Cloud Migration

Cloud Migration

Estimated time: 2-6 months

Cloud migration is a strategic undertaking that, when done well, delivers agility, scalability, and cost efficiency. When done poorly, it creates expensive, hard-to-manage cloud infrastructure that costs more than the on-premises systems it replaced. This workflow provides a structured approach: assess what you have, plan how to migrate it, execute the migration in waves, optimize for cloud-native benefits, and establish governance for ongoing management.

The workflow uses the industry-standard 6 R's framework for categorizing migration strategies: Rehost (lift-and-shift), Replatform (lift-and-reshape), Refactor (re-architect for cloud-native), Repurchase (replace with SaaS), Retire (decommission), and Retain (keep on-premises). Each application gets the migration strategy that matches its business value and technical complexity.

When to Use

• User wants to cloud migration
• User needs a structured, step-by-step process for cloud migration
• User wants to migrate to the cloud
• I need to move from on-prem to AWS
• How do I plan a cloud migration
• Do NOT use when: the request is outside the scope of cloud migration or requires professional advice beyond educational guidance
• Do NOT use for single-step tasks that one atomic skill can handle independently

Prerequisites

Before starting this workflow, ensure:

• Executive sponsorship and budget allocation for migration
• Inventory of applications and infrastructure to migrate
• Cloud provider account (AWS, Azure, or GCP)
• Network connectivity between on-premises and cloud (VPN or Direct Connect)
• Team with cloud skills (or training plan)
• Business continuity requirements (acceptable downtime per application)

Steps

Step 1: Assess Current State (uses: risk-assessor)

identify migration risks and the AWS Architect skill (or equivalent for your target cloud) to assess cloud readiness. Catalog every application: technology stack, dependencies, data volume, traffic patterns, compliance requirements, and business criticality. Map the dependency graph: which applications depend on which databases, APIs, and shared services. Calculate current total cost of ownership (TCO) for baseline comparison. Identify high-risk applications (stateful, tightly coupled, legacy technology) that need special attention.

• Input: Current infrastructure inventory (servers, databases, storage), Application portfolio, Network topology
• Output: Application portfolio catalog (technology, dependencies, criticality), Dependency map (application-to-infrastructure, app-to-app), Current TCO baseline
• Key focus: Use the Risk Assessor skill to identify migration risks and the AWS Architect skill (or equivalent for your target cloud) to assess cloud readiness

Step 2: Plan Migration Waves (uses: aws-architect)

classify each application using the 6 R's framework: Rehost, Replatform, Refactor, Repurchase, Retire, or Retain. Then organize applications into migration waves (batches of 3-7 applications migrated together). Wave 1 should be low-risk, non-critical applications to build team confidence and validate the migration process. Subsequent waves increase in complexity and criticality. Create a detailed plan for each wave: migration strategy, timeline, rollback procedure, success criteria, and team assignments.

• Input: Assessment from Step 1, Business priorities and timelines, Team capacity and cloud expertise
• Output: 6 R's classification for every application, Migration wave plan (applications per wave, with sequence), Detailed migration plan per wave (strategy, timeline, rollback)
• Key focus: Use the AWS Architect skill to classify each application using the 6 R's framework: Rehost, Replatform, Refactor, Repurchase, Retire, or Retain

Step 3: Set Up Cloud Foundation (uses: terraform-engineer)

build the cloud foundation as code: account structure (multi-account for production, staging, shared services), networking (VPC, subnets, security groups, VPN/Direct Connect to on-premises), IAM (roles, policies, SSO), and shared services (logging, monitoring, DNS). Use the Security Hardener skill to apply cloud security best practices from day one: CIS benchmarks, encryption defaults, IAM least privilege, and audit logging. This foundation must be solid before any application migration begins.

• Input: Target cloud architecture from Step 2, Security and compliance requirements, Network connectivity requirements
• Output: Account/subscription structure, Network architecture (VPC, subnets, routing, connectivity), IAM configuration (roles, policies, SSO integration)
• Key focus: Use the Terraform Engineer skill to build the cloud foundation as code: account structure (multi-account for production, staging, shared services), networking (VPC, subnets, security groups, VPN/Direct Connect to on-premises), IAM (roles, policies, SSO), and shared services (logging, monitoring, DNS)

Step 4: Migrate Wave 1 (Validation Wave) (uses: docker-engineer)

containerize applications if replatforming. Use the Database Architect skill to plan database migration strategies (schema migration, data transfer, replication cutover). Use the Data Migration Specialist skill for zero-downtime data migration where required. Execute the migration: provision cloud infrastructure, migrate data, deploy application, validate functionality, switch traffic (DNS cutover or load balancer switch), and monitor. Keep the on-premises environment running as a rollback target for at least 2 weeks after cutover.

• Input: Wave 1 applications (low-risk, non-critical), Cloud foundation from Step 3, Migration strategy per application (rehost, replatform, etc.)
• Output: Migrated Wave 1 applications in cloud, Database migration scripts and verification reports, Cutover runbooks (step-by-step procedure)
• Key focus: Use the Docker Engineer skill to containerize applications if replatforming

Step 5: Monitor and Optimize (uses: monitoring-engineer)

set up cloud-native monitoring for migrated applications. Compare performance metrics against the on-premises baseline. Use the Cloud Cost Optimizer skill to identify optimization opportunities: right-size instances, implement auto-scaling, convert to reserved instances for stable workloads, use spot instances for batch processing, and clean up unused resources. Cloud costs in the first month are often 2-3x the steady-state cost due to over-provisioning -- optimization brings costs down to target.

• Input: Migrated applications from Step 4, SLIs/SLOs for migrated services, Cloud cost data
• Output: Cloud monitoring dashboards for migrated applications, Performance comparison report (cloud vs on-premises), Cost optimization report with recommendations
• Key focus: Use the Monitoring Engineer skill to set up cloud-native monitoring for migrated applications

Step 6: Migrate Remaining Waves (uses: aws-architect)

Execute remaining migration waves, applying lessons learned from Wave 1. Each wave should be faster than the previous one as the team builds expertise and reuses infrastructure patterns. For applications classified as Refactor, design cloud-native deployments. For applications classified as Retire or Repurchase, coordinate decommission with the SaaS replacement timeline. Track progress against the overall migration plan and adjust wave composition as needed.

• Input: Lessons learned from Wave 1, Remaining migration waves from Step 2, Refined processes and tooling
• Output: Migrated applications per wave, Migration progress dashboard, Updated cost comparison (cloud vs on-premises)
• Key focus: Execute remaining migration waves, applying lessons learned from Wave 1

Step 7: Establish Cloud Governance (uses: cloud-cost-optimizer)

establish ongoing cost governance: budget alerts, cost allocation tags, monthly cost review process, and anomaly detection. Use the Security Hardener skill to establish security governance: automated compliance scanning, security baseline enforcement, IAM review cadence, and incident response procedures for cloud. Create guardrails (Service Control Policies, landing zone rules) that prevent common mistakes without blocking development.

• Input: Fully migrated cloud environment, Ongoing cost management requirements, Compliance and security requirements
• Output: Cost governance framework (budgets, alerts, review process), Cost allocation tagging strategy, Security governance framework (scanning, compliance, review)
• Key focus: Use the Cloud Cost Optimizer skill to establish ongoing cost governance: budget alerts, cost allocation tags, monthly cost review process, and anomaly detection