It is an overwhelmingly recognized fact that businesses across the globe can easily attain the elusive goal of reliability by putting highly reliable IT systems in place, as IT is the most direct and greatest business-enabler. However, producing reliable IT systems is beset with a number of challenges and concerns, since IT complexity is consistently on the rise due to the heightened heterogeneity and the growing multiplicity of various information technologies and tools. There have been various approaches, best practices, optimization techniques, patterns, and algorithms recommended by subject matter experts (SMEs) and accomplished architects for consistently moderating IT complexity and for producing reliable IT systems in plenty. Resiliency and elasticity are the top two ingredients for having reliable systems. In other words, business workloads and IT services have to be elegantly resilient and elastic to be reliable in their operations, offerings, and outputs. Microservices architecture (MSA) is being touted as the best way for producing mission-critical, enterprise-grade, production-ready, process-aware, event-driven, service-oriented, and people-centric applications. Furthermore, there are a bevy of innovations and improvements in the MSA space to build and deploy applications that are ingrained with availability, reliability, scalability, performance/throughput, security, simplicity, flexibility, and sustainability capabilities. In this chapter, we will focus on various microservice resiliency patterns that intrinsically and insightfully enable the design, development, debugging, delivery, and deployment of reliable systems. 

In this chapter, we will cover the following topics: 

• The beneficial convergence of microservices and containers
• The IT reliability challenges and solution approaches
• Microservices design, development, deployment, and operations patterns
• Microservice resiliency patterns

• Highly available microservice patterns
• Microservice API Gateway design patterns
• Patterns for application decomposition into microservices