Cloud migration: When, why, and how?

Cloud migration is the process by which companies move servers, data, applications, and IT resources from their own data center or hosting to a cloud environment. This can happen completely or gradually, for example, to a public, private, or hybrid cloud.

It is important to note that cloud migration is not just about technology. It is about structuring operations, security, costs, and responsibility in such a way that your systems run reliably and can be further developed.

For whom does cloud migration make sense, and when does it not?

Cloud migration makes sense if you need more scalability, better operational reliability, and faster implementation without operations and costs getting out of hand.

1. Hardware, operating systems, or databases reach end-of-life
2. Releases are slow or risky, deployments are rare or costly
3. Peak loads lead to bottlenecks or expensive oversizing
4. Security patches, backups, and restore tests are not clearly verifiable
5. Operations depend on individual persons or know-how is insufficiently documented
6. Interfaces are fragile, changes often cause side effects
7. There is a lack of transparency; you only have a rough idea of costs and utilization
8. New digital services fail due to infrastructure limitations

Why move to the cloud?

Many teams don’t move to the cloud because they want new technology. They move because everyday life consumes too much energy: releases take too long, disruptions are difficult to explain, security issues remain unresolved, and every change feels risky. Cloud migration can reduce these very costs if you clarify standards and responsibilities before implementation.

Cloud migration can support technical and business goals at the same time. The most important benefits can be clearly measured:

• Scaling: Cost per transaction, utilization
• Operational reliability: RTO, RPO, restore tests
• Speed: Deployment frequency, lead time
• Security: findings, patch time, audit trails
• Costcontrol: Tagging rate, budget alerts

The following steps are deliberately formulated in such a way that you know exactly what will be achieved at the end of each phase.

The 9 steps of cloud migration

1. Clarify goals and scope
   Content: Business goals, systems in focus, performance measurement, delimitation
   Result: Target vision, scope list, success criteria, priorities
2. Perform an analysis of the currentsituation
   Content: Applications, data, dependencies, operation, security, costs, risks
   Result: Workload inventory, dependency overview, risk list, cost breakdown
3. Define target architecture
   Content: Target model, network, identity, security, operating model
   Result: Target architecture, role model, security standards, operating framework
4. Define migration strategy for each workload
   Content: Rehost, replatform, refactor, replace, retire, retain
   Result: Strategy decision per system, justification, effort and risk assessment
5. Build landing zone
   Contents: Accounts, policies, logging, monitoring, backup, IaC, standards
   Result: Standardized basis, governance rules, basic observability setup
6. Implement pilot migration
   Content: 1 to 2 workloads, tests, lessons learned, playbooks, and templates
   Result: Validated standards, test concept, cutover and rollback procedure, implementation modules
7. Perform migration in waves
   Content: Prioritization according to business impact, risk, and dependencies
   Result: Migration plan in waves, acceptance criteria, clear sequence
8. Stabilize and secure operations
   Content: Observability, incident processes, runbooks, cost control, SLAs
   Result: Operational concept, runbooks, alerting, escalation paths, handover to regular operations
9. Optimize
   Content: Performance, security hardening, cost optimization, automation
   Result: Optimization backlog , continuous improvement

What cloud migration strategies are available?

• Rehost: Migration without major changes, fast, but not always optimal in terms of costs and architecture
• Replatform: minor adjustments, better cloud utilization, moderate effort
• Refactor: major changes, most flexible in the long term, but more complex
• Replace: Replacement with standard solution or SaaS
• Retire: System is shut down because it is no longer needed
• Retain: System remains local for the time being, for example due to dependencies or specifications

Security does not come from a single tool. Clear standards, clear responsibilities, and clean implementation are crucial . To achieve this, you need a clean role model for access, consistent least privilege (only as much access as necessary), and MFA (multi-factor authentication). The network is segmented, rules are documented, and connections are secured.

Data and services are encrypted, including key and secret management. Logs and monitoring are centralized, and it is clear who acts on alarms. Backups are defined and restore tests are performed regularly. For compliance, you need data classification, audit trails, and clear documentation.

The 5 most common security mistakes in cloud migration

1. Rights are assigned too broadly
2. Logging is incomplete or not centralized
3. Backups exist, but restore is not tested
4. Secrets are stored incorrectly or insufficiently protected
5. There is a lack of governance, resulting in uncontrolled growth and loss of costs

Cloud costs consist of one-time costs and ongoing costs. “Pay as you go” only helps if governance and cost control are implemented properly.

One-time costs

• Assessment and target architecture
• Landing zone setup and security basics
• Migration and testing
• Adjustments to applications and interfaces

Ongoing costs

• Compute, storage, network, managed services
• Monitoring, logging, backup
• Security services
• Operation, support, further development

Duration briefly classified

The duration almost always depends on dependencies, data volume, and testing effort. Pilot workloads are often realistic in a matter of weeks to a few months, while complex landscapes are migrated in waves.

Typical challenges and how we solve them

1. Dependencies and legacy systems
   Problem: Unclear interfaces and hidden dependencies make migration risky.
   Measures: Dependency analysis, prioritized migration waves, test concept.
   Result: Predictable migration, less risk of failure, clear roadmap.
2. Security and compliance
   Problem: Specifications are in place, but implementation and verification are lacking.
   Measures: Security baseline, role model, logging standards, audit trails, documentation.
   Result: Traceable security, better auditability.
3. Operation andresponsibility
   Problem: Cloud is being introduced, but operation remains unclear.
   Measures: Operating model, incident processes, runbooks, SLAs, monitoring, escalation paths.
   Result: Stable operation, clear responsibilities, less stress in the event of a malfunction.