global Network
├── Region
│   ├── Availability Zone / Zone
│   │   └── Data Center
│   ├── Availability Zone
│   │   └── Data Center
│   └── Availability Zone
│       └── Data Center
├── Region
│   └── ...
└── Edge Locations (CDN, DNS)

1.2 AWS vs GCP Terminology Comparison¶

Concept	AWS	GCP
Geographic Area	Region	Region
Independent Data Center	Availability Zone (AZ)	Zone
Local Services	Local Zones, Wavelength	-
CDN Edge	Edge Locations	Edge PoPs
Private Connection	Direct Connect	Cloud Interconnect

2. Regions¶

2.1 Definition¶

A region is a geographically separated cloud infrastructure area.

Characteristics: - Each region operates independently - Data replication between regions requires explicit configuration - Most services are provided on a per-region basis

2.2 Major AWS Regions¶

Region Code	Location	Recommended from Korea
ap-northeast-2	Seoul	✅ Most recommended
ap-northeast-1	Tokyo	✅ Alternative
ap-northeast-3	Osaka	Optional
ap-southeast-1	Singapore	Optional
us-east-1	N. Virginia	Global services
us-west-2	Oregon	Cost optimization
eu-west-1	Ireland	European services

# Check current region
aws configure get region

# Set region
aws configure set region ap-northeast-2

# List available regions
aws ec2 describe-regions --output table

2.3 Major GCP Regions¶

Region Code	Location	Recommended from Korea
asia-northeast3	Seoul	✅ Most recommended
asia-northeast1	Tokyo	✅ Alternative
asia-northeast2	Osaka	Optional
asia-southeast1	Singapore	Optional
us-central1	Iowa	Free tier
us-east1	South Carolina	Free tier
europe-west1	Belgium	European services

# Check current region
gcloud config get-value compute/region

# Set region
gcloud config set compute/region asia-northeast3

# List available regions
gcloud compute regions list

3. Availability Zones / Zones¶

3.1 Definition¶

An availability zone is an independent data center group within a region.

Characteristics: - Physically separated locations - Independent power, cooling, and networking - Connected by low-latency, high-speed networks - Failure in one AZ does not affect other AZs

3.2 AWS Availability Zones¶

Seoul Region (ap-northeast-2)
├── ap-northeast-2a
├── ap-northeast-2b
├── ap-northeast-2c
└── ap-northeast-2d

AZ Naming Convention: - Format: {region-code}{zone-letter} - Examples: ap-northeast-2a, us-east-1b

# List availability zones
aws ec2 describe-availability-zones --region ap-northeast-2

# Example output
{
    "AvailabilityZones": [
        {
            "ZoneName": "ap-northeast-2a",
            "State": "available",
            "ZoneType": "availability-zone"
        },
        ...
    ]
}

3.3 GCP Zones¶

Seoul Region (asia-northeast3)
├── asia-northeast3-a
├── asia-northeast3-b
└── asia-northeast3-c

Zone Naming Convention: - Format: {region-code}-{zone-letter} - Examples: asia-northeast3-a, us-central1-f

# List zones
gcloud compute zones list --filter="region:asia-northeast3"

# Example output
NAME                 REGION           STATUS
asia-northeast3-a    asia-northeast3  UP
asia-northeast3-b    asia-northeast3  UP
asia-northeast3-c    asia-northeast3  UP

4. Multi-AZ Architecture¶

4.1 High Availability Design¶

┌────────────────────────────────────────────────────────────┐
│                     Region                                  │
│  ┌──────────────────┐    ┌──────────────────┐             │
│  │    AZ-a          │    │    AZ-b          │             │
│  │  ┌────────────┐  │    │  ┌────────────┐  │             │
│  │  │   Web-1    │  │    │  │   Web-2    │  │             │
│  │  └────────────┘  │    │  └────────────┘  │             │
│  │  ┌────────────┐  │    │  ┌────────────┐  │             │
│  │  │   App-1    │  │    │  │   App-2    │  │             │
│  │  └────────────┘  │    │  └────────────┘  │             │
│  │  ┌────────────┐  │    │  ┌────────────┐  │             │
│  │  │ DB-Primary │ │───▶│  │ DB-Standby │  │  (Sync Repl) │
│  │  └────────────┘  │    │  └────────────┘  │             │
│  └──────────────────┘    └──────────────────┘             │
│                                                            │
│  ┌──────────────────────────────────────────┐             │
│  │        Load Balancer (Region-scope)       │             │
│  └──────────────────────────────────────────┘             │
└────────────────────────────────────────────────────────────┘

4.2 Multi-AZ Options by Service¶

AWS:

Service	Multi-AZ Method
EC2	Distribute with Auto Scaling Group
RDS	Enable Multi-AZ option
ElastiCache	Place replica in different AZ
ELB	Automatic Multi-AZ
S3	Automatic Multi-AZ replication

GCP:

Service	Multi-Zone Method
Compute Engine	Distribute with Instance Group
Cloud SQL	Enable high availability option
Memorystore	Place replica in different Zone
Cloud Load Balancing	Automatic Multi-Zone
Cloud Storage	Use Regional class

