To enforce external authentication policies, your service mesh environment must have an external auth server. Choose from the following options.

Set up the Gloo Mesh external auth server

To enforce external auth policies across your service mesh environment, each Gloo Mesh Enterprise workspace must have one and only one external auth server. You can configure an ExtAuthServer resource to customize the server behavior, or use the default settings.

  1. Register your workload clusters with the ext-auth-service enabled. Gloo Mesh Enterprise automatically creates a deployment and service of an external auth server. The example steps set up a separate gloo-mesh-addons namespace to run the external auth server. Use this namespace to refer to your server in the ExtAuthServer resource.

  2. Optional: To group the external auth services across clusters, create a virtual destination. This way, you get traffic management benefits like location-aware, priority-based routing.

      kubectl apply --context ${REMOTE_CONTEXT2} -f - <<EOF
    apiVersion: networking.gloo.solo.io/v2
    kind: VirtualDestination
    metadata:
      annotations:
        cluster.solo.io/cluster: ""
      name: ext-auth-service-global
      namespace: gloo-mesh-addons
    spec:
      hosts:
      - ext-auth-service.vd
      ports:
      - number: 8083
        protocol: GRPC
      services:
      - labels:
          app: ext-auth-service
    EOF
      

    Review the following table to understand this configuration. For more information, see the API reference.

    SettingDescription
    --context ${REMOTE_CONTEXT2}The virtual destination is created in cluster2 to demonstrate how virtual destinations group services across clusters.
    app: ext-auth-serviceThe virtual destination elects the default ext-auth-service that you enabled during installation. This default installation meets the requirements to use a virtual destination as the destination server:
    • The service name (ext-auth-service) and namespace (gloo-mesh-addons) match across clusters.
    • The namespace is Istio-injected so that the ext auth service pods have sidecars.
  3. Create an ExtAuthServer resource for your workspace. This resource points to the destination server to use for external auth policies. The destination server can be the default ext-auth-service from your Gloo Mesh Enterprise installation, your own custom server, or the virtual destination that you optionally created in the previous step.

    Review the following table to understand this configuration.
    SettingDescription
    metadataThe name and namespace for this external auth server resource. You can have only one external auth server resource per workspace. This resource does not have to be in the same namespace as the destination server. However, if this resource and the destination server are not in the same workspace, this resource’s workspace must import the destination server’s service.
    destinationServerThe external auth server for Gloo Mesh Enterprise to use to enforce external auth policies. The examples select either a virtual destination or the default Gloo Mesh Enterprise Kubernetes service. If unset, Gloo Mesh Enterprise looks for a service with the name extauth in the same namespace as the Gloo Mesh Enterprise agent on each cluster where the selected workload is deployed. This destination server does not have to be in the same workspace as the external auth server configuration or external auth policies. However, you must export the destination server’s service to those workspaces.
  4. In your external auth policies, refer to the ExtAuthServer to use. In the example, the server configuration is referred to only by name because the policy is created in the same namespace.

Bring your own external auth server

Gloo Mesh Enterprise comes with an external auth server that implements a wide array of authentication and authorization models. However, you can deploy your own external auth server. Then, configure Gloo Mesh Enterprise to use this custom server to secure routes with external auth policies.

For example, you might create a custom external auth server to implement custom logic or to accept requests on certain routes.

The following steps demonstrate how to create a simple HTTP external auth server. Use these steps as a model to deploy your own gRPC server that implements the Envoy spec for an external authorization server.

Before you begin

  1. Complete the multicluster getting started guide to set up the following testing environment.

    • Three clusters along with environment variables for the clusters and their Kubernetes contexts.
    • The Gloo meshctl CLI, along with other CLI tools such as kubectl and istioctl.
    • The Gloo management server in the management cluster, and the Gloo agents in the workload clusters.
    • Istio installed in the workload clusters.
    • A simple Gloo workspace setup.
  2. Install Bookinfo and other sample apps.
  3. Get the external address of your ingress gateway. The steps vary depending on the type of load balancer that backs the ingress gateway.

