Cloud Service Mesh by example: Authorization

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In this tutorial, you will learn what authorization is, and how to enable it with Cloud Service Mesh on a sample application to learn how to enable authorization policies to your microservices. You will create an AuthorizationPolicy to DENY access to a microservice, then create anAuthorizationPolicy to ALLOW specific access to a microservice.

What is authorization?

Authentication verifies an identity -- is this service who they say they are? Authorization verifies the permission - is this service allowed to do that? Identity is fundamental to this idea. With Cloud Service Mesh, AuthorizationPolicies allow for workload-to-workload communication in your mesh to be controlled for improved security and access.

In a microservice architecture, where calls are made across network boundaries, traditional IP-based firewall rules are often not adequate to secure access between workloads. With Cloud Service Mesh, you can set authorization rules to:

• Control access to workloads within your mesh, either workload-to-workload or end-user-to-workload
• Broadly or granularly define policies depending on your needs. To see an in-depth explanation on configuring policies and best practices, see Authorization with Cloud Service Mesh.

Costs

This tutorial uses the following billable components of Google Cloud:

• GKE
• Cloud Service Mesh

When you finish this tutorial, you can avoid ongoing costs by deleting the resources you created. For more information, see Clean up.

Before you begin

• Ensure billing is enabled for your project.

• Provision managed Cloud Service Mesh on a GKE cluster. There are various supported setup methods:

  • Fleet API

  • Google Cloud console UI

Note: Please ensure you have the appropriate cluster requirements for Cloud Service Mesh.

• Clone the repo:

  git clone https://github.com/GoogleCloudPlatform/anthos-service-mesh-samples
  cd anthos-service-mesh-samples
  

Deploy an ingress gateway

1. Set the current context for kubectl to the cluster:

   Note: Use --region instead of --zone, if the cluster is a regional cluster.

   gcloud container clusters get-credentials CLUSTER_NAME  \
   --project=PROJECT_ID \
   --zone=CLUSTER_LOCATION 
   

2. Create a namespace for your ingress gateway:

   kubectl create namespace asm-ingress
   

3. Enable the namespace for injection. The steps depend on your Cloud Service Mesh type (either managed or in-cluster):

   Managed

   Apply the asm-managed revision label to the namespace:

   kubectl label namespace asm-ingress \
     istio-injection- istio.io/rev=asm-managed --overwrite
   

   This label corresponds to the current managed Cloud Service Mesh release channel for the Cloud Service Mesh version.

   In-cluster

   1. Use the following command to locate the revision label on istiod:

      kubectl get deploy -n istio-system -l app=istiod -o \
        jsonpath={.items[*].metadata.labels.'istio\.io\/rev'}'{"\n"}'
      

   2. Apply the revision label to the namespace. In the following command, REVISION is the value of the istiod revision label that you noted in the previous step.

      kubectl label namespace asm-ingress \
        istio-injection- istio.io/rev=REVISION --overwrite
      

4. Deploy the example gateway in the anthos-service-mesh-samples repo:

   kubectl apply -n asm-ingress \
   -f docs/shared/asm-ingress-gateway
   

   Expected output:

   serviceaccount/asm-ingressgateway configured
   service/asm-ingressgateway configured
   deployment.apps/asm-ingressgateway configured
   gateway.networking.istio.io/asm-ingressgateway configured
   

Deploy the Online Boutique sample application

1. If you haven't, set the current context for kubectl to the cluster:

   gcloud container clusters get-credentials CLUSTER_NAME  \
   --project=PROJECT_ID \
   --zone=CLUSTER_LOCATION 
   

2. Create the namespace for the sample application:

   kubectl create namespace onlineboutique
   

3. Label the onlineboutique namespace to automatically inject Envoy proxies. Follow the steps to enable automatic sidecar injection.

