Cloud migration has become a cornerstone of digital transformation for organisations seeking agility, resilience and competitive advantage. As enterprises increasingly embrace multi-cloud and hybrid environments, understanding the full spectrum of cloud migration, including cloud-to-cloud migration, has never been more important for senior IT leaders. This article explores the essentials of cloud migration, the strategies that work, and the pitfalls to avoid, ensuring your journey to the cloud delivers real business value.
What is cloud migration?
Cloud migration refers to the process of moving digital assets, such as data, applications and IT processes, from on-premises infrastructure to cloud environments, or from one cloud provider to another. While the initial wave of migrations focused on shifting workloads to public clouds, many organisations now face the challenge of cloud-to-cloud migration as they optimise their cloud strategies, seek better pricing, or respond to evolving business needs.
Why organisations migrate to the cloud
The key drivers for cloud migration are diverse but typically include:
Business agility
- Rapid provisioning of new environments
- Ability to launch new products or services quickly
- Streamlined collaboration between distributed teams.
Cost efficiency
- Reduction of capital expenditure (CapEx) on hardware, data centres, and maintenance.
- Shift to operational expenditure (OpEx), paying only for resources used.
- Easier budgeting and forecasting with transparent, usage-based pricing models.
Scalability
- Instantly scale resources up or down to meet fluctuating demand.
- Support for seasonal workloads, such as retail peaks or year-end reporting.
- Avoidance of over-provisioning and under-utilisation of infrastructure.
Resilience and security
- Cloud providers offer robust disaster recovery and backup solutions.
- Built-in redundancy and failover across multiple data centre locations.
- Advanced security features, such as DDoS protection, encryption, and compliance certifications.
Innovation
- Access to emerging technologies like artificial intelligence, machine learning, and advanced analytics.
- Integration with cloud-native services such as IoT, blockchain, and serverless computing.
- Accelerated digital transformation and modernisation of legacy systems.
For many, these benefits are compelling, but realising them requires careful planning and execution.
Types of cloud migration
There are several types of cloud migration, each with its considerations:
On-premises to cloud
Moving applications, data, and infrastructure from traditional data centres to public, private, or hybrid cloud environments.
Often involves rehosting or replatforming legacy workloads.
Requires assessment of application dependencies, data sovereignty, and network connectivity.
Cloud-to-cloud migration
Transferring workloads, data, and applications from one cloud provider to another, such as AWS to Azure, or Google Cloud to AWS.
Motivated by factors like cost optimisation, improved features, regulatory compliance, or avoiding vendor lock-in.
Involves mapping services between providers, managing API compatibility, and ensuring data integrity.
Hybrid and multi-cloud migration
Integrating on-premises infrastructure with multiple cloud platforms for flexibility and resilience.
Enables workload portability, disaster recovery, and avoidance of single-vendor dependency.
Requires robust networking, unified management, and consistent security policies across environments.
Cloud migration strategies
Successful cloud migration hinges on selecting the right approach. The industry often refers to the “6 Rs” of migration:
Rehost (Lift and shift)
- Move applications to the cloud with minimal or no changes.
- Fastest migration method, ideal for legacy systems where speed is a priority.
- May miss out on cloud-native benefits, but reduces risk and complexity.
Replatform
- Make slight modifications to optimise applications for the cloud without significant code changes.
- Examples include switching databases or operating systems to managed cloud services.
- Balances speed and cloud optimisation.
Refactor
- Redesign or re-architect applications to fully leverage cloud-native features and services.
- Enables scalability, resilience, and cost savings, but requires significant investment.
- Suitable for strategic workloads that drive business innovation.
Repurchase
- Replace existing applications with new, cloud-based solutions (e.g., moving from on-premises CRM to SaaS).
- It reduces the maintenance burden and accelerates the adoption of new capabilities.
- May involve retraining staff and adapting business processes.
Retire
- Decommission obsolete or redundant applications that are no longer needed.
- Reduces complexity and ongoing costs.
- Requires thorough analysis to avoid disrupting business operations.
Retain
- Keep some workloads on-premises due to technical limitations, regulatory requirements, or business reasons.
- Enables gradual migration and hybrid cloud strategies.
- Requires ongoing management of hybrid environments.
Choosing the right strategy depends on business goals, application complexity, and regulatory requirements.
The cloud migration process: checklist
A successful cloud migration project typically involves the following phases:
Assessment and planning
- Conduct a comprehensive inventory of all IT assets, applications, and data.
- Map dependencies and identify critical workloads and potential risks.
- Build a business case, define clear objectives, and secure stakeholder buy-in.
- Review compliance obligations and industry regulations relevant to your data and workloads.
