AZ-305 - Design Migrations
Cloud Adoption Framework
The Microsoft Cloud Adoption Framework (CAF) is a comprehensive guide that helps organizations plan and execute their migration to Azure. It provides proven methodology, documentation, and tools that cloud architects and IT professionals use to build a structured migration strategy.
CAF Phases
Plan Phase
In the Plan phase, organizations define their cloud adoption strategy. This includes rationalizing the digital estate, aligning stakeholders, building a skills readiness plan, and creating a cloud adoption plan. The digital estate assessment catalogs all workloads and classifies them according to the Five Rs of rationalization.
Ready Phase
The Ready phase focuses on preparing the Azure environment through landing zones. A landing zone is a pre-provisioned environment configured with governance, networking, identity, and security baselines. Azure Landing Zone accelerators provide automated deployment of recommended architectures.
Adopt Phase
The Adopt phase covers the actual migration and innovation efforts. Migration involves moving existing workloads to Azure, while innovation focuses on building new cloud-native solutions. Both tracks run in parallel, with each iteration improving processes and tooling.
Manage Phase
The Manage phase establishes operational management baselines for the cloud environment. This includes monitoring, business continuity and disaster recovery (BCDR), and ongoing optimization. Azure Monitor, Azure Advisor, and Azure Cost Management are key tools used in this phase.
Azure Migrate: Discovery and Assessment
Azure Migrate provides a centralized hub for discovering, assessing, and migrating on-premises servers, databases, web apps, and virtual desktops to Azure. It consolidates both Microsoft and third-party tools into a single migration experience.
Discovery Process
The Azure Migrate appliance is a lightweight device deployed on-premises that performs agentless discovery. It collects metadata about servers, installed applications, server dependencies, and performance data. The appliance communicates securely with Azure Migrate over HTTPS on port 443.
Discovery Capabilities
Server discovery: Identifies physical and virtual machines across VMware, Hyper-V, and physical environments.
Application discovery: Catalogs installed software, roles, and features on discovered servers.
Dependency analysis: Maps network connections between servers to identify application groups. Supports both agentless (VMware only) and agent-based analysis.
Assessment Types
| Assessment Type | Purpose | Key Output |
|---|---|---|
| Azure VM Assessment | Evaluate readiness for Azure VMs | Right-sized VM recommendations, cost estimates |
| Azure SQL Assessment | Evaluate readiness for Azure SQL | SQL MI or SQL DB recommendations |
| Azure App Service Assessment | Evaluate readiness for App Service | App Service plan and SKU recommendations |
| Azure VMware Solution (AVS) | Evaluate readiness for AVS | Node sizing and cost estimates |
IaaS Migration Strategies
IaaS migration strategies align with the Five Rs of rationalization from the Cloud Adoption Framework. Choosing the right strategy depends on business goals, timeline, budget, and the complexity of the workload.
Rehost (Lift and Shift)
Rehosting moves workloads to Azure without code changes. This is the fastest migration approach and is ideal for organizations that need to quickly vacate a data center. Azure Migrate Server Migration handles agentless or agent-based replication for VMware, Hyper-V, and physical servers.
Refactor (Lift and Reshape)
Refactoring involves minimal changes to applications so they can leverage PaaS services. For example, migrating a web application from IIS on a VM to Azure App Service, or moving a SQL Server database to Azure SQL Database. This approach reduces operational overhead while requiring limited code changes.
Rearchitect
Rearchitecting involves significant modifications to an application to take advantage of cloud-native features. This might include breaking a monolithic application into microservices, adopting serverless patterns, or using managed services like Azure Kubernetes Service. This approach delivers the greatest long-term cloud benefits but requires the most effort.
Rebuild
Rebuilding means rewriting the application from scratch using cloud-native technologies. This approach is appropriate when an existing application has fundamental limitations that prevent effective migration. It offers the maximum potential for cloud optimization but carries the highest cost and longest timeline.
Database Migration
Database migration is often the most critical and complex component of a cloud migration. Azure provides specialized tools and services to help migrate databases with minimal downtime.
Azure Database Migration Service (DMS)
DMS Overview
Azure Database Migration Service is a fully managed service designed to enable seamless migrations from multiple database sources to Azure data platforms. It supports both offline (one-time) and online (continuous sync) migrations.
Offline migration: The source database remains unavailable during the migration. Suitable for applications that can tolerate downtime.
Online migration: DMS continuously replicates changes from source to target while the source remains operational. Requires a final cutover once replication catches up.
Supported Migration Paths
| Source | Target | Migration Type |
|---|---|---|
| SQL Server (on-premises) | Azure SQL Database | Offline / Online |
| SQL Server (on-premises) | Azure SQL Managed Instance | Offline / Online |
| PostgreSQL | Azure Database for PostgreSQL | Offline / Online |
| MySQL | Azure Database for MySQL | Offline |
| MongoDB | Azure Cosmos DB (MongoDB API) | Offline / Online |
PaaS Migration Approaches
Migrating to PaaS services such as Azure App Service, Azure SQL Database, or Azure Cosmos DB can significantly reduce operational burden. Azure App Service Migration Assistant scans web applications and identifies readiness for App Service migration. For containerized workloads, Azure Container Apps or AKS provide managed orchestration platforms.