4. Deploy the sample app, the VirtualService for the frontend, and service accounts for the workloads. For this tutorial, you will deploy Online Boutique, a microservice demo app.

   kubectl apply \
   -n onlineboutique \
   -f docs/shared/online-boutique/virtual-service.yaml
   kubectl apply \
   -n onlineboutique \
   -f docs/shared/online-boutique/service-accounts
   

View your services

1. View the pods in the onlineboutique namespace:

   kubectl get pods -n onlineboutique
   

   Expected output:

   NAME                                     READY   STATUS    RESTARTS   AGE
   adservice-85598d856b-m84m6               2/2     Running   0          2m7s
   cartservice-c77f6b866-m67vd              2/2     Running   0          2m8s
   checkoutservice-654c47f4b6-hqtqr         2/2     Running   0          2m10s
   currencyservice-59bc889674-jhk8z         2/2     Running   0          2m8s
   emailservice-5b9fff7cb8-8nqwz            2/2     Running   0          2m10s
   frontend-77b88cc7cb-mr4rp                2/2     Running   0          2m9s
   loadgenerator-6958f5bc8b-55q7w           2/2     Running   0          2m8s
   paymentservice-68dd9755bb-2jmb7          2/2     Running   0          2m9s
   productcatalogservice-84f95c95ff-c5kl6   2/2     Running   0          114s
   recommendationservice-64dc9dfbc8-xfs2t   2/2     Running   0          2m9s
   redis-cart-5b569cd47-cc2qd               2/2     Running   0          2m7s
   shippingservice-5488d5b6cb-lfhtt         2/2     Running   0          2m7s
   

   All of the pods for your application should be up and running, with a 2/2 in the READY column. This indicates that the pods have an Envoy sidecar proxy injected successfully. If it does not show 2/2 after a couple of minutes, visit the Troubleshooting guide.

2. Get the external IP, and set it to a variable:

   kubectl get services -n asm-ingress
   export FRONTEND_IP=$(kubectl --namespace asm-ingress \
   get service --output jsonpath='{.items[0].status.loadBalancer.ingress[0].ip}' \
   )
   

   You see output similar to the following:

   NAME                   TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)                                      AGE
   asm-ingressgateway   LoadBalancer   10.19.247.233   35.239.7.64   80:31380/TCP,443:31390/TCP,31400:31400/TCP   27m
   
   

3. Visit the EXTERNAL-IP address in your web browser. You should expect to see the Online Boutique shop in your browser.

   

DenyAll Authorization for a workload

This section adds an AuthorizationPolicy to deny all incoming traffic to the currency service. AuthorizationPolicies work by transforming AuthorizationPolicies into Envoy-readable configs, and applying the configs to your sidecar proxies. This enables the Envoy proxy to authorize or deny incoming requests to a service.

1. Apply an AuthorizationPolicy to the currencyservice. Notice the match on the label currencyservice in the YAML file.

   kubectl apply -f docs/authorization/currency-deny-all.yaml -n onlineboutique
   

   apiVersion: security.istio.io/v1beta1
   kind: AuthorizationPolicy
   metadata:
     name: currency-policy
   spec:
     selector:
       matchLabels:
         app: currencyservice

2. Try accessing your gateway's EXTERNAL-IP to view Online Boutique in the web browser. You should see an authorization error (500 Internal Service Error) from currency service.

   

Observe your sidecar proxy logs

To see what is occurring in the sidecar proxy, you can review the logs in the pod.

