Egress Passthrough to Unknown Destinations

This guide demonstrates a client within the service mesh accessing destinations external to the mesh using FSM’s Egress capability to passthrough traffic to unknown destinations without an Egress policy.

Prerequisites

• Kubernetes cluster version v1.19.0 or higher.
• Interact with the API server using kubectl.
• FSM CLI installed.
• FSM Ingress Controller installed followed by installation document

HTTP(S) mesh-wide Egress passthrough demo

1. Enable global egress passthrough 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":{"enableEgress":true}}}'  --type=merge
   

2. 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
   

3. Confirm the curl client is able to make successful HTTPS requests to the httpbin.org website on port 443.

   kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I https://httpbin.org:443
   
   HTTP/2 200
   date: Tue, 16 Mar 2021 22:19:00 GMT
   content-type: text/html; charset=utf-8
   content-length: 9593
   server: gunicorn/19.9.0
   access-control-allow-origin: *
   access-control-allow-credentials: true
   

   A 200 OK response indicates the HTTPS request from the curl client to the httpbin.org website was successful.

4. Confirm the HTTPS requests fail when mesh-wide egress is disabled.

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

   Let’s trigger the request again, and you will find it failed this time.

   kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I https://httpbin.org:443
   
   curl: (7) Failed to connect to httpbin.org port 443 after 114 ms: Couldn't connect to server
   

command terminated with exit code 7 ```