Basic rate limit policy

Control the rate of requests to destinations within the service mesh. The following example shows you how to create a basic rate limit policy that applies to a destination, based on a generic key.

For more in-depth examples of the Envoy and Set-style rate limiting APIs, see More rate limit policy examples.

Before you begin

This guide assumes that you use the same names for components like clusters, workspaces, and namespaces as in the getting started. If you have different names, make sure to update the sample configuration files in this guide.
  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 Platform CLI, meshctl, 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.

Configure rate limit policies

You can apply a rate limit policy at the destination level. For more information, see Applying policies.

Review the following sample configuration files. Continue to the Verify rate limit policies section for example steps on how to check that rate limiting is working.

apiVersion: trafficcontrol.policy.gloo.solo.io/v2
kind: RateLimitPolicy
metadata:
  name: rl-policy
  namespace: bookinfo
spec:
  applyToDestinations:
  - port:
      number: 9080
    selector:
      labels:
        app: reviews
  config:
    ratelimitClientConfig:
      name: rl-client-config
    ratelimitServerConfig:
      name: rl-server-config
      namespace: gloo-mesh-addons
    serverSettings:
      name: rl-server
Review the following table to understand this configuration.
Setting Description
spec.applyToDestinations Configure which destinations to apply the policy to, by using labels. Destinations can be a Kubernetes service, VirtualDestination, or ExternalService. If you do not specify any destinations or routes, the rate limit policy applies to all destinations in the workspace by default. If you do not specify any destinations but you do specify a route, the rate limit applies to the route but to no destinations. In this example, the rate limit policy applies to all destinations in the workspace with the app: reviews label.
config The ratelimitServerConfig is required. The serverSettings and ratelimitClientConfig are optional, and can be added manually in the policy. In this example, the rate limit policy refers to the client config, server config, and server settings that you downloaded before you began. For more information, see Rate limit server setup.

Verify rate limit policies

  1. Make sure that the rate limit server is installed and running. If not, install the rate limiter.
    kubectl get pods --context ${REMOTE_CONTEXT1} -A -l app=rate-limiter
    
  2. Create the rate limit server resources that are required to use rate limiting policies. For more information these resources, see Rate limit server setup.
    kubectl --context ${REMOTE_CONTEXT1} apply -f - <<EOF
    apiVersion: admin.gloo.solo.io/v2
    kind: RateLimitServerConfig
    metadata:
      name: rl-server-config
      namespace: gloo-mesh-addons
    spec:
      destinationServers:
      - port:
          number: 8083
        ref:
          cluster: cluster-1
          name: rate-limiter
          namespace: gloo-mesh-addons
      raw:
        descriptors:
        - key: generic_key
          rateLimit:
            requestsPerUnit: 1
            unit: DAY
          value: counter
    ---
    apiVersion: admin.gloo.solo.io/v2
    kind: RateLimitServerSettings
    metadata:
      name: rl-server
      namespace: bookinfo
    spec:
      destinationServer:
        port:
          number: 8083
        ref:
          cluster: cluster-1
          name: rate-limiter
          namespace: gloo-mesh-addons
    ---
    apiVersion: trafficcontrol.policy.gloo.solo.io/v2
    kind: RateLimitClientConfig
    metadata:
      name: rl-client-config
      namespace: bookinfo
    spec:
      raw:
        rateLimits:
        - actions:
          - genericKey:
              descriptorValue: counter
    EOF
       
  3. Apply the example rate limit policy in your example setup.
    kubectl --context ${REMOTE_CONTEXT1} apply -f - <<EOF
    apiVersion: trafficcontrol.policy.gloo.solo.io/v2
    kind: RateLimitPolicy
    metadata:
      name: rl-policy
      namespace: bookinfo
    spec:
      applyToDestinations:
      - port:
          number: 9080
        selector:
          labels:
            app: reviews
      config:
        ratelimitClientConfig:
          name: rl-client-config
        ratelimitServerConfig:
          name: rl-server-config
          namespace: gloo-mesh-addons
        serverSettings:
          name: rl-server
    EOF
    
  4. Send a request to the reviews app from within a curl pod to test east-west rate limiting.

    Create a temporary curl pod in the bookinfo namespace, so that you can test the app setup. You can also use this method in Kubernetes 1.23 or later, but an ephemeral container might be simpler, as shown in the other tab.

    1. Create the curl pod.

      kubectl run -it -n bookinfo --context $REMOTE_CONTEXT1 curl \
        --image=curlimages/curl:7.73.0 --rm  -- sh
      
    2. Send a request to the ratings app.

      curl http://reviews:9080/reviews/1 -v
      

      Example output:

      {"id":1,"ratings":{"Reviewer1":5,"Reviewer2":4}}200
      

    Use the kubernetes debug command to create an ephemeral curl container in the deployment. This way, the curl container inherits any permissions from the app that you want to test. If you don't run Kubernetes 1.23 or later, you can deploy a separate curl pod or manually add the curl container as shown in the other tab.

    kubectl --context ${REMOTE_CONTEXT1} -n bookinfo debug -i pods/$(kubectl get pod --context ${REMOTE_CONTEXT1} -l app=reviews -A -o jsonpath='{.items[0].metadata.name}') --image=curlimages/curl -- curl -v http://reviews:9080/reviews/1
    

    If the output has an error about EphemeralContainers, see Ephemeral containers don’t work when testing Bookinfo.

  5. Repeat the request. Because the rate limit policy limits requests to 1 per day, the request results in a 429 - Too Many Requests error.
  6. Exit from the curl pod.
  7. Optional: Clean up the Gloo resources that you created to test this policy.
    kubectl --context $REMOTE_CONTEXT1 -n gloo-mesh-addons delete RateLimitServerConfig rl-server-config
    kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete RateLimitServerSettings rl-server
    kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete RateLimitClientConfig rl-client-config
    kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete RateLimitPolicy rl-policy