Consul Service Splitter Routes All Traffic to One Subset

You encounter a consul configuration issue that prevents your workflow from completing. This guide walks through the fix step by step.

Wrong ❌

apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceSplitter
metadata: { name: my-service }
spec:
  splits:
    - weight: 90, service: my-service-v1
    - weight: 10, service: my-service-v2

Wrong Output

All traffic goes to my-service-v1. No traffic reaches my-service-v2.

Right ✅

apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceResolver
metadata: { name: my-service }
spec:
  defaultSubset: v1
  subsets:
    v1: { filter: "Service.Meta.version == v1" }
    v2: { filter: "Service.Meta.version == v2" }
---
apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceSplitter
metadata: { name: my-service }
spec:
  splits:
    - weight: 90, service: my-service, serviceSubset: v1
    - weight: 10, service: my-service, serviceSubset: v2

Right Output

Traffic split: 90% v1, 10% v2. Canary rollout working as expected.

Prevention

• Create ServiceResolver with subsets before ServiceSplitter.
• Use serviceSubset to reference resolver subsets.
• Start with 90/10 split and gradually shift.
• Verify distribution with Consul sidecar metrics.
• Monitor error rates for each subset.

DodaTech applies similar defensive patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro infrastructure for production reliability.

Common Mistakes with service splitter

1. Forgetting that lazy evaluation defers computation until the value is forced, causing space leaks with unevaluated thunks
2. Using return to exit a function early instead of wrapping a pure value in the monad
3. Mixing let bindings with <- bindings in do notation, producing type errors

These mistakes appear frequently in real-world CONSUL code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

This quick fix is part of the DodaTech infrastructure engineering series. Learn more at DodaTech tutorials.