Azure migration: how to prepare systems and applications for the transition to the cloud?

Azure migration is much more than moving IT infrastructure to a new environment. It is a project that affects system architecture, data security, application integrations, maintenance costs, and the future development of the organization. Therefore, a successful migration to Azure cloud services requires proper preparation of systems, applications, and business processes above all.

IT migration does not have to mean a revolution. More and more companies implement it in stages, starting with areas that will benefit most quickly from Azure’s flexibility and scalability. It is also an opportunity to organize architecture, reduce technical debt, and prepare the environment for AI and further digital transformation.

A common mistake is starting the project from the technological side without first defining the expected business outcome.

For one organization, company migration to the cloud means lower infrastructure maintenance costs and greater service availability. For another, it is the foundation for application modernization, the development of AI-based solutions, or faster deployment of new products.

The objective should determine the choice of architecture and migration strategy. Without it, it is easy to build an environment that works correctly from a technical perspective but does not support business goals.

Every Azure migration should begin with an assessment of the current environment. The assessment includes:

• business applications and systems,
• servers and infrastructure,
• databases,
• integrations,
• resource utilization,
• licenses,
• security requirements,
• availability and business continuity.

Not every application is ready for a simple move to the cloud. Before starting migration, it is worth verifying:

• the technologies and frameworks used,
• library versions,
• the way data and files are stored,
• environment configuration,
• relationships with other systems,
• performance requirements,
• the application deployment model.

Special attention should be given to legacy systems that have evolved over many years without complete modernization. Their architecture is often not suited to cloud environments.

In such cases, a more important question than “migrate or not?” is determining which components should be moved unchanged, which should be optimized, and which should be rebuilt.

Cloud data migration is one of the most sensitive elements of the project. Errors can affect reporting, financial settlements, operational processes, and customer service.

Therefore, before starting data migration to Microsoft Azure, it is necessary to analyze:

• data quality,
• relationships between datasets,
• duplicates,
• permission assignment methods,
• retention policies,
• archiving,
• compliance with legal requirements.

A good practice is to prepare a plan that includes data mapping, environment cleanup, test migrations, validation, backup, and a rollback scenario. The larger and more complex the organization, the more important the quality of this preparation becomes.

Even a correctly migrated application can cause problems if the organization does not take dependencies between systems into account, especially integrations with ERP, CRM, financial systems, data warehouses, e-commerce platforms, and third-party partner solutions.

Before migration, it is worth creating a data flow map and determining which integrations will remain unchanged, which require redesign, and which can be replaced with Azure services. This reduces the risk of downtime and facilitates phased migration.

Secure cloud migration should be considered already at the architecture design stage. The migration plan should include:

• identity and access management,
• roles and permissions,
• data encryption,
• backup and recovery,
• monitoring,
• network segmentation,
• event logging,
• compliance requirements.

In Microsoft Azure, these areas are supported by, among others, Microsoft Entra ID, Azure Backup, and Azure Monitor, making it easier to control access, monitor the environment, and reduce the risk of incidents.

The cost of migration to Microsoft Azure depends on the environment architecture, services used, data transfer, licensing, and availability requirements. To avoid uncontrolled cost increases, it is worth preparing a cost model and implementing FinOps principles already at the planning stage.

Not every application requires the same approach. In practice, companies most often use the 6R model, which helps align the scope of changes with business value and the technical condition of the system.

• Rehost – moving a system to Azure without major changes.
• Replatform – making minor adjustments to an application for cloud services.
• Refactor – modernizing selected code and architecture components.
• Rearchitect – redesigning the solution for cloud architecture.
• Rebuild – building the application from scratch using modern Azure services.
• Replace – replacing the existing solution with a SaaS service.

Within a single organization, different systems may require different strategies. Factors such as application criticality, technical debt, costs, security, and development plans determine the choice.

A phased or hybrid approach is usually the most effective, where part of the environment remains on-premises while selected systems are moved to Azure. Many companies begin by preparing an Azure Landing Zone, the target environment that includes resource structure, networking, security policies, and governance principles.

The migration plan should define the order of system transfers, responsibilities, schedule, testing approach, and contingency scenarios.

It most often includes:

• environment assessment,
• target architecture design,
• Azure environment preparation,
• pilot deployment,
• production migration,
• validation,
• stabilization and post-implementation support.

A good practice is to start with less critical systems and only then migrate key business processes.

Azure migration affects data, applications, and business processes, which is why it requires a solid testing plan.

Before launching the production environment, verify:

• application functionality,
• performance,
• data integrity,
• user processes,
• integrations,
• logging,
• permissions,
• reporting.

Backup, a rollback plan, and a precise definition of the conditions for considering the migration successful are equally important.

Launching the production environment does not mark the end of the project. The first weeks are usually a hypercare phase involving intensive monitoring and rapid response to issues.

During this time, organizations focus on:

• monitoring,
• cost optimization,
• performance improvement,
• integration stabilization,
• documentation updates,
• user support.

Only after stabilization can organizations fully leverage Azure capabilities and plan further environment modernization.