Enabling Rate Limits (Deprecated)

    Consider using Envoy native rate limiting instead of mixer rate limiting. Istio will add support for native rate limiting API through the Istio extensions API.

    This task shows you how to use Istio to dynamically limit the traffic to a service.

    1. Setup Istio in a Kubernetes cluster by following the instructions in the .

      Policy enforcement must be enabled in your cluster for this task. Follow the steps in Enabling Policy Enforcement to ensure that policy enforcement is enabled.

    2. Deploy the sample application.

      The Bookinfo sample deploys 3 versions of the service:

      • Version v1 doesn’t call the ratings service.
      • Version v2 calls the ratings service, and displays each rating as 1 to 5 black stars.
      • Version v3 calls the ratings service, and displays each rating as 1 to 5 red stars.

      You need to set a default route to one of the versions. Otherwise, when you send requests to the reviews service, Istio routes requests to all available versions randomly, and sometimes the output contains star ratings and sometimes it doesn’t.

    3. Set the default version for all services to v1.

      Zip

    Rate limits

    In this task, you configure Istio to rate limit traffic to productpage based on the IP address of the originating client. You will use X-Forwarded-For request header as the client IP address. You will also use a conditional rate limit that exempts logged in users.

    For convenience, you configure the memory quota (memquota) adapter to enable rate limiting. On a production system, however, you need , and you configure the Redis quota (redisquota) adapter. Both the memquota and redisquota adapters support the , so the configuration to enable rate limiting on both adapters is the same.

    1. Rate limit configuration is split into 2 parts.

      • Client Side
        • QuotaSpec defines quota name and amount that the client should request.
        • QuotaSpecBinding conditionally associates QuotaSpec with one or more services.

      Run the following command to enable rate limits using memquota:

      Zip

      1. $ kubectl apply -f @samples/bookinfo/policy/mixer-rule-productpage-ratelimit.yaml@

      If you use Istio 1.1.2 or prior, please use the following configuration instead:

      1. $ kubectl apply -f @samples/bookinfo/policy/mixer-rule-productpage-ratelimit-crd.yaml@

      The memquota handler defines 4 different rate limit schemes. The default, if no overrides match, is 500 requests per one second (1s). Two overrides are also defined:

      • The first is 1 request (the maxAmount field) every 5s (the validDuration field), if the destination is reviews.
      • The second is 500 requests every 1s, if the destination is productpage and source is 10.28.11.20
      • The third is 2 requests every 5s, if the destination is productpage.

      When a request is processed, the first matching override is picked (reading from top to bottom).

      Or

      Run the following command to enable rate limits using redisquota:

      Zip

      1. $ kubectl apply -f @samples/bookinfo/policy/mixer-rule-productpage-redis-quota-rolling-window.yaml@

      Note: Replace , redis_server_url with values for your configuration.

      • The first is 1 request (the maxAmount field), if the destination is reviews.
      • The second is 500, if the destination is productpage and source is 10.28.11.20
      • The third is 2, if the destination is productpage.

      When a request is processed, the first matching override is picked (reading from top to bottom).

    2. Confirm the quota instance was created:

      The quota template defines three dimensions that are used by memquota or redisquota to set overrides on requests that match certain attributes. The destination will be set to the first non-empty value in destination.labels["app"], destination.service.host, or "unknown". For more information on expressions, see .

    3. Confirm the quota rule was created:

      1. $ kubectl -n istio-system get rule quota -o yaml

      The rule tells Mixer to invoke the memquota or redisquota handler (created above) and pass it the object constructed using the instance requestcountquota (also created above). This maps the dimensions from the quota template to memquota or redisquota handler.

    4. Confirm the QuotaSpec was created:

        This QuotaSpec defines the requestcountquota you created above with a charge of 1.

      1. Confirm the QuotaSpecBinding was created:

        1. $ kubectl -n istio-system get QuotaSpecBinding request-count -o yaml

        This QuotaSpecBinding binds the QuotaSpec you created above to the services you want to apply it to. productpage is explicitly bound to request-count, note that you must define the namespace since it differs from the namespace of the QuotaSpecBinding. If the last line is uncommented, binds all services to the QuotaSpec making the first entry redundant.

      2. Refresh the product page in your browser.

        request-count quota applies to productpage and it permits 2 requests every 5 seconds. If you keep refreshing the page you should see RESOURCE_EXHAUSTED:Quota is exhausted for: requestcount.

      In the above example we have effectively rate limited productpage at 2 rps per client IP. Consider a scenario where you would like to exempt clients from this rate limit if a user is logged in. In the bookinfo example, we use cookie session=<sessionid> to denote a logged in user. In a realistic scenario you may use a jwt token for this purpose.

      You can update the quota rule by adding a match condition based on the cookie.

      1. ...
      2. spec:
      3.   match: match(request.headers["cookie"], "session=*") == false
      4.   actions:
      5. ...

      Don’t enable chrome preload as it can preload cookies and fail this task.

      memquota or redisquota adapter is now dispatched only if session=<sessionid> cookie is absent from the request. This ensures that a logged in user is not subject to this quota.

      1. Verify that rate limit does not apply to a logged in user.

        Log in as jason and repeatedly refresh the productpage. Now you should be able to do this without a problem.

      2. Verify that rate limit does apply when not logged in.

        Logout as jason and repeatedly refresh the productpage. You should again see RESOURCE_EXHAUSTED:Quota is exhausted for: requestcount.

      Understanding rate limits

      In the preceding examples you saw how Mixer applies rate limits to requests that match certain conditions.

      Every named quota instance like requestcount represents a set of counters. The set is defined by a Cartesian product of all quota dimensions. If the number of requests in the last expiration duration exceed maxAmount, Mixer returns a RESOURCE_EXHAUSTED message to the Envoy proxy, and Envoy returns status HTTP 429 to the caller.

      The memquota adapter uses a sliding window of sub-second resolution to enforce rate limits.

      The maxAmount in the adapter configuration sets the default limit for all counters associated with a quota instance. This default limit applies if a quota override does not match the request. The memquota/redisquota adapter selects the first override that matches a request. An override need not specify all quota dimensions. In the example, the 0.2 qps override is selected by matching only three out of four quota dimensions.

      If you want the policies enforced for a given namespace instead of the entire Istio mesh, you can replace all occurrences of istio-system with the given namespace.

      1. If using memquota, remove the memquota rate limit configuration:

        Zip

        1. $ kubectl delete -f @samples/bookinfo/policy/mixer-rule-productpage-ratelimit.yaml@

        If you are using Istio 1.1.2 or prior:

        1. $ kubectl delete -f @samples/bookinfo/policy/mixer-rule-productpage-ratelimit-crd.yaml@

        Or

        If using redisquota, remove the redisquota rate limit configuration:

        Zip

      2. Remove the application routing rules:

      3. If you are not planning to explore any follow-on tasks, refer to the Bookinfo cleanup instructions to shutdown the application.

      See also

      App Identity and Access Adapter

      Using Istio to secure multi-cloud Kubernetes applications with zero code changes.

      Improving availability and reducing latency.

      Mixer Adapter Model

      Provides an overview of Mixer’s plug-in architecture.

      Shows how to modify request headers and routing using policy adapters.

      Denials and White/Black Listing (Deprecated)

      Shows how to control access to a service using simple denials or white/black listing.

      This task shows you how to enable Istio policy enforcement.