OSM provides the option to use Contour ingress controller and Envoy based edge proxy to route external traffic to service mesh backends. This guide will demonstrate how to configure HTTP and HTTPS ingress to a service part of an OSM managed service mesh.

Prerequisites

  • Kubernetes cluster running Kubernetes v1.19.0 or greater.
  • Have kubectl available to interact with the API server.
  • No existing installation of OSM. Any existing installation must first be uinstalled prior to proceeding with this demo.
  • Have osm or Helm 3 CLI available for installing OSM and Contour.
  • OSM version >= v0.10.0.

Demo

First, we will install OSM and Contour as in the osm-system namespace and name the mesh name as osm.

export osm_namespace=osm-system
export osm_mesh_name=osm

If using osm CLI:

osm install --set contour.enabled=true \
    --set contour.configInline.tls.envoy-client-certificate.name=osm-contour-envoy-client-cert \
    --set contour.configInline.tls.envoy-client-certificate.namespace="$osm_namespace"

If using Helm:

helm install "$osm_mesh_name" osm --repo https://openservicemesh.github.io/osm

To restrict ingress traffic on backends to authorized clients, we will set up the IngressBackend configuration such that only ingress traffic from the endpoints of the osm-contour-envoy service can route traffic to the service backend. To be able to discover the endpoints of osm-contour-envoy service, we need OSM controller to monitor the corresponding namespace.

kubectl label ns "$osm_namespace" openservicemesh.io/monitored-by="$osm_mesh_name"

Save the ingress gateway’s external IP address and port which we will later use to test access to the backend application:

export ingress_host="$(kubectl -n "$osm_namespace" get service osm-contour-envoy -o jsonpath='{.status.loadBalancer.ingress[0].ip}')"
export ingress_port="$(kubectl -n "$osm_namespace" get service osm-contour-envoy -o jsonpath='{.spec.ports[?(@.name=="http")].port}')"

Next, we will deploy the sample httpbin service.

# Create a namespace
kubectl create ns httpbin

# Add the namespace to the mesh
osm namespace add httpbin

# Deploy the application
kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm/main/docs/example/manifests/samples/httpbin/httpbin.yaml -n httpbin

Confirm the httpbin service and pod is up and running:

$ kubectl get pods -n httpbin
NAME                       READY   STATUS    RESTARTS   AGE
httpbin-74677b7df7-zzlm2   2/2     Running   0          11h

$ kubectl get svc -n httpbin
NAME      TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)     AGE
httpbin   ClusterIP   10.0.22.196   <none>        14001/TCP   11h

HTTP Ingress

Next, we will create the HTTPProxy and IngressBackend configurations necessary to allow external clients to access the httpbin service on port 14001 in the httpbin namespace. The connection from the Contour’s ingress gateway to the httpbin backend pod will be unencrypted since we aren’t using TLS.

kubectl apply -f - <<EOF
apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: httpbin
  namespace: httpbin
spec:
  virtualhost:
    fqdn: httpbin.org
  routes:
  - services:
    - name: httpbin
      port: 14001
---
kind: IngressBackend
apiVersion: policy.openservicemesh.io/v1alpha1
metadata:
  name: httpbin
  namespace: httpbin
spec:
  backends:
  - name: httpbin
    port:
      number: 14001
      protocol: http
  sources:
  - kind: Service
    namespace: "$osm_namespace"
    name: osm-contour-envoy
EOF

Now, we expect external clients to be able to access the httpbin service for HTTP requests for the Host: header httpbin.org:

$ curl -sI http://"$ingress_host":"$ingress_port"/get -H "Host: httpbin.org"
HTTP/1.1 200 OK
server: envoy
date: Fri, 06 Aug 2021 17:39:43 GMT
content-type: application/json
content-length: 314
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 3
vary: Accept-Encoding

HTTPS Ingress (mTLS and TLS)

To proxy connections to TLS backends using HTTPS, the backend service must be annotated with the port as follows:

kubectl annotate service httpbin -n httpbin projectcontour.io/upstream-protocol.tls='14001' --overwrite

Next, we need to create an HTTPProxy configuration to use TLS proxying to the backend service, and providing a CA certificate to validate the server certificate presented by the backend service. For this to work, we need to first delegate to Contour the permission to read OSM’s CA certificate secret from the OSM’s namespace when referenced in the HTTPProxy configuration in the httpbin namespace. Refer to the Upstream TLS section to learn more about upstream certificate validation and when certificate delegation is necessary. In addition, we must create an IngressBackend resource that specifies HTTPS ingress traffic directed to the httpbin service must only accept traffic from a trusted client, osm-contour-envoy in the ingress edge proxy we deployed. OSM automatically provisioned a client certificate for the osm-contour-envoy ingress gateway with the Subject ALternative Name (SAN) osm-contour-envoy.osm-system.cluster.local during install, so the IngressBackend configuration needs to reference the same SAN for mTLS authentication between the osm-contour-envoy edge and the httpbin backend.

