A modernization initiative moves existing applications toward current cloud platforms and operating practices without requiring an immediate rewrite. For organizations with large VM-based estates, rewriting every application can be too slow and expensive. Containerizing existing workloads can improve portability and resource use while providing a path to faster delivery. Modernization need not be all or nothing: an application can gain some cloud-native benefits before it becomes a set of microservices. section 15.0
Start by choosing the application or component to modernize. Assess whether it can move to a container, whether it needs manual conversion, or whether it should remain on a VM. The decision must account for application complexity, interactions with other systems, regulatory requirements, performance, and existing hardware investments. Components of one application may take different paths. section 16.2.1
A staged plan can combine these paths:
- Use Migrate for Anthos to extract a suitable VM workload into a container with its runtime, tools, libraries, code, configuration, and settings. Manually containerize applications that are too complex for that route. section 15.0 section 16.2.1
- Update or create a CI/CD pipeline to build, test, and deploy the containerized application to Anthos. Operate it there with configuration, security, and connectivity to legacy applications under management. section 16.2.1
- Refactor applications toward microservices when appropriate. Move legacy applications not yet suited to containers to Compute Engine for later refactoring; leave applications outside the initiative in their existing environment and secure connections to them with Anthos Service Mesh. section 16.2.1
A mixed application estate
A three-tier Java application is a candidate for component-by-component assessment rather than an automatic full rewrite. One suitable component might be containerized with Migrate for Anthos, while a more complex component needs manual containerization. A connected legacy system can remain in place, with its connection secured through Anthos Service Mesh. The containerized components then enter a CI/CD pipeline before any later microservices refactoring. section 16.2.1 section 15.0
