switching software/cloud infrastructure

DigitalOcean to AWS: SME Cloud Migration Guide

Move from DigitalOcean droplets to AWS EC2 with zero downtime for UK startups.

1. Executive Summary

This guide outlines the strategic migration of infrastructure from DigitalOcean (DO) to AWS (London Region: eu-west-2). While DigitalOcean excels in simplicity and predictable pricing for SMBs, AWS offers a hyper-scale ecosystem, advanced security primitives, and managed services (RDS, EKS, Lambda) that facilitate enterprise-grade scalability. This migration requires a transition from DO’s flat, provider-managed networking to AWS’s software-defined Virtual Private Cloud (VPC) architecture.

2. Why Businesses Migrate

Drivers:

  • Operational Maturity: Moving from manual Droplet management to Infrastructure as Code (Terraform/CDK).
  • Service Breadth: Access to specialized services like AWS Global Accelerator, AWS WAF, and complex Managed Kubernetes (EKS).
  • Compliance/Audit: Meeting stringent UK financial or healthcare regulatory frameworks.

Anti-patterns:

  • "Lift and Shift" without optimization: Moving monolithic applications without utilizing AWS Auto Scaling or managed databases.
  • Ignoring Egress Costs: Failing to account for data transfer out (DTO) charges, which are more granular in AWS than DO’s inclusive bandwidth model.

3. The 6 Rs of Cloud Migration (DO to AWS Context)

  • Rehost (Lift & Shift): Moving DO Droplets to EC2 instances using AWS Application Migration Service (MGN). Best for legacy monoliths.
  • Replatform (Lift & Reshape): Migrating from self-hosted databases on Droplets to Amazon RDS (e.g., MySQL on Droplet to RDS MySQL).
  • Refactor: Migrating from application servers to AWS Lambda or Fargate/EKS to leverage serverless benefits.
  • Retain: Keeping specific workloads on DO if they have low latency requirements or are non-critical.
  • Retire: Decommissioning shadow IT or redundant services discovered during assessment.
  • Repurchase: Switching from self-managed software (e.g., self-hosted Redis) to SaaS or AWS Marketplace equivalents (e.g., ElastiCache).

4. Pre-Migration Assessment

  • Inventory: Use tools like AWS Application Discovery Service to map dependencies. Document DO Droplet CPU/RAM/IOPS.
  • Network Mapping: DO uses a simplified private network. AWS requires designing a VPC with public/private subnets, NAT Gateways, and Route Tables.
  • IAM: DO IAM is project-based and simple. AWS IAM is granular; implement Least Privilege using IAM Roles and Policies rather than long-lived user credentials.
  • Data Transfer Calc: Assess bandwidth requirements. Utilize AWS Snowball for massive datasets or rsync/AWS DataSync for continuous synchronization of file systems.

5. Step-by-Step Execution Plan

  1. Pilot: Deploy a non-production stack (VPC, Security Groups, EC2) to test connectivity.
  2. Foundation: Establish AWS Landing Zone/Control Tower in eu-west-2. Set up AWS Organizations and SCPs for governance.
  3. Data Migration:
    • Databases: Use AWS Database Migration Service (DMS) for continuous replication.
    • Storage: Use AWS DataSync to move content from DO Spaces to S3.
  4. Cutover: Implement DNS cutover via Route 53. Use a weighted routing policy to shift traffic gradually from DO to AWS.

6. Troubleshooting Common Issues

  • Connectivity: DO Droplets often rely on simple firewall rules (UFW/Iptables). AWS requires Security Groups (stateful) and Network ACLs (stateless). Ensure these are configured to allow cross-environment traffic during the cutover window.
  • Performance: IOPS throttling on smaller EC2 instances compared to DO’s premium SSDs. Use Provisioned IOPS (io2) if required.
  • IAM Latency: Ensure cross-account roles are correctly scoped, as broad "Admin" permissions often hide misconfigured service-to-service communication.

7. UK-Specific Compliance

  • Data Residency: Ensure all data stays within the eu-west-2 (London) region. Use AWS Config rules to prevent the deployment of resources in non-UK regions.
  • GDPR: Leverage AWS’s Data Processing Addendum (DPA). Ensure encryption at rest (KMS) and in transit (TLS 1.2+) is enforced to meet UK Information Commissioner’s Office (ICO) standards.

8. Cost Modeling

  • DO Model: Flat pricing (Compute + Bandwidth included).
  • AWS Model: Pay-per-use. Compute, Egress, IOPS, API Requests, and Managed Service overhead.
  • Optimization: Use AWS Compute Optimizer to right-size instances. Utilize Savings Plans or Reserved Instances for predictable, long-running workloads to reduce costs by up to 72% compared to On-Demand.

9. Conclusion

Migrating from DigitalOcean to AWS is a transition from a simplified hosting environment to a complex, feature-rich ecosystem. By focusing on Replatforming (RDS) and Refactoring (EKS/Lambda) early, organizations can offset the increased operational complexity with significantly higher performance, security, and scalability in the UK market.