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08 / writing

Building AWS Cloud Infrastructure: From Local VPCs to Automated CI/CD Pipelines

1 min read

  • aws
  • cloud
  • ci/cd

Transitioning from local backend development to cloud infrastructure requires shifting perspective from single-instance application logic to networking topology, security perimeters, and automated deployment pipelines.

As a junior developer actively building hands-on AWS competence, here are the key architectural patterns and operational principles learned while setting up production cloud infrastructure:

1. Networking Boundaries: Public vs. Private Subnets

A common beginner anti-pattern is placing compute nodes directly into public subnets with open access rules. In professional architecture:

  • Public Subnets: Reserved strictly for ingress gateways—such as Application Load Balancers (ALBs) or bastion hosts with elastic IPs.
  • Private Subnets: Houses application servers (EC2 instances or container clusters) and databases, ensuring zero direct internet exposure. Traffic egress is controlled via NAT Gateways.

2. Defensive Security Groups & Access Control

Security groups act as stateful firewalls. Key rules enforced during setup:

  • Restrict HTTP/HTTPS traffic (ports 80 and 443) to the Application Load Balancer security group.
  • Restrict SSH access (port 22) exclusively to specific VPN IPs or internal bastion hosts.
  • Never use 0.0.0.0/0 ingress rules on backend application ports or database instances.

3. Automated CI/CD Workflows Over Manual SSH

Deploying code via manual SSH uploads is error-prone. Setting up GitHub Actions pipelines:

  • Runs automated linting and unit test suites on every pull request.
  • Builds Docker image artifacts and securely transfers them to compute instances.
  • Executes zero-downtime container swaps using Nginx reverse proxy routing.

4. Continuous Growth & Openness to Mentorship

Cloud infrastructure is vast, covering IAM policies, infrastructure-as-code (Terraform), and container orchestration. Embracing the learning curve with structured hands-on projects, rigorous security hygiene, and guidance from senior engineers is the fastest path to operational excellence.