1. Get the name of your currencyservice pod:

   CURRENCY_POD=$(kubectl get pod -n onlineboutique |grep currency|awk '{print $1}')
   

2. Set the Envoy proxy to allow for trace level logs. By default, blocked authorization calls are not logged:

   kubectl exec -it $CURRENCY_POD -n onlineboutique -c istio-proxy -- curl -X POST "http://localhost:15000/logging?level=trace"
   

   Expected output: active loggers: admin: trace alternate_protocols_cache: trace ... tracing: trace upstream: trace udp: trace wasm: trace

3. Use curl to send traffic to your EXTERNAL_IP to generate logs:

   for i in {0..10}; do
   curl -s -I $FRONTEND_IP ; done
   

4. View the role-based access control (RBAC) related logs in your istio-proxy:

   kubectl logs -n onlineboutique $CURRENCY_POD -c istio-proxy | grep -m5 rbac
   

   Expected output:

   2022-07-08T14:19:20.442920Z     debug   envoy rbac      checking request: requestedServerName: outbound_.7000_._.currencyservice.onlineboutique.svc.cluster.local, sourceIP: 10.8.8.5:34080, directRemoteIP: 10.8.8.5:34080, remoteIP: 10.8.8.5:34080,localAddress: 10.8.0.6:7000, ssl: uriSanPeerCertificate: spiffe://christineskim-tf-asm.svc.id.goog/ns/onlineboutique/sa/default, dnsSanPeerCertificate: , subjectPeerCertificate: OU=istio_v1_cloud_workload,O=Google LLC,L=Mountain View,ST=California,C=US, headers: ':method', 'POST'
   2022-07-08T14:19:20.442944Z     debug   envoy rbac      enforced denied, matched policy none
   2022-07-08T14:19:20.442965Z     debug   envoy http      [C73987][S13078781800499437460] Sending local reply with details rbac_access_denied_matched_policy[none]
     ```
   

You should see an enforced denied message in the logs, showing that currencyservice is set to block inbound requests.

Allow Restricted Access

Instead of a DENYALL policy, you can set access to be allowed for certain workloads. This will be relevant in a microservice architecture where you want to ensure that only authorized services can communicate with each other.

In this section, you will enable the frontend and checkout service the ability to communicate with the currency service.

1. In the below file, see that a specific source.principal(client) is allowlisted to access currencyservice:

apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: currency-policy
spec:
  selector:
    matchLabels:
      app: currencyservice
  rules:
  - from:
    - source:
        principals: ["cluster.local/ns/onlineboutique/sa/frontend"]
  - from:
    - source:
        principals: ["cluster.local/ns/onlineboutique/sa/checkoutservice"]

Apply the policy:

kubectl apply -f docs/authorization/currency-allow-frontend-checkout.yaml -n onlineboutique

1. Visit the EXTERNAL-IP in your web browser, you should now be able to access Online Boutique.

Clean up

To avoid incurring charges to your Google Cloud account for the resources used in this tutorial, either delete the project that contains the resources, or keep the project and delete the individual resources.

To avoid incurring continuing charges to your Google Cloud account for the resources used in this tutorial, you can either delete the project or delete the individual resources.

Delete the project

Caution: Deleting a project has the following effects:

• Everything in the project is deleted. If you used an existing project for this tutorial, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

In Cloud Shell, delete the project:

gcloud projects delete PROJECT_ID

Delete the resources

• If you want to keep your cluster and remove the Online Boutique sample:

  1. Delete the application namespaces:

     kubectl delete namespace onlineboutique
     

     Expected output:

     namespace "onlineboutique" deleted
     

  2. Delete the Ingress Gateway namespace:

     kubectl delete namespace asm-ingress
     

     Expected output:

     amespace "asm-ingress" deleted
     

• If you want to prevent additional charges, delete the cluster:

  gcloud container clusters delete  CLUSTER_NAME  \
  --project=PROJECT_ID \
  --zone=CLUSTER_LOCATION 
  

What's next

• For a general guide on configuring PeerAuthentication policies, see Configuring transport security.
• Improve your cluster and application's security posture with this tutorial on how to Strengthen your app's security with Cloud Service Mesh, Config Sync, and Policy Controller.
• Explore your mesh's security dashboard with Monitor mesh security.
• Deep dive with authorization policies with Configure authorization policy advanced features.
• Familiarize yourself with Cloud Service Mesh security best practices.