In a recent project, we delivered over 60 Microservices deployed on multiple Tomcat servers each in Production.
Below are some notes on real-life learnings.
Designing the Microservices:
Benefits:
Constraints:
Below are some notes on real-life learnings.
Designing the Microservices:
•Business
focus
•Small services with CRUD operations on single business function or domain
•Small services with CRUD operations on single business function or domain
•Design
•Use Lightweight REST based communication (client-to-service and service-to-service)
•Keep Loosely Coupled
•Ensure Services are Stateless
•Appropriate design patterns such as Aggregator, Proxy & Branch Patterns are commonly used
•In unavoidable cases - there will be Distributed Transactions and need to design for them
•Use Lightweight REST based communication (client-to-service and service-to-service)
•Keep Loosely Coupled
•Ensure Services are Stateless
•Appropriate design patterns such as Aggregator, Proxy & Branch Patterns are commonly used
•In unavoidable cases - there will be Distributed Transactions and need to design for them
•Resilience
•Must design for Failure – e.g. Delays, Errors or Unavailability of another service or 3rd party system.
•Provide default functionality in case of failures from a service
•Rely on Input Validation - (client-to-service and service-to-service)
•Must design for Failure – e.g. Delays, Errors or Unavailability of another service or 3rd party system.
•Provide default functionality in case of failures from a service
•Rely on Input Validation - (client-to-service and service-to-service)
•Observability
•Centralized Logging and Monitoring is a must across distributed microservices
•Centralized Logging and Monitoring is a must across distributed microservices
•Log
events for timeouts and shut downs
•Logging
to include the level, hostname (instance name), message
•Log
events can be used for capacity planning and scaling e.g. which services need
higher instances
•Business
data related metrics such as no. of Bookings, Time taken to fill out the form
•Log
events which can be used for capacity planning and scaling
•Automation
•Use Testing tools for integration of services
•Quick feedback on check-ins and failures in the CI/CD pipeline
•Use Testing tools for integration of services
•Quick feedback on check-ins and failures in the CI/CD pipeline
§Independent
Development teams
•Business
domain-driven design
•Responsive
to business changes
§Independent
Deployments
•Minimal
impact and regression testing for small fixes
•Able
to quickly take down and redeploy one service without impact to the overall
system or other functional services.
§Independent
Scalability
•Slots
well into on-demand hosting and cloud services for scalability
§Reusability
for other Enterprise projects
§Higher
Complexity for developers initially
§Deal
with error handling, timeouts, retry mechanisms
§Service
versioning can get confusing and needs to be managed.
§Managing
Distributed Transactions requires Design rework.
§Requires
increased number of VMs to support environments adding to infrastructure costs
§Need clear deployment strategy at the start to identify which services will be deployed on which VMs
§Need clear deployment strategy at the start to identify which services will be deployed on which VMs
§Increased
overhead for Configuration management and Rundeck/UDeploy deployments during project life cycle
and in production as a result of 60+ separate code builds and deployments
§Across
environments, there are 240+ Tomcat Servers in Production and 480+ Servers in lower environments