5. Region Selection Criteria¶

5.1 Key Considerations¶

Criterion	Description	Recommendation
Latency	Physical distance to users	Region near users
Compliance	Data residency requirements	Check legal requirements
Service Availability	Not all services in all regions	Check required services
Cost	Price differences by region	Compare costs
Disaster Recovery	DR site distance	Sufficiently distant region

5.2 Latency Testing¶

AWS Latency Measurement:

# Use CloudPing site
# https://www.cloudping.info/

# Or direct ping test
ping ec2.ap-northeast-2.amazonaws.com
ping ec2.ap-northeast-1.amazonaws.com

GCP Latency Measurement:

# GCP Ping test site
# https://gcping.com/

# Or direct measurement
ping asia-northeast3-run.googleapis.com

5.3 Check Service Availability¶

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

GCP: - https://cloud.google.com/about/locations

5.4 Cost Comparison (EC2/Compute Engine Example)¶

Instance Type	Seoul (AWS)	Virginia (AWS)	Seoul (GCP)	Iowa (GCP)
General 2vCPU/8GB	~$0.10/hour \| ~$0.08/hour	~$0.09/hour \| ~$0.07/hour

Prices may vary, check official pricing

6. Global/Regional/Zonal Services¶

6.1 AWS Service Scope¶

Scope	Service Examples
Global	IAM, Route 53, CloudFront, WAF
Regional	VPC, S3, Lambda, RDS, EC2 (AMI)
Availability Zone	EC2 instances, EBS volumes, Subnets

6.2 GCP Service Scope¶

Scope	Service Examples
Global	Cloud IAM, Cloud DNS, Cloud CDN, VPC (network)
Regional	Cloud Storage (Regional), Cloud SQL, Cloud Run
Zonal	Compute Engine, Persistent Disk

GCP VPC Distinction: - GCP VPC is a global resource (AWS VPC is regional) - Subnets are regional scope

AWS VPC vs GCP VPC

AWS:
├── VPC (Regional) ─── us-east-1
│   ├── Subnet-a (AZ scope) ─── us-east-1a
│   └── Subnet-b (AZ scope) ─── us-east-1b
└── VPC (Separate region) ─── ap-northeast-2
    └── Subnet-a ─── ap-northeast-2a

GCP:
└── VPC (Global)
    ├── Subnet-us (Regional) ─── us-central1
    ├── Subnet-asia (Regional) ─── asia-northeast3
    └── Subnet-eu (Regional) ─── europe-west1

7. Edge Locations¶

7.1 CDN Edge¶

AWS CloudFront: - 400+ edge locations - Static content caching - DDoS protection (AWS Shield)

GCP Cloud CDN: - Leverages Google's global edge network - Automatic SSL/TLS - Cloud Armor integration

7.2 DNS Edge¶

AWS Route 53: - Global Anycast DNS - Latency-based routing - Geolocation routing

GCP Cloud DNS: - Global Anycast - 100% availability SLA - DNSSEC support

8. Disaster Recovery Strategy¶

8.1 DR Patterns¶

Pattern	RTO	RPO	Cost	Description
Backup & Restore	Hours~Days	Hours~Days	Low	Only backups stored in different region
Pilot Light	Minutes~Hours	Minutes~Hours	Medium	Only core systems on standby
Warm Standby	Minutes	Minutes	High	Scaled-down environment always running
Active-Active	Seconds	Near 0	Very High	All regions running simultaneously

8.2 Cross-Region Replication¶

AWS S3 Cross-Region Replication:

# Configure S3 bucket replication
aws s3api put-bucket-replication \
    --bucket source-bucket \
    --replication-configuration '{
        "Role": "arn:aws:iam::account-id:role/replication-role",
        "Rules": [{
            "Status": "Enabled",
            "Destination": {
                "Bucket": "arn:aws:s3:::destination-bucket"
            }
        }]
    }'

GCP Cloud Storage Replication:

# Use Dual-region or Multi-region bucket
gsutil mb -l asia gs://my-multi-region-bucket

# Or replicate with Storage Transfer Service
gcloud transfer jobs create \
    gs://source-bucket gs://destination-bucket

9. Practice: Query Region/AZ Information¶

9.1 AWS CLI Practice¶

# 1. List all regions
aws ec2 describe-regions --query 'Regions[*].RegionName' --output text

# 2. List AZs in Seoul region
aws ec2 describe-availability-zones \
    --region ap-northeast-2 \
    --query 'AvailabilityZones[*].[ZoneName,State]' \
    --output table

# 3. Check service availability by region (SSM parameter)
aws ssm get-parameters-by-path \
    --path /aws/service/global-infrastructure/regions \
    --query 'Parameters[*].Name'

9.2 GCP gcloud Practice¶

# 1. List all regions
gcloud compute regions list --format="value(name)"

# 2. List Zones in Seoul region
gcloud compute zones list \
    --filter="region:asia-northeast3" \
    --format="table(name,status)"

# 3. Check machine types in specific region
gcloud compute machine-types list \
    --filter="zone:asia-northeast3-a" \
    --limit=10

10. Next Steps¶

04_Virtual_Machines.md - Virtual machine creation and management
09_Virtual_Private_Cloud.md - VPC networking