Selecting the right cloud provider(s)
- Evaluate cloud vendors based on security, compliance, performance, and support.
- Review service level agreements (SLAs), data residency options, and integration with existing systems.
- Consider multi-cloud or hybrid approaches for flexibility and risk mitigation.
- Factor in long-term costs, including data egress, storage, and ongoing management.
Designing the migration
- Prioritise workloads for migration based on complexity, business value, and risk.
- Define migration waves or phases, starting with non-critical or easily portable applications.
- Choose the most suitable migration approach (from the 6 Rs) for each workload.
- Develop detailed migration runbooks and rollback plans.
Migration execution
- Use migration tools to automate data and application transfer where possible.
- Encrypt data during transit and verify integrity post-migration.
- Refactor or replatform applications as required, ensuring compatibility with the target environment.
- Conduct comprehensive testing, including performance, security, and user acceptance.
Cutover and go-live
- Plan for minimal disruption by scheduling cutovers during low-usage periods.
- Perform final data synchronisation and validation.
- Switch production workloads to the cloud and monitor closely for issues.
- Communicate changes to users and provide support during the transition.
Post-migration optimisation
- Continuously monitor resource usage, application performance, and costs.
- Right-size cloud resources to avoid over-provisioning.
- Implement automated scaling and cost management tools.
- Review and update security and compliance controls as needed.
Cloud to cloud migration: unique challenges and best practices
Cloud-to-cloud migration is becoming increasingly common as organisations seek to avoid vendor lock-in or capitalise on better features and pricing elsewhere. Key challenges include:
Data transfer complexity
- Large volumes of data may require special transfer mechanisms or dedicated network links.
- Ensuring data consistency and integrity during migration is critical.
- Managing encryption keys and access controls across providers.
Application compatibility
- Mapping services, APIs, and configurations between different cloud platforms.
- Addressing differences in service offerings, such as database engines or storage types.
- Refactoring applications to use provider-specific features or to remain portable.
Downtime and disruption
- Minimising service interruptions for users by leveraging blue-green or canary deployment strategies.
- Running parallel environments and gradually switching traffic to the new cloud.
- Communicating planned outages and progress to stakeholders.
Cost management
- Monitoring for overlapping costs during the transition period.
- Reviewing licensing implications and potential cost savings post-migration.
- Using cost calculators and monitoring tools to track expenses in real time.
Best practices for cloud-to-cloud migration include:
- Mapping all dependencies and data flows to avoid missed connections or service gaps.
- Using automated migration tools and scripts to reduce manual errors and speed up the process.
- Running parallel environments for testing and validation before final cutover.
- Establishing robust backup, rollback, and disaster recovery plans in case of migration issues.
Security, compliance and governance
Security and compliance must be at the forefront of any cloud migration. IT leaders should:
Work closely with legal and compliance teams
Identify all relevant regulations (GDPR, HIPAA, PCI DSS, etc.) and ensure cloud providers meet these standards.
Document data flows and storage locations for audit purposes.
Implement robust identity and access management
Enforce least privilege and role-based access controls (RBAC).
Enable multi-factor authentication (MFA) for all users accessing cloud resources.
Encrypt data in transit and at rest
Use strong encryption protocols and manage keys securely.
Regularly review and update encryption policies as threats evolve.
Monitor for threats and maintain an incident response plan
Employ cloud-native security tools for threat detection and response.
Define clear escalation paths and responsibilities in case of security incidents.
Cloud-to-cloud migration adds further complexity, as data may traverse different jurisdictions and compliance regimes.
Common challenges and how to overcome them
Skills gaps
- Invest in training for internal teams on cloud technologies and migration best practices.
- Partner with experienced consultants or managed service providers for complex migrations.
- Foster a culture of continuous learning and knowledge sharing.
Legacy applications
- Assess cloud readiness of legacy systems and plan for refactoring or replacement where needed.
- Use virtualisation or containerisation to lift and shift workloads that cannot be easily modernised.
- Retire obsolete applications to reduce technical debt.
Change management
- Engage stakeholders from across the business early in the process.
- Communicate the benefits, risks, and timelines of migration projects.
- Provide training and support to users as they adapt to new cloud-based systems.
Cost overruns
- Set clear budgets and monitor cloud spend using dashboards and alerts.
- Regularly review resource utilisation and eliminate waste.
- Negotiate with cloud providers for volume discounts or reserved instances where appropriate.
Conclusion
Cloud migration, including cloud-to-cloud migration, is a strategic imperative for organisations seeking agility, innovation and resilience. By understanding the different migration types, planning carefully, and following best practices, IT leaders can steer their organisations towards a more flexible and future-ready technology landscape. The journey may be complex, but with the right approach and mindset, the rewards are considerable.