    • LoadBalancer IP address:
        export INGRESS_GW_IP=$(kubectl get svc -n gloo-mesh-gateways istio-ingressgateway -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
      echo $INGRESS_GW_IP
        
    • LoadBalancer hostname:
        export INGRESS_GW_IP=$(kubectl get svc -n gloo-mesh-gateways istio-ingressgateway -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')
      echo $INGRESS_GW_IP
        

    Note: Depending on your environment, you might see <pending> instead of an external IP address. For example, if you are testing locally in kind or minikube, or if you have insufficent permissions in your cloud platform, you can instead port-forward the service port of the ingress gateway:

      kubectl -n gloo-mesh-gateways port-forward deploy/istio-ingressgateway-1-21 8081
      
  4. Send a request to verify that you can reach the ratings app without authorization. By default, Gloo allows any request on routes that do not specify authentication. Note that you are sending the request along /ratings/2.

    Example output:

      {"id":1,"ratings":{"Reviewer1":5,"Reviewer2":4}}
      

Create a simple HTTP external auth server

When a request matches a route that has an external auth policy applied, Gloo Mesh Enterprise forwards the request to an external auth service.

If that external auth service returns a 200 OK response, Gloo Mesh Enterprise considers the request to be authorized and sends it to its original destination. If not, Gloo Mesh Enterprise denies the request.

You can fine tune settings such as sending headers or forwarding the body by configuring the ExtAuthServer resource as shown in the previous section. Or, you can create your own external auth server to handle requests.

  1. Implement your external auth server. For example, you might use the following Python app for a simple HTTP server. In this example, only requests to /ratings/1 are authorized. All other requests are denied with a 401 response.

      import http.server
    import socketserver
    
    class Server(http.server.SimpleHTTPRequestHandler):
        def do_GET(self):
            path = self.path
            print("path", path)
            if path.startswith("/ratings/1"):
                self.send_response(200, 'OK')
            else:
                self.send_response(401, 'Not authorized')
            self.send_header('x-server', 'pythonauth')
            self.end_headers()
    
    def serve_forever(port):
        socketserver.TCPServer(('', port), Server).serve_forever()
    
    if __name__ == "__main__":
        serve_forever(8000)
      
  2. Verify that the namespace has Istio auto-injection enabled either through the istio-injection=enabled or istio.io/rev=$REVISION label.

      kubectl get ns -L istio-injection,istio.io/rev --context ${REMOTE_CONTEXT1}
      

    If not, enable auto-injection for the namespace in one of the following ways. For more information, see the Istio docs.

    • If you use Istio revisions to manage Istio upgrades, label the namespace with istio.io/rev=$REVISION.
        export REVISION=$(kubectl get pod -L app=istiod -n istio-system --context $REMOTE_CONTEXT1 -o jsonpath='{.items[0].metadata.labels.istio\.io/rev}')
      echo $REVISION
      kubectl label namespace istio.io/rev=$REVISION --overwrite <namespace>
        
    • If you do not use revisions, label the namespace with istio-injection=enabled.
        kubectl label namespace istio-injection=enabled --overwrite <namespace>
        
    • If you do not want to enable auto-injection, manually inject the Istio sidecar after you complete the next step.
  3. Create the a deployment for your HTTP server app. The following example uses the gcr.io/solo-public/docs/sample-auth:latest sample image, which is based on the HTTP server Python code in the previous step. The deployment is created in the bookinfo namespace.

      kubectl apply --context $REMOTE_CONTEXT1 -f - <<EOF
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: sample-auth
      namespace: bookinfo
      labels:
        app: sample-auth
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: sample-auth
      template:
        metadata:
          labels:
            app: sample-auth
        spec:
          containers:
          - name: sample-auth
            image: gcr.io/solo-public/docs/sample-auth:latest
            imagePullPolicy: IfNotPresent
            ports:
            - containerPort: 8000
    EOF
      
