Per User Rate Limiting

Security

If your site is attacked by a malicious user are you prepared?

If you notice users who are abusing their limitless permissions and overwhelming the httpbin endpoint, you can ensure fairness and protect your site from vulnerabilities by enabling rate limiting based off the incoming client IP address. We do this with the remote_address field that Envoy configures on each request.

  1. Install Ambassador Pro

    Ambassador Pro is a commercial version of Ambassador that includes integrated Single Sign-On, powerful rate limiting, custom filters, and more. Ambassador Pro also uses a certified version of Ambassador OSS that undergoes additional testing and validation.

    1. Clone the Ambassador Pro configuration repository

      Ambassador Pro consists of a series of modules that communicate with Ambassador. The core Pro module is typically deployed as a sidecar to Ambassador. This means it is an additional process that runs on the same pod as Ambassador. Ambassador communicates with the Pro sidecar locally. Pro thus scales in parallel with Ambassador. Ambassador Pro also relies on a Redis instance for its rate limit service and several Custom Resource Definitions (CRDs) for configuration.

      For this installation, we'll start with a standard set of Ambassador Pro configuration files.

      git clone https://github.com/datawire/pro-ref-arch
    2. License Key

      Copy env.sh.example to env.sh, and add your specific license key to the env.sh file. If you don’t have a license key, you can request a free 14-day trial key now.

      Note: Ambassador Pro will not start without a valid license key.

    3. Deploy Ambassador Pro

      If you're on GKE, first, create the following ClusterRoleBinding:

      kubectl create clusterrolebinding my-cluster-admin-binding \
      --clusterrole=cluster-admin \
      --user=$(gcloud info --format="value(config.account)")
      

      Then, deploy Ambassador Pro:

      make apply-ambassador

      This make command will use kubectl to deploy Ambassador Pro and a basic test configuration to the cluster.

      Verify that Ambassador Pro is running:

      kubectl get pods | grep ambassador
      ambassador-79494c799f-vj2dv            2/2       Running            0         1h
      ambassador-pro-redis-dff565f78-88bl2   1/1       Running            0         1h
      

      Note: If you are not deploying in a cloud environment that supports the LoadBalancertype, you will need to change the ambassador/ambassador-service.yaml to a different service type (e.g., NodePort).

      By default, Ambassador Pro uses ports 8081 and 8082 for rate-limiting and filtering, respectively. If for whatever reason those assignments are problematic (perhaps you set service_port to one of those), you can set adjust these by setting environment variables:

      • GRPC_PORT: Which port to serve the RateLimitService on; 8081 by default.
      • APRO_AUTH_PORT: Which port to serve the filtering AuthService on; 8082 by default.

      If you have deployed Ambassador with AMBASSADOR_NAMESPACE, AMBASSADOR_SINGLE_NAMESPACE, or AMBASSADOR_ID set, you will also need to set them in the Pro container.

  2. Configure the label in the Mapping

    In the pro-ref-arch, observe the Mapping in ambassador/04-httpbin.yaml we deployed earlier. You will see a label applied that labels requests to /httpbin/ with the requests remote_address. Ambassador Pro's rate limiting service will use this label to identify the client IP of the request.

         ---
         apiVersion: ambassador/v1
         kind:  Mapping
         name:  httpbin_mapping
         prefix: /httpbin/
         service: httpbin.org:80
         host_rewrite: httpbin.org
         labels:
           ambassador:
             - request_label_group:
               - remote_address
  3. Configure the RateLimit

    kubectl apply -f ratelimit/rl-per-user.yaml

    This will tell Ambassador Pro's rate limiting service to limit the number of requests from each user to 20 requests per minute. This will stop our greedy users from issuing too many requests while not impacting the performance of our more considerate users.

  4. Test The rate limit

    We provide a simple way to test that this rate limit is working. By running the ratelimit-test.sh script in "local-user" mode you will see that your local machine is issuing a lot of request to the system and Ambassador is responding with a 429 after 20 requests.

    ratelimit/ratelimit-test.sh local-user

    Now, from another terminal, run the ratelimit-test.sh script in "remote-user" mode to verify that only your local machine is being rate limited. This will issue a kubectl exec command to issue curl requests from Ambassador running inside your cluster. You will see these requests are allowed through even though your local machine is locked out.

    ratelimit/ratelimit-test.sh remote-user

Summary

Protect your site from malicious users. To enable per user rate limiting quickly and easily, get started with a free 14-day trial of Ambassador Pro, or contact sales today.