This cloud migration is the process of moving all data, applications and services from on-premises data centers to a cloud provider’s servers. This process is generally extensive and requires thorough planning and testing to ensure efficient execution.

Hybrid cloud migration involves moving a portion of resources to public cloud while leaving others in on-premises data centers. This hybrid cloud scenario allows organizations to take advantage of current investments in on-premises infrastructure while also using the flexibility, efficiency, strategic value and other benefits of public cloud.

Enterprises also use hybrid cloud migration for data backup. In this case, a company backs up its private cloud resources on a public cloud as a mitigation technique when an attack or disaster renders an on-premises data center inoperable.

Organizations might move their resources from one public cloud to another for many reasons. These reasons include taking advantage of specific pricing models, security features or products (such as new AI or machine learning tools) or because of changes to company structure or service level agreements.  

Another option is to migrate specific workloads to the cloud. For example, an organization might choose to migrate certain databases or mainframes to the cloud as a way to capitalize on lower costs, or for more reliable performance, better security and other factors.

The first step in the workflow is cloud migration planning, which includes clearly articulating the business case for the migration. After the team has established the reasons for the migration, it’s important thoroughly assess existing IT infrastructure, apps and data to identify what’s suitable for migration and to assess dependencies that require attention. In this phase, teams typically:

• List and categorize apps and data
  
• Analyze app dependencies and interdependencies
  
• Evaluate security and compliance requirements
  
• Assess performance and scalability needs
  
• Establish migration goals and priorities
  
• Identify potential migration challenges

When the assessment is complete, it’s time to select the cloud provider that best aligns with business needs. Some factors to consider:

• Provider compatibility with existing apps and data
  
• Service offerings, pricing models and support capabilities
  
• Data sovereignty and compliance considerations
  
• Scalability and availability of required resources
  
• Interoperability with existing systems

This process involves determining how apps, data and infrastructure are organized in the cloud environment. Key considerations include:

• Designing scalable and resilient cloud architectures
  
• Defining networking and security configurations
  
• Identifying appropriate cloud services and features
  
• Optimizing cost-efficiency and performance
  
• Ensuring data backup and disaster recovery mechanisms

In this stage, the team transfers the existing IT infrastructure to the new cloud environment. Depending on the migration strategy (such as lift-and-shift, replatforming or refactoring), the execution process involves:

• Setting up the target cloud environment
• Provisioning virtual machines, storage and network resources
• Replicating or migrating data to the cloud
• Deploying and configuring apps in the new cloud infrastructure

Rigorous testing is vital to ensuring the functionality of newly transferred apps and data. Many teams choose to conduct:

• Functional testing to validate application migration
• Performance and load testing to assess scalability and responsiveness
• Security testing to identify vulnerabilities and ensure compliance
  
• User acceptance testing to validate end-user experience

It’s also important to resolve any issues or bugs identified during the testing and validation process.

At this point, the focus shifts to optimizing the cloud resources and configurations. This step entails:

• Fine-tuning applications
  
• Installing the necessary security measures and access controls
  
• Setting up monitoring and alerting mechanisms
  
• Streamlining resource usage
  
• Establishing governance and management processes

But cloud adoption isn’t a single-step process. Massive infrastructure and data transfers require continuous, real-time performance monitoring to really optimize the features of the new cloud infrastructure and ensure the long-term success of the migration. Organizations should be prepared to update or upgrade software and security protocols, scale up or down based on demand patterns, and monitor cloud costs to optimize cost-effectiveness.

Typically the quickest and least complex migration approach, rehosting (also called lift-and-shift) involves migrating applications and data from onsite infrastructure to a cloud platform without making significant changes to the architecture, likely by using IaaS tools. However, this transfer strategy doesn’t fully take advantage of cloud-native features, so it’s best for applications that aren’t tightly coupled to the underlying infrastructure.

A replatforming (also known as lift-and-reshape) cloud strategy attempts to use some cloud-native features while maintaining compatibility by making specific, but minimal, changes to the existing IT architecture. A few examples of cloud-native features include microservice architecture, Kubernetes containers and machine learning models. 

A refactoring, or rearchitecting, approach requires the organization to redesign and redevelop applications by using a PaaS tool to fully use cloud-native capabilities. Since it often requires significant changes to existing architecture, it tends to make data migration more scalable, resilient and efficient in the cloud environment. Refactoring allows businesses to maximize the business value of cloud systems and use modern architectural patterns and models, such as microservices and serverless computing.

The repurchasing strategy involves retiring an existing application and replacing it with a SaaS alternative. Instead of migrating the application to the cloud, businesses opt for a cloud-based SaaS system that meets their needs. This approach provides instant access to cloud-based applications without the need for significant development efforts. Repurchasing can be useful for transferring non-core applications like email, customer relationship management and human resources management.

Finally, to implement a retiring approach, businesses must decommission outdated and unused applications. As part of the migration process, teams identify extraneous applications or systems and shut them down, reducing maintenance costs, eliminating redundant resources and streamlining the migration process by focusing only on critical applications.