This guide demonstrates how outbound IP address ranges can be excluded from being intercepted by OSM’s proxy sidecar, so as to not subject them to service mesh filtering and routing policies.

Prerequisites

  • Kubernetes cluster running Kubernetes v1.20.0 or greater.
  • Have OSM installed.
  • Have kubectl available to interact with the API server.
  • Have osm CLI available for managing the service mesh.

Demo

The following demo shows an HTTP curl client making HTTP requests to the httpbin.org website directly using its IP address. We will explicitly disable the egress functionality to ensure traffic to a non-mesh destination (httpbin.org in this demo) is not able to egress the pod.

  1. Disable mesh-wide egress passthrough.

    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":false}}}'  --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/main/manifests/samples/curl/curl.yaml -n curl

    Confirm the curl client pod is up and running.

    kubectl get pods -n curl

    The out will be similar to:

    NAME                    READY   STATUS    RESTARTS   AGE
curl-54ccc6954c-9rlvp   2/2     Running   0          20s

  3. Retrieve the public IP address for the httpbin.org website. For the purpose of this demo, we will test with a single IP range to be excluded from traffic interception. In this example, we will use the IP address 54.91.118.50 represented by the IP range 54.91.118.50/32, to make HTTP requests with and without outbound IP range exclusions configured.

    nslookup httpbin.org

    The output will be similar to:

    Server:		172.23.48.1
Address:	172.23.48.1#53

Non-authoritative answer:
Name:	httpbin.org
Address: 54.91.118.50
Name:	httpbin.org
Address: 54.166.163.67
Name:	httpbin.org
Address: 34.231.30.52
Name:	httpbin.org
Address: 34.199.75.4

    Note: Replace 54.91.118.50 with a valid IP address returned by the above command in subsequent steps.

  4. Confirm the curl client is unable to make successful HTTP requests to the httpbin.org website running on http://54.91.118.50:80.

    kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I http://54.91.118.50:80

    The output will be similar to:

    curl: (7) Failed to connect to 54.91.118.50 port 80: Connection refused
command terminated with exit code 7

    The failure above is expected because by default outbound traffic is redirected via the Envoy proxy sidecar running on the curl client’s pod, and the proxy subjects this traffic to service mesh policies which does not allow this traffic.

  5. Program OSM to exclude the IP range 54.91.118.50/32 IP range

    kubectl patch meshconfig osm-mesh-config -n "$osm_namespace" -p '{"spec":{"traffic":{"outboundIPRangeExclusionList":["54.91.118.50/32"]}}}'  --type=merge

  6. Confirm the MeshConfig has been updated as expected

    # 54.91.118.50 is one of the IP addresses of httpbin.org
kubectl get meshconfig osm-mesh-config -n "$osm_namespace" -o jsonpath='{.spec.traffic.outboundIPRangeExclusionList}{"\n"}'
["54.91.118.50/32"]

  7. Restart the curl client pod so the updated outbound IP range exclusions can be configured. It is important to note that existing pods must be restarted to pick up the updated configuration because the traffic interception rules are programmed by the init container only at the time of pod creation.

    kubectl rollout restart deployment curl -n curl

    Wait for the restarted pod to be up and running.

  8. Confirm the curl client is able to make successful HTTP requests to the httpbin.org website running on http://54.91.118.50:80

    # 54.91.118.50 is one of the IP addresses for httpbin.org
kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I http://54.91.118.50:80

    The output will be similar to:

    HTTP/1.1 200 OK
Date: Thu, 18 Mar 2021 23:17:44 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 9593
Connection: keep-alive
Server: gunicorn/19.9.0
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true

  9. Confirm that HTTP requests to other IP addresses of the httpbin.org website that are not excluded fail 34.199.75.4 is one of the IP addresses for httpbin.org

    kubectl exec -n curl -ti "$(kubectl get pod -n curl -l app=curl -o jsonpath='{.items[0].metadata.name}')" -c curl -- curl -I http://34.199.75.4:80

    The output will be similar to:

    curl: (7) Failed to connect to 34.199.75.4 port 80: Connection refused
command terminated with exit code 7