A critical enterprise system, developed two decades ago, operates stably but cannot quickly respond to new business requirements such as integration with mobile applications or external APIs. A complete rewrite of such a system involves millions in costs, months of development, and high risks. Meanwhile, ignoring new opportunities leads to a loss of competitiveness. This is a typical scenario for many Ukrainian enterprises where legacy systems form the backbone of the business, but their architecture hinders innovation.
Why integrating legacy and microservices in a hybrid cloud is challenging
Integrating outdated monolithic systems with modern microservices is a complex task due to fundamental differences in architecture, technologies, and development principles. Legacy systems are often based on outdated technologies, have a rigid structure, a monolithic codebase, and limited scalability. They may use proprietary protocols or have complex dependencies that complicate their integration with external services.
Microservices, conversely, are independent, easily scalable components that interact via APIs. They are developed using modern programming languages, frameworks, and cloud technologies. Key challenges include:
- Technological gap: Differences in technology stacks, programming languages, and databases.
- Architectural differences: Monolith versus distributed systems.
- Data management: Synchronizing data across different storage systems and formats.
- Security: Ensuring a unified security and access policy in a hybrid environment.
- Monitoring and management: Complexity of monitoring and managing distributed systems.
Integration strategies: from wrapping to modernization
There are several approaches to integrating legacy systems with microservices, each with its own advantages and disadvantages:
1. Wrapping
This approach involves creating an API layer around the legacy system, allowing microservices to interact with it without delving into its internal logic. This minimizes the risks of modifying the old system and enables rapid integration of new functionalities.
- Advantages: Quick implementation, minimal risk to the legacy system.
- Disadvantages: Does not address the scalability and performance issues of the legacy system, can introduce additional latency.
2. Strangler Fig Pattern
This strategy involves gradually extracting functionality from the monolith into separate microservices. New functionality is developed as microservices, and old functionality is gradually replaced or rewritten. This process can take years but allows for minimized risks and maintained business continuity.
- Advantages: Gradual migration, low risk, ability to modernize individual components.
- Disadvantages: Long-term process, requires careful planning and management.
3. Adapters and message brokers
Using adapters (Enterprise Application Integration, EAI) or message brokers (e.g., Apache Kafka, RabbitMQ) enables asynchronous interaction between legacy systems and microservices. This helps decouple systems and increase their fault tolerance.
| Strategy | Description | Advantages | Disadvantages |
|---|---|---|---|
| API Wrapping | Creating an API layer around the legacy system. | Fast integration, low risk. | Does not solve legacy architectural problems. |
| Strangler Fig Pattern | Gradual extraction of functionality into microservices. | Controlled modernization, risk reduction. | Long-term process, management complexity. |
| Message Brokers | Asynchronous interaction via message queues. | System decoupling, fault tolerance. | Additional infrastructure complexity. |
Benefits of a hybrid cloud for integration
A hybrid cloud plays a key role in this integration, providing a flexible environment for hosting both legacy systems (typically in a private cloud or on-premise) and new microservices (in a public cloud). This allows companies to:
- Optimize costs: Utilize the public cloud for scalable microservices and keep critical data on-premise.
- Increase flexibility: Rapidly deploy new services and adapt to changing market demands.
- Ensure security: Store sensitive data and applications in a controlled private environment, using the public cloud for less sensitive workloads.
- Reduce risks: Gradually migrate functionality without interrupting the operation of core systems.
How Softline solves this
The Softline team has extensive experience in system integration and modernization of enterprise systems, enabling them to successfully address the challenge of integrating legacy systems with microservices in a hybrid cloud.
- Custom development on the UnityBase platform: Softline utilizes its proprietary Low-Code platform, UnityBase, for rapid development of new microservices and API layers. UnityBase allows for the creation of high-performance enterprise systems that easily integrate with existing solutions due to its extensive API capabilities and support for modern protocols. This is ideal for implementing the “wrapping” strategy or gradual functional migration.
- System integration: Softline specialists develop customized solutions for integrating ERP/CRM, HR systems, and other enterprise applications using API interfaces and message brokers. This ensures seamless interaction between legacy components and new microservices.
- Cloud solutions and hybrid infrastructure: Softline provides services for deploying and managing hybrid infrastructure (IaaS/PaaS/SaaS), cloud migration, and cloud resource optimization. This allows companies to host microservices in the public cloud while keeping legacy systems on-premise or in a private cloud, ensuring reliable connectivity and security.
- IT consulting: Softline experts conduct audits of existing architecture, develop modernization and migration strategies, and provide project management support, ensuring compliance with legislation and best practices.
Integrating legacy systems with microservices in a hybrid cloud is not just a technical task but a strategic decision that opens up new business opportunities. Start with a thorough analysis of the existing architecture and identification of critical integration points. A gradual approach using API wrapping and microservices will minimize risks and ensure the continuous evolution of your IT systems.
Successful integration of legacy systems with microservices in a hybrid cloud demands a deep understanding of both architectural patterns and business processes. In practice, it's often more effective to focus on API-fying key functionalities rather than full rewrites, allowing for rapid value realization while minimizing risk.