How to Migrate from AWS to Bare Metal Without Downtime

A practical migration playbook for UK engineering teams looking to repatriate workloads from AWS EC2 to dedicated bare metal infrastructure — with zero downtime, lower latency, and 50%+ cost savings.

Why Migrate from AWS to Bare Metal?

For many UK businesses, AWS started as the obvious choice. Fast provisioning, global reach, and an endless menu of services. But as your infrastructure scales, the cost picture changes dramatically. That £500/month EC2 bill quietly becomes £5,000 once you factor in data transfer, NAT gateways, load balancers, and reserved instances you forgot to turn off.

UK companies are increasingly turning to bare metal repatriation — moving workloads from virtualised cloud instances back to dedicated physical hardware. The results speak for themselves:

• 50-65% cost reduction on equivalent compute capacity
• 10-30% lower latency for UK users with local data centres
• Predictable performance — no noisy neighbours, no CPU credits
• Full data residency for GDPR compliance without complex configurations
• Simplified pricing — one monthly bill, no surprise charges

The Migration Framework: 6 Phases

We've developed this framework based on our experience helping UK companies repatriate from AWS. Each phase is designed to be reversible — you can roll back at any point without impact on production traffic.

Phase 1: Discovery & Assessment (Week 1-2)

Begin by mapping your entire AWS footprint. Too many migration attempts fail because teams discover orphaned dependencies halfway through. Use the AWS Resource Explorer and Cost Explorer to build a complete inventory:

• List all EC2 instances, RDS databases, ElastiCache clusters, and load balancers
• Map inter-service dependencies and data flow
• Identify which workloads are suitable for bare metal (compute-heavy, predictable throughput) vs which might stay on cloud (auto-scaling web tiers, serverless functions)
• Calculate total cost of ownership over 3 years — include data transfer, support plans, and reserved instance commitments

Phase 2: Design Target Architecture (Week 2-3)

Design your bare metal architecture. Modern bare metal hosting isn't like the unmanaged servers of 2015 — you get KVM-based virtualisation, API-driven provisioning, and software-defined networking on top of dedicated hardware.

Your target architecture should include:

• Compute: Dedicated servers with NVMe storage, partitioned into KVM VPS instances if needed
• Networking: VLAN segmentation, BGP sessions, and firewall rules
• Storage: ZFS-based storage pools with snapshots and replication
• Backup: Off-site backups to a separate data centre or object storage
• Monitoring: Prometheus + Grafana for observability (replaces CloudWatch)

Phase 3: Set Up Bare Metal Environment (Week 3-4)

Provision your bare metal infrastructure in parallel with your existing AWS environment. This phase has zero customer impact — you're building the landing zone before you move anything.

Key steps:

1. Provision dedicated servers in your chosen UK data centre
2. Configure KVM hosts and create VPS instances matching your EC2 profiles
3. Set up networking: VLANs, firewalls, and VPN tunnels between AWS and your new environment
4. Deploy monitoring stack (Prometheus + Grafana) alongside your existing CloudWatch setup
5. Configure backup pipelines and test restore procedures

Phase 4: Database Migration (Week 4-5)

Database migration is the most critical phase. Use a replication-based approach for zero downtime:

• Set up PostgreSQL streaming replication or MySQL Group Replication from AWS RDS to your bare metal database server
• Use a read replica on the target to validate data consistency before switching
• Configure replication lag monitoring — alert if lag exceeds 5 seconds
• Run application integration tests against the replica to verify compatibility

Phase 5: Application Migration (Week 5-6)

With database replication running, migrate application workloads using a blue-green deployment strategy:

1. Deploy application code to the bare metal environment behind a private load balancer
2. Validate health checks, logging, and monitoring in the new environment
3. Run a canary test — route 5% of traffic through a DNS-weighted record or reverse proxy
4. Monitor error rates, latency, and resource usage for 24-48 hours
5. Gradually increase traffic weight: 25% → 50% → 75% → 100%
6. Keep AWS environment running for 72 hours post-migration as rollback insurance

Phase 6: Decommissioning & Optimisation (Week 6-8)

Once you've validated stability:

• Decommission AWS resources systematically — start with non-production, then staging, then production
• Cancel reserved instances and support plans
• Set up infrastructure-as-code for your new environment (Terraform, Ansible)
• Optimise bare metal resource allocation based on real usage patterns
• Document the new architecture and runbooks for your team

Cost Comparison: AWS vs Bare Metal

Here's a real-world comparison based on a typical UK SaaS company running 10 application servers, 3 database servers, and supporting infrastructure:

Component	AWS (Monthly)	Bare Metal (Monthly)	Savings
10 x EC2 (m6i.large)	£2,200	£1,200	45%
3 x RDS (db.r6g.large)	£1,800	£900	50%
Data Transfer (2 TB/mo)	£400	£0 (included)	100%
NAT Gateway + ALB	£180	£0 (included)	100%
CloudWatch + Support	£220	£50 (self-hosted)	77%
Total	£4,800	£2,150	55%

Common Challenges & Solutions

Auto-scaling

Bare metal doesn't offer the instant auto-scaling of AWS. Solution: design for predictable workloads and use buffer capacity. Most UK SaaS companies find their traffic is 80% predictable — you size for that baseline and handle peaks with a small cloud burst capability if needed.

Managed Services

RDS, ElastiCache, and SQS don't have direct bare metal equivalents. Solution: use self-managed PostgreSQL/MySQL, Redis, and RabbitMQ on your bare metal servers. These run faster on dedicated hardware and give you full control over configuration.

Compliance

Many UK fintech and healthcare companies find bare metal easier for compliance because data never leaves the UK and you control the full hardware stack. No shared tenancy concerns for PCI DSS or ISO 27001.

Migration Tools & Scripts

To make your migration smoother, here are essential tools:

• pglogical / mysql-binlog — database replication from RDS to bare metal
• rsync + Lsyncd — file synchronisation for static assets
• HAProxy / Nginx — traffic splitting for blue-green deployment
• Prometheus + node_exporter — infrastructure monitoring (CloudWatch equivalent)
• Ansible / Terraform — infrastructure-as-code for reproducible deployments

Related reading: Cloud Exit Strategy: Complete Guide • How to Migrate Your Business to Bare Metal • Hostingowy vs AWS