Tools
Microservices Tools
- Registry and Discovery Server (Eureka)
- API Gateway (Zuul is deprecated; Spring Cloud Gateway API is latest)
- Config Server (GitHub)
- Circuit Breaker (Hystrix is deprecated; Resilience4j is latest)
- Distributed Logging & Tracing (Sleuth & Zipkin or ELK Stack)
Reference: https://javatechonline.com/microservices-architecture/#Common_Tools_Frameworks_with_Spring_Cloud
Service Mesh
Manages everything about microservices in a cluster
Takes care of - service registry & discovery, gateway, load balancing, configs, log tracing & metrics, network policies and whitelisting, circuit breaking and retry, etc..
Traffic splitting & canary deployment (aka Rolling upgrades) are easier when we have a service mesh
Motto - separate all the above responsibilities from microservice to service mesh framework; that’s why microservice don’t have hefty code doing all the above (Single Responsibility Principle)
Sidecar proxy
An app is injected and runs alongside our microservice in the same pod, the communication is done between proxy apps. No need for any additional logic in the actual microservice.
Istio
Istio extends Kubernetes to establish a service mesh.
- Istio is configured in k8s YAML files, no need to change microservices code
- We just need to config in the control plane, proxies can even work without talking to the control plane
- Envoy proxies communicate using HTTP/2 and gRPC
Istio Gateway
- Deployed as a service
- Ingress to our cluster from outside - acts as a Load Balancer too
Other popular service mesh implementations are - Hashicorp Consul and linkerd (much faster than Istio).