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

Use the Gloo external auth server

To enforce external auth policies across your service mesh environment, each Gloo Mesh Gateway 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 setting. Gloo Mesh Gateway automatically creates a deployment and service of an external auth server.

    • The example steps deploy the external auth server to the default gloo-mesh namespace. 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
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) 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 Gateway installation, your own custom server, or the virtual destination that you optionally created in the previous step.

      kubectl apply --context ${REMOTE_CONTEXT1} -f - <<EOF
apiVersion: admin.gloo.solo.io/v2
kind: ExtAuthServer
metadata:
  annotations:
    cluster.solo.io/cluster: ""
  name: default-server
  namespace: bookinfo
spec:
  destinationServer:
    kind: VIRTUAL_DESTINATION
    ref:
      cluster: cluster-2
      name: ext-auth-service-global
      namespace: gloo-mesh
EOF
  
      kubectl apply --context ${REMOTE_CONTEXT1} -f - <<EOF
apiVersion: admin.gloo.solo.io/v2
kind: ExtAuthServer
metadata:
  annotations:
    cluster.solo.io/cluster: ""
  name: default-server
  namespace: bookinfo
spec:
  destinationServer:
    port:
      number: 8083
    ref:
      cluster: cluster-1
      name: ext-auth-service
      namespace: gloo-mesh
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 Gateway to use to enforce external auth policies. The examples select either a virtual destination or the default Gloo Mesh Gateway Kubernetes service. If unset, Gloo Mesh Gateway looks for a service with the name extauth in the same namespace as the Gloo Mesh Gateway 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.

      kubectl apply --context ${REMOTE_CONTEXT1} -f - <<EOF
apiVersion: security.policy.gloo.solo.io/v2
kind: ExtAuthPolicy
metadata:
  annotations:
    cluster.solo.io/cluster: ""
  name: basic-auth
  namespace: bookinfo
spec:
  applyToDestinations:
  - port:
      number: 9080
    selector:
      labels:
        app: ratings
  config:
    glooAuth:
      configs:
      - basicAuth:
          apr:
            users:
              user:
                hashedPassword: 8BvzLUO9IfGPGGsPnAgSu1
                salt: TYiryv0/
    server:
      name: default-server
EOF
  
      kubectl apply --context ${REMOTE_CONTEXT1} -f - <<EOF
apiVersion: security.policy.gloo.solo.io/v2
kind: ExtAuthPolicy
metadata:
  annotations:
    cluster.solo.io/cluster: ""
  name: basic-auth
  namespace: bookinfo
spec:
  applyToRoutes:
  - {}
  - route:
      labels:
        route: ratings
  config:
    glooAuth:
      configs:
      - basicAuth:
          apr:
            users:
              user:
                hashedPassword: 8BvzLUO9IfGPGGsPnAgSu1
                salt: TYiryv0/
    server:
      name: default-server
EOF

Bring your own external auth server

Gloo Mesh Gateway 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 Gateway 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. Set up Gloo Mesh Gateway in a single cluster.
  2. Install Bookinfo and other sample apps.

  3. Configure an HTTP listener on your gateway and set up basic routing for the sample apps.

  4. Get the external address of your ingress gateway. The steps vary depending on the type of load balancer that backs the ingress gateway.

     ```shell
 export INGRESS_GW_ADDRESS=$(kubectl get svc -n gloo-mesh-gateways istio-ingressgateway -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
 echo $INGRESS_GW_ADDRESS
 ```

    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 insufficient 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-1-18 8081

  5. 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.

      curl -vik --resolve www.example.com:80:${INGRESS_GW_IP} http://www.example.com:80/ratings/2
  
      curl -vik --resolve www.example.com:443:${INGRESS_GW_IP} https://www.example.com:443/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 Gateway forwards the request to an external auth service.

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

  3. Create a service for your external auth server deployment.

      kubectl apply -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 Gateway knows that this is the HTTP port to use
EOF

  4. Verify that the external auth server is running.

      kubectl get all -l app=sample-auth -n bookinfo

  5. 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 Gateway to use the server for authentication requests. You use an ExtAuthServer custom resource.

  1. Create an ExtAuthServer resource to configure the server.

      kubectl apply -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 Gateway to use to authentic requests with an external auth policy. If unset, Gloo Mesh Gateway looks for a service with the name extauth in the same namespace as the Gloo Mesh Gateway 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 -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