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Rate Limiting

You are browsing documentation for an outdated plugin version. See the latest documentation here.

Rate limit how many HTTP requests a developer can make in a given period of seconds, minutes, hours, days, months or years. If the underlying Service/Route (or deprecated API entity) has no authentication layer, the Client IP address will be used, otherwise the Consumer will be used if an authentication plugin has been configured.

Note: The functionality of this plugin as bundled with versions of Kong prior to 0.13.1 and Kong Gateway prior to 0.32 differs from what is documented herein. Refer to the CHANGELOG for details.

Configuration Reference

This plugin is partially compatible with DB-less mode.

In DB-less mode, you configure Kong Gateway declaratively. Therefore, the Admin API is mostly read-only. The only tasks it can perform are all related to handling the declarative config, including:

  • Setting a target's health status in the load balancer
  • Validating configurations against schemas
  • Uploading the declarative configuration using the /config endpoint

The plugin will run fine with the local policy (which doesn’t use the database) or the redis policy (which uses an independent Redis, so it is compatible with DB-less).

The plugin will not work with the cluster policy, which requires writes to the database.

Example plugin configuration

The following examples provide some typical configurations for enabling the rate-limiting plugin on a service.

Make the following request:

curl -X POST http://localhost:8001/services/SERVICE_NAME|SERVICE_ID/plugins \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local"

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: rate-limiting-example
config: 
  second: 5
  hour: 10000
  policy: local
plugin: rate-limiting

Next, apply the KongPlugin resource to a service by annotating the service as follows:

apiVersion: v1
kind: Service
metadata:
  name: SERVICE_NAME|SERVICE_ID
  labels:
    app: SERVICE_NAME|SERVICE_ID
  annotations:
    konghq.com/plugins: rate-limiting-example
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: SERVICE_NAME|SERVICE_ID
  selector:
    app: SERVICE_NAME|SERVICE_ID

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

Note: The KongPlugin resource only needs to be defined once and can be applied to any service, consumer, or route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

Add this section to your declarative configuration file:

plugins:
- name: rate-limiting
  service: SERVICE_NAME|SERVICE_ID
  config: 
    second: 5
    hour: 10000
    policy: local

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

You can configure this plugin through the Konnect UI.

From the servicehub icon Service Hub, select a service version, then set up the plugin:

  1. In the Plugins section, click Add Plugin.
  2. Find and select the Rate Limiting plugin.
  3. Click Create.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. From the Services section, click View for the service row.
  3. From the plugin section, click Add Plugin.
  4. Find and select the Rate Limiting plugin.
  5. If the option is available, select Scoped.
  6. Add the service name and ID to the Service field if it is not already pre-filled.
  7. Click Create.

The following examples provide some typical configurations for enabling the rate-limiting plugin on a route.

Make the following request:

$ curl -X POST http://localhost:8001/routes/ROUTE_NAME|ROUTE_ID/plugins \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local"

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: rate-limiting-example
config: 
  second: 5
  hour: 10000
  policy: local
plugin: rate-limiting

Then, apply it to an ingress (route or routes) by annotating the ingress as follows:

apiVersion: networking/v1beta1
kind: Ingress
metadata:
  name: ROUTE_NAME|ROUTE_ID
  annotations:
    kubernetes.io/ingress.class: kong
    konghq.com/plugins: rate-limiting-example
spec:
  rules:
  - host: examplehostname.com
    http:
      paths:
      - path: /bar
        backend:
          serviceName: echo
          servicePort: 80

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

Note: The KongPlugin resource only needs to be defined once and can be applied to any service, consumer, or route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

Add this section to your declarative configuration file:

plugins:
- name: rate-limiting
  route: ROUTE_NAME
  config: 
    second: 5
    hour: 10000
    policy: local

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

You can configure this plugin through the Konnect UI.

From the servicehub icon Service Hub, select a service version, then set up the plugin:

  1. Select a route.
  2. In the Plugins section, click Add Plugin.
  3. Find and select the Rate Limiting plugin.
  4. Click Create.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. Open Routes from the menu, then click View for the route row.
  3. From the plugin section, click Add Plugin.
  4. Find and select the Rate Limiting plugin.
  5. If the option is available, select Scoped.
  6. Add the route ID if it is not already prefilled.
  7. Click Create.

The following examples provide some typical configurations for enabling the rate-limiting plugin on a consumer.

