Step-by-Step Azure Cloud Migration Process

1. Plan the Migration

Assessment: Analyze the current environment (servers, databases, dependencies, and configurations).

Inventory: List all application components, their dependencies, and resource usage.

Sizing: Map current resource usage to Azure services (VM sizes, Azure SQL, etc.).

Network Design: Plan Azure Virtual Network (VNet), subnets, Network Security Groups (NSGs), and connectivity.

Backup Plan: Define rollback and fallback strategies for potential migration issues.

2. Prepare the Azure Environment

VNet Configuration: Create a VNet with subnets spanning multiple regions or availability zones.

Security: Configure NSGs, Azure RBAC policies, and Azure Active Directory roles.

Database Setup: Set up Azure SQL Database, Azure Managed Instance, or Azure VM for custom database deployment.

AD Server: Use Azure Active Directory Domain Services (AADDS) or deploy a custom AD on Azure VMs.

Application Server: Set up Azure VMs or leverage Azure App Service for hosting.

3. Migrate Database

Backup: Take a full backup of the on-prem database.

Export/Import: Use Azure Database Migration Service (DMS) or native tools to migrate data.

Replication: Configure real-time replication for the database during migration.

Validation: Verify database consistency and integrity after the migration.

4. Migrate Application Server

Packaging: Package the application (e.g., containers, VHDs, or binaries).

Deployment: Deploy the application on Azure VMs, Azure App Service, or Azure Kubernetes Service (AKS).

DNS Configuration: Update DNS records to point to the Azure-hosted application.

5. Migrate Active Directory (AD)

Replication: Set up Azure AD Connect to synchronize your on-prem AD with Azure AD.

Azure ADDS: Deploy Azure AD Domain Services if using a managed AD service.

DNS Sync: Sync DNS records to maintain proper domain resolution.

Validation: Ensure authentication, Group Policies, and access permissions work as expected.

6. Test and Validate

End-to-End Testing: Validate application functionality, database connections, and AD integration.

Performance Checks: Use Azure Monitor and Application Insights to identify bottlenecks.

Failover Testing: Simulate failure scenarios and validate disaster recovery plans.

7. Cutover and Go Live

Schedule Downtime: Coordinate a maintenance window with stakeholders to minimize impact.

Final Sync: Perform a last sync of database and application changes.

Traffic Switch: Update DNS to route traffic to Azure resources.

Monitoring: Use Azure Monitor and Log Analytics for real-time insights into resource performance.

8. Post-Migration Optimization

Scaling: Configure auto-scaling and load balancing for application servers.

Security: Regularly update NSGs, RBAC roles, and review security best practices.

Cost Management: Use Azure Cost Management to analyze and optimize expenditures.

Downtime Considerations

Database Migration: Schedule a downtime window of 2–4 hours for the final sync and cutover.

DNS Propagation: Depending on TTL settings, DNS changes may take 15 minutes to 24 hours. Configure shorter TTLs during the migration phase.

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