Cloud Migration Planning Guide

Help me create a comprehensive cloud migration plan with the following details:

Current Environment: [ON-PREMISES/COLOCATION/OTHER CLOUD]
Target Cloud Provider: [AWS/GCP/AZURE]
Applications to Migrate: [LIST KEY APPLICATIONS]
Data Volume: [APPROXIMATE DATA SIZE]
Compliance Requirements: [LIST REGULATIONS]
Migration Timeline: [DESIRED TIMEFRAME]
Budget for Migration: [BUDGET RANGE]

Develop a migration plan across these six phases:

1. Discovery and Assessment
- Inventory all applications, databases, and infrastructure components. Map application dependencies using tools like AWS Application Discovery Service or Azure Migrate. Classify each workload by complexity including simple, moderate, and complex. Assess application architectures for cloud readiness and identify blockers such as hardware dependencies, licensing restrictions, and legacy protocols. Document current performance baselines for CPU, memory, network, and storage IOPS. Identify data sensitivity classifications and regulatory constraints for each workload.

2. Migration Strategy Selection
- Apply the 7 Rs framework to each workload. Evaluate Rehost for lift-and-shift candidates with minimal changes. Assess Replatform opportunities for managed service adoption such as moving from self-managed MySQL to RDS. Identify Refactor candidates where application modernization delivers significant benefits. Determine which applications to Repurchase with SaaS alternatives. Flag workloads to Retire or Retain on premises. Provide a decision matrix with criteria for selecting the right strategy per workload.

3. Landing Zone and Foundation
- Design the target cloud account and subscription structure. Set up networking including VPC, subnets, route tables, and connectivity back to on-premises via Direct Connect or ExpressRoute. Implement identity federation and IAM policies. Deploy security baselines including encryption, logging, and compliance controls. Configure monitoring, alerting, and operational tooling. Establish CI/CD pipelines for infrastructure deployment.

4. Migration Execution
- Create a wave-based migration plan grouping related applications. Define migration runbooks for each workload type. Plan database migration using DMS, native replication, or export and import approaches. Specify cutover procedures including DNS changes, traffic shifting, and rollback triggers. Design testing protocols for functional validation, performance testing, and security verification. Establish communication plans for stakeholders during each wave.

5. Optimization and Modernization
- Right-size compute resources based on actual utilization data after migration. Implement auto-scaling policies and reserved capacity commitments. Migrate to managed services where beneficial such as containers, serverless, and managed databases. Optimize storage tiers and lifecycle policies. Tune network configurations and implement CDN caching. Establish ongoing cost optimization reviews.

6. Operational Readiness and Handover
- Train operations teams on cloud-native tools and procedures. Create and test disaster recovery and backup procedures. Document architecture decisions and runbooks. Establish SLAs and monitoring dashboards. Plan for decommissioning legacy infrastructure. Set up continuous improvement processes and cloud center of excellence.

For each phase, provide a timeline estimate, key milestones, risk factors with mitigations, tool recommendations, team roles and responsibilities, and success criteria.