kong – 2 services same route

techhadoop , , , ,

In Kong Gateway, you cannot have two services bound to the exact same route — a route must be unique in terms of its combination of matching rules (such as paths, hosts, methods, etc.).

🚫 Why You Can’t Have Duplicate Routes

Kong uses the route’s matching criteria to determine which service should handle a request. If two routes have the same matching rules, Kong can’t disambiguate, which leads to a conflict error when trying to create the second route.

For example:

# Service A
curl -i -X POST http://localhost:8001/services/ --data name=service-a --data url=http://api-a
curl -i -X POST http://localhost:8001/routes --data name=route-a --data service.name=service-a --data paths[]=/api

# Service B
curl -i -X POST http://localhost:8001/services/ --data name=service-b --data url=http://api-b
curl -i -X POST http://localhost:8001/routes --data name=route-b --data service.name=service-b --data paths[]=/api

⛔ The second POST /routes will fail with:

HTTP 409 Conflict – duplicate entry

✅ Workarounds / Alternatives

GoalSolution
Blue/Green or Canary DeploymentsUse Kong Plugins (e.g., traffic-split, canary) or upstreams and targets instead of duplicate routes.
Different consumers/users hitting different backendsUse request transformers, ACLs, or Kong Enterprise Route-by-header/Route-by-consumer plugins.
Same path, different method or hostYou can differentiate routes by methods[], hosts[], or headers.

🧪 Example: Two Routes with Same Path, Different Hosts

# Route 1
curl -i -X POST http://localhost:8001/routes \
  --data name=api-v1 \
  --data paths[]=/api \
  --data hosts[]=v1.example.com \
  --data service.name=service-a

# Route 2
curl -i -X POST http://localhost:8001/routes \
  --data name=api-v2 \
  --data paths[]=/api \
  --data hosts[]=v2.example.com \
  --data service.name=service-b

These can coexist because their hosts[] fields are different.

🧠 Summary

Route Matching RuleMust Be Unique For
paths[]Same host/methods/headers
hosts[]If combined with same path
methods[], headersCan disambiguate routes with same path

If you’re trying to achieve load balancing, blue-green deployment, or AB testing between services at the same route — I can help you set that up using upstreams + targets or the traffic-split plugin.

Would you like an example?

Leave a comment