Make the following request:

$ curl -X POST http://localhost:8001/consumers/CONSUMER_NAME|CONSUMER_ID/plugins \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local"

Replace CONSUMER_NAME|CONSUMER_ID with the id or name of the consumer that this plugin configuration will target.

You can combine consumer.id, service.id, or route.id in the same request, to further narrow the scope of the plugin.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: rate-limiting-example
config: 
  second: 5
  hour: 10000
  policy: local
plugin: rate-limiting

Then, apply it to a consumer by annotating the KongConsumer resource as follows:

apiVersion: configuration.konghq.com/v1
kind: KongConsumer
metadata:
  name: CONSUMER_NAME|CONSUMER_ID
  annotations:
    konghq.com/plugins: rate-limiting-example
    kubernetes.io/ingress.class: kong

Replace CONSUMER_NAME|CONSUMER_ID with the id or name of the consumer that this plugin configuration will target.

Note: The KongPlugin resource only needs to be defined once and can be applied to any service, consumer, or route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

Add this section to your declarative configuration file:

plugins:
- name: rate-limiting
  consumer: CONSUMER_NAME|CONSUMER_ID
  config: 
    second: 5
    hour: 10000
    policy: local

Replace CONSUMER_NAME|CONSUMER_ID with the id or name of the consumer that this plugin configuration will target.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. From the Consumers section, click View for the consumer row.
  3. Select the Plugins tab, then click Add Plugin.
  4. Find and select the Rate Limiting plugin.
  5. If the option is available, select Scoped.
  6. Add the consumer ID if it is not already prefilled.
  7. Click Create.

A plugin which is not associated to any service, route, or consumer is considered global, and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

The following examples provide some typical configurations for enabling the rate-limiting plugin globally.

Make the following request:

$ curl -X POST http://localhost:8001/plugins/ \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local"

Create a KongClusterPlugin resource and label it as global:

apiVersion: configuration.konghq.com/v1
kind: KongClusterPlugin
metadata:
  name: <global-rate-limiting>
  annotations:
    kubernetes.io/ingress.class: kong
  labels:
    global: \"true\"
config: 
  second: 5
  hour: 10000
  policy: local
plugin: rate-limiting

Add a plugins entry in the declarative configuration file:

plugins:
- name: rate-limiting
  config: 
    second: 5
    hour: 10000
    policy: local

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. Open Plugins from the menu, then click New Plugin.
  3. Find and select the Rate Limiting plugin.
  4. If the option is available, set the plugin scope to Global.
  5. Click Create.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

Form Parameter Description
name
required

Type: string		 The name of the plugin, in this case rate-limiting.
service.name or service.id

Type: string		 The name or ID of the service the plugin targets.

Set one of these parameters if adding the plugin to a service through the top-level /plugins endpoint.

Not required if using /services/SERVICE_NAME|SERVICE_ID/plugins.
route.name or route.id

Type: string		 The name or ID of the route the plugin targets.

Set one of these parameters if adding the plugin to a route through the top-level /plugins endpoint.

Not required if using /routes/ROUTE_NAME|ROUTE_ID/plugins.
consumer.name or consumer.id

Type: string		 The name or ID of the consumer the plugin targets.

Set one of these parameters if adding the plugin to a consumer through the top-level /plugins endpoint.

Not required if using /consumers/CONSUMER_NAME|CONSUMER_ID/plugins.
enabled

Type: boolean

Default value: true		 Whether this plugin will be applied.
config.second
semi-optional

The amount of HTTP requests the developer can make per second. At least one limit must exist.
config.minute
semi-optional

The amount of HTTP requests the developer can make per minute. At least one limit must exist.
config.hour
semi-optional

The amount of HTTP requests the developer can make per hour. At least one limit must exist.
config.day
semi-optional

The amount of HTTP requests the developer can make per day. At least one limit must exist.
config.month
semi-optional

The amount of HTTP requests the developer can make per month. At least one limit must exist.
config.year
semi-optional

The amount of HTTP requests the developer can make per year. At least one limit must exist.
config.limit_by
optional

Default value: consumer

The entity that will be used when aggregating the limits: consumer, credential, ip, service, header. If the consumer, the credential or the service cannot be determined, the system will always fallback to ip.
config.service_id
semi-optional

The service id to be used if limit_by is set to service.
config.header_name
semi-optional

