Cloud Architecture Designs

A small collection of cloud architecture designs I have built or would build, kept here as a learning journey from a 2022 classic 3-tier to a 2026 hybrid reference architecture.

Featured: Hybrid Cloud Reference (2026)

A reference architecture connecting an on-premises Microsoft 365 estate to a modern AWS landing zone. Models the kind of environment I operate today (HPE/Dell servers, M365, Cisco network) and how I would extend it into the cloud.

flowchart LR
  subgraph Onprem["On-Premises · Seoul"]
    HPE["HPE / Dell<br/>VMware ESXi"]
    AD["Active Directory"]
    HPE --- AD
  end

  subgraph M365["Microsoft 365"]
    ENTRA["Entra ID"]
    INTUNE["Intune + Defender"]
  end

  subgraph AWS["AWS · ap-northeast-2"]
    direction TB
    EDGE["Route 53 → CloudFront<br/>WAF + Shield"]
    ALB["ALB"]
    ECS["ECS Fargate"]
    DB["Aurora Serverless v2"]
    EDGE --> ALB --> ECS --> DB
    SEC["GuardDuty · Security Hub<br/>CloudTrail Lake · Config"]
    OBS["CloudWatch · X-Ray<br/>Managed Prometheus + Grafana"]
    IAC["Terraform + GitHub Actions<br/>OIDC Federation"]
  end

  AD <-->|"Entra Connect"| ENTRA
  Onprem <-->|"Direct Connect / VPN"| AWS
  ENTRA <-->|"SAML / OIDC<br/>IAM Identity Center"| AWS

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See designs/02-hybrid-cloud-2026/ for:

• Full architecture write-up with identity, connectivity, security, and delivery layers
• Editable architecture.drawio source (open in diagrams.net)
• Disaster recovery tiering and cost guardrails

Earlier work

01 -- Classic 3-Tier (2022)

A traditional 3-tier AWS architecture from 2022: ALB → EC2 web tier → NLB → WAS in private subnets, with Bastion host, Client VPN, CloudTrail, and CodePipeline. Kept as a learning baseline.

The README in that folder includes a side-by-side comparison of what I would change in 2026 (Fargate instead of EC2, GitHub Actions instead of CodeCommit, Session Manager instead of Bastion host, etc.).

How to view the diagrams

Format	How to view
Mermaid (this README)	Renders inline on GitHub automatically
.drawio	Open in diagrams.net (web, free) or download draw.io desktop
.png	Renders inline in any markdown viewer

To export a .drawio file to PNG: open in diagrams.net → File → Export As → PNG.

Author

Byeongki "Ki" Cho -- bilingual cloud and infrastructure engineer in Seoul. LinkedIn