Posts Tagged ‘ReactiveSystems’
[ScalaDaysNewYork2016] Perfect Scalability: Architecting Limitless Systems
Michael Nash, co-author of Applied Akka Patterns, delivered an insightful exploration of scalability at Scala Days New York 2016, distinguishing it from performance and outlining strategies to achieve near-linear scalability using the Lightbend ecosystem. Michael’s presentation delved into architectural principles, real-world patterns, and tools that enable systems to handle increasing loads without failure.
Scalability vs. Performance
Michael Nash clarified that scalability is the ability to handle greater loads without breaking, distinct from performance, which focuses on processing the same load faster. Using a simple graph, Michael illustrated how performance improvements shift response times downward, while scalability extends the system’s capacity to handle more requests. He cautioned that poorly designed systems hit scalability limits, leading to errors or degraded performance, emphasizing the need for architectures that avoid these bottlenecks.
Avoiding Scalability Pitfalls
Michael identified key enemies of scalability, such as shared databases, synchronous communication, and sequential IDs. He advocated for denormalized, isolated data stores per microservice, using event sourcing and CQRS to decouple systems. For instance, an inventory service can update based on events from a customer service without direct database access, enhancing scalability. Michael also warned against overusing Akka cluster sharding, which introduces overhead, recommending it only when consistency is critical.
Leveraging the Lightbend Ecosystem
The Lightbend ecosystem, including Scala, Akka, and Spark, provides robust tools for scalability, Michael explained. Akka’s actor model supports asynchronous messaging, ideal for distributed systems, while Spark handles large-scale data processing. Tools like Docker, Mesos, and Lightbend’s ConductR streamline deployment and orchestration, enabling rolling upgrades without downtime. Michael emphasized integrating these tools with continuous delivery and deep monitoring to maintain system health under high loads.
Real-World Applications and DevOps
Michael shared case studies from IoT wearables to high-finance systems, highlighting common patterns like event-driven architectures and microservices. He stressed the importance of DevOps in scalable systems, advocating for automated deployment pipelines and monitoring to detect issues early. By embracing failure as inevitable and designing for resilience, systems can scale across data centers, as seen in continent-spanning applications. Michael’s practical advice included starting deployment planning early to avoid scalability bottlenecks.
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[ScalaDaysNewYork2016] Lightbend Lagom: Crafting Microservices with Precision
Microservices have become a cornerstone of modern software architecture, yet their complexity often poses challenges. At Scala Days New York 2016, Mirco Dotta, a software engineer at Lightbend, introduced Lagom, an open-source framework designed to simplify the creation of reactive microservices. Mirco showcased how Lagom, meaning “just right” in Swedish, balances developer productivity with adherence to reactive principles, offering a seamless experience from development to production.
The Philosophy of Lagom
Mirco emphasized that Lagom prioritizes appropriately sized services over the “micro” aspect of microservices. By focusing on clear boundaries and isolation, Lagom ensures services are neither too small nor overly complex, aligning with the Swedish concept of sufficiency. Built on Play Framework and Akka, Lagom is inherently asynchronous and non-blocking, promoting scalability and resilience. Mirco highlighted its opinionated approach, which standardizes service structures to enhance consistency across teams, allowing developers to focus on domain logic rather than infrastructure.
Development Environment Efficiency
Lagom’s development environment, inspired by Play Framework, is a standout feature. Mirco demonstrated this with a sample application called Cheerer, a Twitter-like service. Using a single SBT command, runAll, developers can launch all services, including an embedded Cassandra server, service locator, and gateway, within one JVM. The environment supports hot reloading, automatically recompiling and restarting services upon code changes. This streamlined setup, consistent across different machines, frees developers from managing complex scripts, enhancing productivity and collaboration.
Service and Persistence APIs
Lagom’s service API is defined through a descriptor method, specifying endpoints and metadata for inter-service communication. Mirco showcased a “Hello World” service, illustrating how services expose endpoints that other services can call, facilitated by the service locator. For persistence, Lagom defaults to Cassandra, leveraging its scalability and resilience, but allows flexibility for other data stores. Mirco advocated for event sourcing and CQRS (Command Query Responsibility Segregation), noting their suitability for microservices. These patterns enable immutable event logs and optimized read views, simplifying data management and scalability.
Production-Ready Features
Transitioning to production is seamless with Lagom, as Mirco demonstrated through its integration with SBT Native Packager, supporting formats like Docker images and RPMs. Lightbend Conductor, available for free in development, simplifies orchestration, offering features like rolling upgrades and circuit breakers for fault tolerance. Mirco highlighted ongoing work to support other orchestration tools like Kubernetes, encouraging community contributions to expand Lagom’s ecosystem. Circuit breakers and monitoring capabilities further ensure service reliability in production environments.