This document discusses strategies for migrating legacy .NET applications to Azure. It begins by outlining expectations and common scenarios for legacy vs cloud-native applications. It then covers considerations for migrating different application types like thick clients, websites, and services. Key aspects addressed include database options, security, performance, and pricing. The document provides a 3 step approach of assessment, migration, and optimization. It offers numerous Azure-specific resources and tools to assist with migration.

1. Kevin Grossnicklaus
President
kvgros@architectnow.net | @kvgros
architectnow.net | @architectnow
Migrating Legacy .NET Apps to Azure

2. EXPECTATIONS

3. What are we going to
discuss?
How deep are we going?
How can I get help and
advice?
Are you going to focus on
the “why” or the “how”
to move to Azure?

4. COMMON SCENARIOS

5. What do we consider
“Legacy”?
What do we consider “Cloud
Native”?

6. INTERNAL VS.
EXTERNAL APPS
THICK CLIENTS VS
WEBSITES VS
SERVICES
DATABASE OPTIONS SECURITY AND
NETWORK
CONSIDERATIONS
PERFORMANCE AND
AVAILABILITY
MAINTAINABILITY PRICING

8. • I want to deploy code and let
someone else handle the
configuration, maintenance, and
uptime of the infrastructure
Platform as a
Service
(PaaS)
• Give me access low level VM’s and
OS’s and I’ll handle configuring
everything myself
Infrastructure
as a Service
(SaaS)

9. Hybrid Deployments
Migrate some aspects of an application in the cloud and
maintain others internally
Data Center selection is critical
Be Creative and use Common Sense

10. STEP 1: ASSESSMENT

11. DEV OPS

12. Cloud deployments should be
automated
Before a Cloud migration serious
consider transitioning to a cloud-based
dev ops provider
Azure DevOps or GitHub

13. Plan for multiple
environments
Development
Testing
Staging
Production
Document Configuration Changes
Automate via Azure Pipelines

16. THICK APPLICATIONS (WINDOWS)

17. • WinForms or WPF
• Direct to DB or via API’s?
• Need access to local machine (ie. Printing, etc)?
• Basic “Lift and Shift” only
• Ability to use any .NET Framework version and (nearly) any 3rd party
components
Architecture
• Virtual Machines
• Remote Desktop Service (RDS)
• Hybrid Architectures
Hosting Options

18. Considerations
•Keep local but move API or database to
the cloud
•Shared RDS server or other VM
configuration
•Security (can auth against Azure AD or
O365)

19. WEB APPLICATIONS

20. • (Generally) Technology/Language Agnostic
• Support for a vast variety of architectures
• Easier to “Lift and Shift”
Architecture
• Virtual Machines
• App Services
• Docker/Kubernetes
Hosting Options

21. App Services = IIS (or
Apache)
Easier to scale, manage, and
troubleshoot
Access to wide varieties of .NET
framework
App Service Migration
Tool
https://appmigration.microsoft.com
Considerations
Reading/Writing files
Session state (shouldn’t be using)

22. SERVICES

23. • Long running or scheduled services
• Typically a “Windows Service”
• Easier to “Lift and Shift”
Architecture
• Virtual Machines
• App Services
• Docker/Kubernetes
• Azure Functions (Scheduled)
• Data Factory
• Microsoft Flow
Hosting Options

24. Considerations
• Communication with UI
• Data center selection
• Queuing Infrastructure
• Reading/Writing Files (consider move to
Blob storage)
• Monitoring or logging (Azure Monitor)

25. DATABASES

26. Database Options
• Any (if using VM)
• SQL Azure
• Cosmos DB
• MySQL
• PostgreSQL
• Many others
supported by 3rd
parties (i.e. MongoDB
Atlas)
Hosting Options
• Virtual Machines
• Native Offerings

27. • Data center selection
• Redundancy (possible Geolocated)
• Backups
• Security
• Multiple Environments
• Managing Schema Changes
Considerations
• https://docs.microsoft.com/en-us/sql/dma/dma-
overview?view=sql-server-2017
Data Migration
Assistant

30. FILE STORAGE

31. • Dynamic storage of files
Architecture
• Blob Storage
• Mapped Drives
Hosting Options

32. Considerations
Abstraction of file access code
Migration of existing files
Data Box https://azure.microsoft.com/en-
us/services/databox/

33. SECURITY

34. • Very flexible infrastructure to design full network topology
• Can likely design an equivalent (or better) environment than
utilized currently
Architecture
• Azure AD
• VNETS
• Firewalls
• Load Balancer
• ExpressRoute
• https://azure.microsoft.com/en-us/services/expressroute/
Hosting Options

37. PRICING

38. Sketch out proposed Azure architecture
Evaluate this against current infrastructure
• Gauge usage, storage requirements, etc
Review and get advice early on
Azure Price Calculator
• https://azure.microsoft.com/en-us/pricing/calculator/

39. Considerations
• Plan on multiple environments
• Use actuals when estimating (if possible)
• Plan on scalability and availability
• Organize assets via Azure tenants, subscriptions, and
resource groups
• Keep and eye on consumption/spend after launch
• Identify opportunities to use less and “scale up” as needed
(no overkill)
• Monitor usage and invoices
• Can be watched daily
• Work with an Azure CSP

40. Azure SQL Pricing
• DTUs
• vCore
DTU Pricing Calculator
• http://dtucalculator.azurewebsites.net/

42. LICENSING
• IaaS vs PaaS
• 3rd Party Tools

43. Azure Cloud Solution Providers
Managed Services and Support
Pay single bill for
• Office365 or M365
• Development Tools
• Azure Consumption
• Dynamics365

44. STEP 2: MIGRATE

45. .NET Core vs. Full Framework
3rd Party Components
• Commercial or Open Source
Target containerization
Automate build/deployment
Design with monitoring in mind
Consider how to load test and prove scale
Consider modularizing app and deployments
• Website vs API vs Mobile
• Separate versioning

46. Consider Infrastructure as Code
•Terraform - https://www.terraform.io/
•Pulumi - https://www.pulumi.com
•Example

47. STEP 3: OPTIMIZE

48. Refactor and extend code to better leverage the environment
Typically this means we phase in the use of native Azure technologies
Examples
• Docker/Kubernetes
• Azure Functions
• Service Bus
• Data Factories
• Redis Cache
• Azure Search
• Cognitive Services
• Artificial Intelligence
• Machine Learning
• Azure AD
• Azure Frontdoor - https://azure.microsoft.com/en-us/services/frontdoor/
• API Management Services - https://azure.microsoft.com/en-us/services/api-management/
• Traffic Manager

49. Azure SDK’s provided for most
platforms
•.NET = Nuget packages
•JS = NPM

50. Example: Azure Functions
• Serverless code execution
• C# or JavaScript
• Scheduled or triggered

51. RESOURCES

52. Azure
Migrate
https://azure.microsoft.com/en-us/services/azure-
migrate/
Data
Migration
Assistant
https://docs.microsoft.com/en-us/sql/dma/dma-
overview?view=sql-server-2017
App Service
Migration
Assistant
https://appmigration.microsoft.com/
Data Box https://azure.microsoft.com/en-
us/services/databox/
GitFlow https://nvie.com/posts/a-successful-git-branching-
model/

53. Kevin Grossnicklaus
President
kvgros@architectnow.net | @kvgros
architectnow.net | @architectnow