Microservices Infrastructure on AWS: Patterns for Service Discovery, Communication, and Isolation

Microservices architecture trades monolith complexity for distributed system complexity. The operational requirements change significantly: instead of managing one application, you manage dozens. Instead of one deployment, you manage dozens of independent deployments. The infrastructure layer needs to support this complexity without becoming a bottleneck.

Service Discovery

When Service A needs to call Service B, it needs to know Service B's address. In a microservices system where services scale independently and instances come and go, static configuration doesn't work. You need service discovery.

AWS App Mesh with AWS Cloud Map provides service discovery for ECS and EKS workloads: services register themselves, callers query Cloud Map to find current addresses. QuickInfra's ECS Fargate templates can be configured with App Mesh sidecar proxies for service mesh capabilities.

For simpler cases, an internal Application Load Balancer per service provides a stable DNS name — services discover each other by fixed internal hostnames rather than dynamic IPs.

Service-Level Isolation

Each microservice should have its own:

• Target group / load balancer — isolated ingress
• Security group — explicit allow rules for which services can call it
• IAM task role — least-privilege access to AWS services
• ECR repository — independent container image lifecycle

QuickInfra manages each service as a separate deployment project with its own infrastructure configuration, keeping per-service isolation at the infrastructure level.

API Gateway

For public-facing microservices, AWS API Gateway provides a managed API layer: routing, authentication, rate limiting, request transformation, and API documentation. QuickInfra supports API Gateway provisioning as part of infrastructure projects — the gateway, routes, integrations, stages, and usage plans.

Circuit Breakers

A microservices system where one slow service causes cascading failures throughout the system is a common failure mode. Circuit breakers (implemented in your service code or via a service mesh) stop calls to failing services and return cached responses or errors immediately, preventing the cascade.

At the infrastructure level, ECS Service Connect (AWS's built-in service mesh) provides circuit breaking without requiring a separate sidecar like Envoy.

Data Isolation

Microservices should own their data — each service has its own database, not a shared schema. This is a design principle, not just an infrastructure one, but the infrastructure layer should enforce it: different services should not share database credentials or have direct network access to each other's databases.

QuickInfra's security group templates for database resources default to allowing access only from the specific application security group, making cross-service database access structurally difficult.