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

Prerequisites

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

HTTP(S) mesh-wide Egress passthrough demo

1. Enable global egress passthrough if not enabled:

   export osm_namespace=osm-system # Replace osm-system with the namespace where OSM is installed
   kubectl patch meshconfig osm-mesh-config -n "$osm_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
   osm namespace add curl
   # Deploy curl client in the curl namespace
   kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.0/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 osm-mesh-config -n "$osm_namespace" -p '{"spec":{"traffic":{"enableEgress":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 https://httpbin.org:443
     curl: (7) Failed to connect to httpbin.org port 443 after 3 ms: Connection refused
     command terminated with exit code 7