Migration Validation
Validation is a critical final step in any migration. It ensures that migrated workloads function correctly and meet performance expectations in the Azure environment.
Validation Checklist
Post-Migration Validation Steps
Functional testing: Verify all application features work correctly in the new environment.
Performance benchmarking: Compare response times and throughput against pre-migration baselines.
Data integrity checks: Confirm all data was migrated completely and accurately using row counts, checksums, or hash comparisons.
Security review: Validate network security groups, access controls, encryption, and compliance requirements.
Monitoring setup: Ensure Azure Monitor, Application Insights, and alerting are configured for the migrated workloads.
Key Terms
| Term | Definition |
|---|---|
| Cloud Adoption Framework (CAF) | A comprehensive methodology from Microsoft that provides guidance, best practices, and tools for cloud adoption and migration. |
| Azure Migrate | A centralized hub for discovering, assessing, and migrating on-premises workloads to Azure. |
| Landing Zone | A pre-provisioned Azure environment that includes governance, security, networking, and identity baselines. |
| Rehost | A migration strategy that moves workloads to Azure without modifying the application code (lift and shift). |
| Azure Database Migration Service | A fully managed service that enables online and offline migration of databases to Azure data platforms. |
| Digital Estate | The complete inventory of IT assets (servers, databases, applications) that make up an organization's technology portfolio. |
| Five Rs of Rationalization | Rehost, Refactor, Rearchitect, Rebuild, and Replace - five strategies for rationalizing a digital estate for cloud adoption. |
Exam Tips
- Know the CAF phases: The exam tests your understanding of Plan, Ready, Adopt, and Manage. Remember that Plan comes before Ready, and Adopt includes both migration and innovation tracks.
- Understand the Five Rs: Be able to match each rationalization strategy (Rehost, Refactor, Rearchitect, Rebuild, Replace) to specific scenarios. Rehost is fastest, Rebuild is most effort.
- Azure Migrate is the central hub: Questions about migration tools typically expect Azure Migrate as the starting point. Remember it supports VMware, Hyper-V, and physical servers.
- DMS online vs. offline: Online migration minimizes downtime by continuously replicating changes. Offline migration requires downtime but is simpler. Know which scenario calls for which approach.
- Landing zones are critical: The exam expects you to understand that a landing zone should be established before migration begins. It provides the governance and security foundation.
- Validation is not optional: Post-migration validation including data integrity, performance, and security should always be part of a migration plan.
Practice Questions
Question 1
Your company is planning to migrate 200 virtual machines from an on-premises VMware environment to Azure. The migration must be completed within 3 months with minimal application changes. Which migration strategy should you recommend?
A. Rebuild all applications as cloud-native microservices
B. Rehost the virtual machines using Azure Migrate Server Migration
C. Rearchitect the applications to use Azure Functions
D. Refactor all applications to use Azure App Service
Answer: B
Explanation: Rehosting (lift and shift) is the fastest migration strategy and requires minimal application changes. Azure Migrate Server Migration supports agentless migration from VMware, making it ideal for migrating a large number of VMs within a tight timeline.
Question 2
You need to migrate an on-premises SQL Server database to Azure SQL Managed Instance with minimal downtime. Which tool and migration type should you use?
A. Azure Database Migration Service with offline migration
B. Azure Database Migration Service with online migration
C. SQL Server backup and restore to Azure Blob Storage
D. Azure Data Factory with copy activity
Answer: B
Explanation: Azure Database Migration Service with online migration continuously replicates changes from the source SQL Server to Azure SQL Managed Instance. This approach minimizes downtime because the source database remains operational during replication, requiring only a brief cutover window.
Question 3
Which phase of the Cloud Adoption Framework is responsible for establishing Azure landing zones?
A. Plan
B. Ready
C. Adopt
D. Manage
Answer: B
Explanation: The Ready phase is responsible for preparing the Azure environment, which includes deploying landing zones. Landing zones provide the governance, networking, identity, and security baselines needed before migration workloads can begin in the Adopt phase.
Question 4
Your organization has a legacy monolithic application that cannot be efficiently migrated as-is. The application needs to be decomposed into microservices to take advantage of container orchestration and auto-scaling. Which migration strategy is most appropriate?
A. Rehost
B. Refactor
C. Rearchitect
D. Replace
Answer: C
Explanation: Rearchitecting involves significant modification to an application to take advantage of cloud-native features like microservices and container orchestration. Breaking a monolith into microservices requires changes to the application architecture, which goes beyond simple refactoring.
Question 5
You are using Azure Migrate to discover and assess on-premises servers. You need to identify which servers communicate with each other to group dependent applications. Which Azure Migrate feature should you use?
A. Azure Migrate Server Assessment with performance-based sizing
B. Azure Migrate dependency analysis
C. Azure Migrate Server Migration with test migration
D. Azure Migrate application discovery
Answer: B
Explanation: Azure Migrate dependency analysis maps network connections between servers to identify groups of interdependent machines. This feature supports both agentless analysis (for VMware) and agent-based analysis, and helps you understand which servers should be migrated together as a group.
AZ-305 Designing Azure Infrastructure Solutions - Table of Contents
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