  4. Create a service for your external auth server deployment.

      kubectl apply --context $REMOTE_CONTEXT1 -f - <<EOF
    kind: Service
    apiVersion: v1
    metadata:
      name: auth-service
      namespace: bookinfo
      labels:
        app: sample-auth
    spec:
      selector:
        app: sample-auth # Selects the external auth deployment
      ports:
      - protocol: TCP
        port: 80 # For HTTP traffic
        targetPort: 8000 # Matches the container port of the external auth deployment
        name: http # Include this name so that Gloo Mesh Enterprise knows that this is the HTTP port to use
    EOF
      
  5. Verify that the external auth server is running.

      kubectl get all -l app=sample-auth -n bookinfo --context $REMOTE_CONTEXT1 
      
  6. Optional: Depending on your setup, repeat these steps for each workspace where you want to use the external auth server.

Configure Gloo to use your custom external auth server

Now that you have an external auth server running in your cluster, configure Gloo Mesh Enterprise to use the server for authentication requests. You use an ExtAuthServer custom resource.

  1. Create an ExtAuthServer resource to configure the server.

      kubectl apply --context $REMOTE_CONTEXT1 -f - <<EOF
    apiVersion: admin.gloo.solo.io/v2
    kind: ExtAuthServer
    metadata:
      name: custom-server
      namespace: bookinfo
      labels:
         app: sample-auth
    spec:
      destinationServer:
        port:
          number: 8000
        ref:
          cluster: ${CLUSTER_NAME}
          name: auth-service
          namespace: bookinfo
    EOF
      
    Review the following table to understand this configuration.
    SettingDescription
    metadataThe name and namespace for this external auth server resource. You can have only one external auth server resource per workspace. This resource does not have to be in the same namespace as the destination server. However, if this resource and the destination server are not in the same workspace, this resource’s workspace must import the destination server’s service.
    destinationServerThe external auth server for Gloo Mesh Enterprise to use to authentic requests with an external auth policy. If unset, Gloo Mesh Enterprise looks for a service with the name extauth in the same namespace as the Gloo Mesh Enterprise agent on each cluster where the selected workload is deployed. This destination server does not have to be in the same workspace as the external auth server configuration or external auth policies. However, you must export the destination server’s service to those workspaces.
  2. Create an external auth policy that uses your custom auth server.

      kubectl apply --context $REMOTE_CONTEXT1 -f - <<EOF
    apiVersion: security.policy.gloo.solo.io/v2
    kind: ExtAuthPolicy
    metadata:
      name: custom-auth
      namespace: bookinfo
      labels:
         app: sample-auth
    spec:
      applyToRoutes:
      - route:
          labels:
            route: ratings
      config:
        customAuth: {}
        server:
          name: custom-server
    EOF
      

    Review the following table to understand this configuration. For more information, see the API reference.

    SettingDescription
    applyToRoutesUse labels to configure which routes to apply the policy to. This example label matches the app and route from the example route table that you apply separately. If omitted and you do not have another selector such as applyToDestinations, the policy applies to all routes in the workspace.
    customAuthSet this field to use your own custom auth server.
    serverThe external auth server to use for the policy.
  3. Send a request to the ratings app along the /ratings/2 path. Now, your request is denied because the external auth server allows requests only along the /ratings/1 path.

      curl -vik --resolve www.example.com:80:${INGRESS_GW_IP} http://www.example.com:80/ratings/2
      
  4. Repeat the previous request along the /ratings/1 path.

      curl -vik --resolve www.example.com:80:${INGRESS_GW_IP} http://www.example.com:80/ratings/1
      

    The request succeeds:

      {"id":1,"ratings":{"Reviewer1":5,"Reviewer2":4}}
      

Cleanup

You can optionally remove the resources that you set up as part of this guide.
  kubectl delete deploy,svc,extauthserver,extauthpolicy -n bookinfo -l app=sample-auth --context $REMOTE_CONTEXT1