Header name to be used if limit_by is set to header.
config.policy
optional

Default value: cluster

The rate-limiting policies to use for retrieving and incrementing the limits. Available values are local (counters will be stored locally in-memory on the node), cluster (counters are stored in the datastore and shared across the nodes) and redis (counters are stored on a Redis server and will be shared across the nodes). In case of DB-less mode, at least one of local or redis must be specified. Please refer Implementation Considerations for details on which policy should be used.
config.fault_tolerant
optional

Default value: true

A boolean value that determines if the requests should be proxied even if Kong has troubles connecting a third-party datastore. If true requests will be proxied anyways effectively disabling the rate-limiting function until the datastore is working again. If false then the clients will see 500 errors.
config.hide_client_headers
optional

Default value: false

Optionally hide informative response headers.
config.redis_host
semi-optional

When using the redis policy, this property specifies the address to the Redis server.
config.redis_port
optional

Default value: 6379

When using the redis policy, this property specifies the port of the Redis server. By default is 6379.
config.redis_password
optional

When using the redis policy, this property specifies the password to connect to the Redis server.
config.redis_timeout
optional

Default value: 2000

When using the redis policy, this property specifies the timeout in milliseconds of any command submitted to the Redis server.
config.redis_database
optional

Default value: 0

When using the redis policy, this property specifies Redis database to use.

Headers sent to the client

When this plugin is enabled, Kong will send some additional headers back to the client telling what are the limits allowed, how many requests are available and how long it will take until the quota will be restored, for example:

RateLimit-Limit: 6
RateLimit-Remaining: 4
RateLimit-Reset: 47

The plugin will also send headers telling the limits in the time frame and the number of requests remaining:

X-RateLimit-Limit-Minute: 10
X-RateLimit-Remaining-Minute: 9

or it will return a combination of more time limits, if more than one is being set:

X-RateLimit-Limit-Second: 5
X-RateLimit-Remaining-Second: 4
X-RateLimit-Limit-Minute: 10
X-RateLimit-Remaining-Minute: 9

If any of the limits configured is being reached, the plugin will return a HTTP/1.1 429 status code to the client with the following JSON body:

{ "message": "API rate limit exceeded" }

NOTE:

The headers `RateLimit-Limit`, `RateLimit-Remaining` and `RateLimit-Reset` are based on the Internet-Draft RateLimit Header Fields for HTTP and may change in the future, respecting updates to the specification.

Implementation considerations

The plugin supports 3 policies, which each have their specific pros and cons.

policy pros cons
cluster accurate, no extra components to support relatively the biggest performance impact, each request forces a read and a write on the underlying datastore.
redis accurate, lesser performance impact than a cluster policy extra redis installation required, bigger performance impact than a local policy
local minimal performance impact less accurate, and unless a consistent-hashing load balancer is used in front of Kong, it diverges when scaling the number of nodes

There are 2 use cases that are most common:

  1. every transaction counts. These are for example transactions with financial consequences. Here the highest level of accuracy is required.
  2. backend protection. This is where accuracy is not as relevant, but it is merely used to protect backend services from overload. Either by specific users, or to protect against an attack in general.

NOTE:

Enterprise-Only The Kong Community Edition of this Rate Limiting plugin does not include Redis Sentinel support. Kong Gateway Subscription customers have the option of using Redis Sentinel with Kong Rate Limiting to deliver highly available primary-replica deployments.

Every transaction counts

In this scenario, the local policy is not an option. So here the decision is between the extra performance of the redis policy against its extra support effort. Based on that balance, the choice should either be cluster or redis.

The recommendation is to start with the cluster policy, with the option to move over to redis if performance reduces drastically. Keep in mind existing usage metrics cannot be ported from the datastore to redis. Generally with shortlived metrics (per second or per minute) this is not an issue, but with longer lived ones (months) it might be, so you might want to plan your switch more carefully.

Backend protection

As accuracy is of lesser importance, the local policy can be used. It might require some experimenting to get the proper setting. For example, if the user is bound to 100 requests per second, and you have an equally balanced 5 node Kong cluster, setting the local limit to something like 30 requests per second should work. If you are worried about too many false-negatives, increase the value.

Keep in mind as the cluster scales to more nodes, the users will get more requests granted, and likewise when the cluster scales down the probability of false-negatives increases. So in general, update your limits when scaling.

The above mentioned inaccuracy can be mitigated by using a consistent-hashing load balancer in front of Kong, that ensures the same user is always directed to the same Kong node. This will both reduce the inaccuracy and prevent the scaling issues.

Most likely the user will be granted more than was agreed when using the local policy, but it will effectively block any attacks while maintaining the best performance.