How to Migrate Your On-Premise App to Azure: A Step-by-Step Guide

Quick Summary

Introduction

For teams that are used to working with on-premise systems, migrating their legacy application to the cloud may seem like a big move. However, with the growing demand for scalability, reliability, and faster delivery, many organizations are now exploring Microsoft Azure for their cloud requirements. In fact, according to Microsoft, over 95% of Fortune 500 companies already use Azure as part of their cloud strategy.

Azure stands out because it easily integrates with existing Microsoft environments, supports several programming languages and frameworks, and offers strong tools for security, automation, and cost management. Whether you want to migrate a legacy application or completely modernize your on-premise infrastructure, Azure makes it easy to achieve at your own pace with minimal disruption.

But how do you migrate on-premise app to Azure? Let’s understand this step by step.

Top 6 Steps to Migrate On-Premise App to Azure

Here is a detailed breakdown of the six key steps you need to follow to migrate an on-premise application to Azure:

Step 1: Assess the Application

Start by understanding the current state of your application. Not every workload needs to suit the cloud, as some may require adjustments. Begin with a full assessment of the following:

• Architecture: Identify whether the application uses a monolithic or modular structure. Modular applications(applications that use services or containers) can scale and adapt more easily in the cloud.
• Dependencies: List all the systems connected with your on-premises application. These might include on-premise databases, external APIs, file shares, authentication services, or third-party libraries.
• Performance requirements: Record CPU usage, memory demand, storage footprint, and response times during normal and peak operations.
• Compliance and security needs: Check if your application manages sensitive data that must comply with standards like HIPAA, GDPR, or industry-specific controls.

Use Azure Migrate to help with discovery and dependency mapping. This tool also provides cost estimates and compatibility checks, which allow you to prepare a realistic migration plan.

Step 2: Choose the Right Migration Approach

Once you understand your application requirements, choose a migration method that balances effort, cost, and business value. The most common migration approaches include:

• Rehost (Lift and Shift): This method moves the application to Azure Virtual Machines with minimal to no changes. It works well for stable, legacy systems that do not require immediate modernization.
• Refactor: In this method, you have to modify the parts of the application so it can use Azure-native services such as App Service or Azure SQL Database. This improves scalability and reduces operational overhead without major code changes.
• Rearchitect: Here, you have to redesign the application to take full advantage of Azure capabilities like Kubernetes, Event Grid, or Service Bus. This is a great option if you want your application to be more flexible, quickly adapt to changes, and grow smoothly without running into problems.
• Rebuild: Rebuilding involves redeveloping the application from scratch using cloud-native technologies such as Azure Functions or serverless architectures. Choose this method only when the existing app cannot meet future demands or is too expensive to maintain.

For many businesses, the right approach may involve a mix of these strategies.

Step 3: Set Up the Azure Environment

Before moving any workloads, establish a solid foundation in Azure. Create the right structure to support the application now and in the future.

• Create a subscription aligned with your organization’s billing, access, and compliance policies.
• Build a resource group structure based on business units or application tiers. This will make it easier to manage, control, and track usage.
• Design the network by setting up Virtual Networks, Subnets, Network Security Groups, and firewall rules. Include private endpoints if your application requires secure connections.
• Define access controls using Azure Active Directory and role-based access policies. Limit permissions based on job function.
• Provision for the required services, which can include compute (VMs or App Services), data storage (Blob Storage, SQL, or Cosmos DB), and backup or disaster recovery options.

A well-organized environment makes application management easy, helps keep things secure, and reduces future configuration errors.

Step 4: Transfer the Data

After you have set up your Azure environment for the migration, the next step is transferring your on-premises data from your on premise system to Azure. This step is critical and should be done carefully to prevent any issues, particularly for live or production systems.

• Select the right migration tools, like Azure Database Migration Service for structured data, AzCopy for file storage, or Azure Data Factory for pipelines. These tools can help you move large datasets easily and securely.
• Create a non-production environment that mimics your production setup. Use this to test the migration process and identify any gaps.
• Copy the data during off-peak hours or in phases to reduce disruption. If your data needs to remain available, consider continuous replication before switching over.
• Validate everything after the transfer. Confirm that data is intact, permissions are accurate, and applications can access what they need.

Avoid manual interventions during data migration unless absolutely necessary. Use automation tools to streamline the process and cut down on human errors.

Step 5: Deploy the Application in Azure

After preparing the environment and moving the data, deploy the application code in Azure.

• To automate the deployment process, use DevOps tools like Azure DevOps, GitHub Actions, or Jenkins. These tools support repeatable processes and rollback in case of failure.
• Configure runtime settings, which include connection strings, environment variables, and integration points.
• Use monitoring tools such as Azure Monitor, Application Insights, and Log Analytics. These tools can help you with real-time visibility into performance, reliability, and user behavior.
• Test the application under normal usage and simulate high-traffic conditions to check performance deviations and stability.
• Review the cost by analyzing usage reports in Azure Cost Management. Adjust the size of your services and resources if possible, to avoid cloud waste.

Always include a fallback plan. If deployment introduces errors, the team should know how to restore the prior state.

Step 6: Finalize the Migration

Once the application runs successfully in Azure and meets your performance and security standards, it is time to complete the migration.

• Decommission the on-premise servers to reduce confusion and eliminate extra infrastructure costs.
• Update your existing documentation to mention the new cloud architecture, service endpoints, and access policies.
• Train your team on how to manage Azure services. Focus on monitoring, security, and optimization practices.
• Establish governance policies to define backup routines, patching schedules, cost alerts, and access reviews.

This final step ensures that the migration is not just a one-time effort but a permanent shift toward better operations.

Conclusion