Apply the configurations:

kubectl apply -f - <<EOF
apiVersion: projectcontour.io/v1
kind: TLSCertificateDelegation
metadata:
  name: ca-secret
  namespace: "$osm_namespace"
spec:
  delegations:
    - secretName: osm-ca-bundle
      targetNamespaces:
      - httpbin
---
apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: httpbin
  namespace: httpbin
spec:
  virtualhost:
    fqdn: httpbin.org
  routes:
  - services:
    - name: httpbin
      port: 14001
      validation:
        caSecret: "$osm_namespace/osm-ca-bundle"
        subjectName: httpbin.httpbin.cluster.local
---
kind: IngressBackend
apiVersion: policy.openservicemesh.io/v1alpha1
metadata:
  name: httpbin
  namespace: httpbin
spec:
  backends:
  - name: httpbin
    port:
      number: 14001
      protocol: https
    tls:
      skipClientCertValidation: false # mTLS (defaults to false)
  sources:
  - kind: Service
    namespace: "$osm_namespace"
    name: osm-contour-envoy
  - kind: AuthenticatedPrincipal
    name: "osm-contour-envoy.$osm_namespace.cluster.local"
EOF

Now, we expect external clients to be able to access the httpbin service for HTTP requests for the Host: header httpbin.org with HTTPS proxying over mTLS between the ingress gateway and service backend:

$ curl -sI http://"$ingress_host":"$ingress_port"/get -H "Host: httpbin.org"
HTTP/1.1 200 OK
server: envoy
date: Fri, 06 Aug 2021 17:39:43 GMT
content-type: application/json
content-length: 314
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 3
vary: Accept-Encoding

To verify that unauthorized clients are not allowed to access the backend, we can update the sources specified in the IngressBackend configuration. Let’s update the principal to something other than the SAN encoded in the ingress gateway’s certificate.

kubectl apply -f - <<EOF
kind: IngressBackend
apiVersion: policy.openservicemesh.io/v1alpha1
metadata:
  name: httpbin
  namespace: httpbin
spec:
  backends:
  - name: httpbin
    port:
      number: 14001
      protocol: https
    tls:
      skipClientCertValidation: false # mTLS (defaults to false)
  sources:
  - kind: Service
    namespace: "$osm_namespace"
    name: osm-contour-envoy
  - kind: AuthenticatedPrincipal
    name: "untrusted-client.cluster.local"
EOF

Confirm the requests are rejected with an HTTP 403 Forbidden response:

$ curl -sI http://"$ingress_host":"$ingress_port"/get -H "Host: httpbin.org"
HTTP/1.1 403 Forbidden
content-length: 19
content-type: text/plain
date: Fri, 06 Aug 2021 18:40:45 GMT
server: envoy
x-envoy-upstream-service-time: 8

Next, we demonstrate support for disabling client certificate validation on the service backend if necessary, by updating our IngressBackend configuration to set skipClientCertValidation: true, while still using an untrusted client:

kubectl apply -f - <<EOF
kind: IngressBackend
apiVersion: policy.openservicemesh.io/v1alpha1
metadata:
  name: httpbin
  namespace: httpbin
spec:
  backends:
  - name: httpbin
    port:
      number: 14001
      protocol: https
    tls:
      skipClientCertValidation: true
  sources:
  - kind: Service
    namespace: "$osm_namespace"
    name: osm-contour-envoy
  - kind: AuthenticatedPrincipal
    name: "untrusted-client.cluster.local"
EOF

Confirm the requests succeed again since untrusted authenticated principals are allowed to connect to the backend:

$ curl -sI http://"$ingress_host":"$ingress_port"/get -H "Host: httpbin.org"
HTTP/1.1 200 OK
server: envoy
date: Fri, 06 Aug 2021 18:51:47 GMT
content-type: application/json
content-length: 314
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 4
vary: Accept-Encoding