Permissive Traffic Policy Mode

This guide demonstrates a client and server application within the service mesh communicating using FSM’s permissive traffic policy mode, which configures application connectivity using service discovery without the need for explicit SMI traffic access policies.

Prerequisites

• Kubernetes cluster running Kubernetes v1.19.0 or greater.
• Have FSM installed.
• Have kubectl available to interact with the API server.
• Have fsm CLI available for managing the service mesh.

Demo

The following demo shows an HTTP curl client making HTTP requests to the httpbin service using permissive traffic policy mode.

1. Enable permissive mode if not enabled.

   export FSM_NAMESPACE=fsm-system # Replace fsm-system with the namespace where FSM is installed
   kubectl patch meshconfig fsm-mesh-config -n "$FSM_NAMESPACE" -p '{"spec":{"traffic":{"enablePermissiveTrafficPolicyMode":true}}}'  --type=merge
   

2. Deploy the httpbin service into the httpbin namespace after enrolling its namespace to the mesh. The httpbin service runs on port 14001.

   # Create the httpbin namespace
   kubectl create namespace httpbin
   
   # Add the namespace to the mesh
   fsm namespace add httpbin
   
   # Deploy httpbin service in the httpbin namespace
   kubectl apply -f https://raw.githubusercontent.com/flomesh-io/fsm-docs/main/manifests/samples/httpbin/httpbin.yaml -n httpbin
   

   Confirm the httpbin service and pods are up and running.

   $ kubectl get svc -n httpbin
   NAME      TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)     AGE
   httpbin   ClusterIP   10.96.198.23   <none>        14001/TCP   20s
   

   $ kubectl get pods -n httpbin
   NAME                     READY   STATUS    RESTARTS   AGE
   httpbin-5b8b94b9-lt2vs   2/2     Running   0          20s
   

3. Deploy the curl client into the curl namespace after enrolling its namespace to the mesh.

   # Create the curl namespace
   kubectl create namespace curl
   
   # Add the namespace to the mesh
   fsm namespace add curl
   
   # Deploy curl client in the curl namespace
   kubectl apply -f https://raw.githubusercontent.com/flomesh-io/fsm-docs/main/manifests/samples/curl/curl.yaml -n curl
   

   Confirm the curl client pod is up and running.

   $ kubectl get pods -n curl
   NAME                    READY   STATUS    RESTARTS   AGE
   curl-54ccc6954c-9rlvp   2/2     Running   0          20s
   

4. Confirm the curl client is able to access the httpbin service on port 14001.

   $ kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I http://httpbin.httpbin:14001
   HTTP/1.1 200 OK
   server: gunicorn/19.9.0
   date: Wed, 29 Jun 2022 08:50:33 GMT
   content-type: text/html; charset=utf-8
   content-length: 9593
   access-control-allow-origin: *
   access-control-allow-credentials: true
   connection: keep-alive
   

   A 200 OK response indicates the HTTP request from the curl client to the httpbin service was successful.

5. Confirm the HTTP requests fail when permissive traffic policy mode is disabled.

   kubectl patch meshconfig fsm-mesh-config -n "$FSM_NAMESPACE" -p '{"spec":{"traffic":{"enablePermissiveTrafficPolicyMode":false}}}'  --type=merge
   

   $ kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I http://httpbin.httpbin:14001
   curl: (52) Empty reply from server
   command terminated with exit code 52