How to intercept requests to a service in Kubernetes?

Question

Let's say I define a Service named my-backend in Kubernetes. I would like to intercept every request sent to this service, what is the proper way to do it? For example, another container under the same namespace sends a request through http://my-backend.

I tried to use Admission Controller with a validation Webhook. However, it can intercept the CRUD operations on service resources, but it fails to intercept any connection to a specific service.

Answer 1

There is no direct way to intercept the requests to a service in Kubernetes.

For workaround this is what you can do-

1. Create a sidecar container just to log the each incoming request. logging

2. Run tcpdump -i eth0 -n in your containers and filter out requests

3. Use Zipkin

4. Creating service on cloud providers, will have their own logging mechanism. for ex - load balancer service on aws will have its logs generated on S3. aws elb logs

Answer 2

You can use a service mesh such as istio. An istio service mesh deploys a envoy proxy sidecar along with every pod. Envoy intercepts all the incoming requests to the pod and can provide you metrics such as number of requests etc. A service mesh brings in more features such as distributed tracing, rate limiting etc.