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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You are browsing documentation for an outdated plugin version.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 can be made 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.

Tip: The Rate Limiting Advanced plugin provides the ability to apply multiple limits in sliding or fixed windows.

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.

Enable the plugin on a service

For example, configure this plugin on a service by making the following request:

curl -X POST http://{HOST}:8001/services/{SERVICE}/plugins \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local" \
    --data "config.fault_tolerant=true" \
    --data "config.hide_client_headers=false"

SERVICE is 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
  fault_tolerant: true
  hide_client_headers: false
plugin: rate-limiting

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

apiVersion: v1
kind: Service
metadata:
  name: {SERVICE}
  labels:
    app: {SERVICE}
  annotations:
    konghq.com/plugins: <rate-limiting-example>
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: {SERVICE}
  selector:
    app: {SERVICE}

{SERVICE} is 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.

For example, configure this plugin on a service by adding this section to your declarative configuration file:

plugins:
- name: rate-limiting
  service: {SERVICE}
  config: 
    second: 5
    hour: 10000
    policy: local
    fault_tolerant: true
    hide_client_headers: false

SERVICE is the id or name of the service that this plugin configuration will target.

Configure this plugin on a service:

  1. In Konnect Cloud, select the service on the ServiceHub page.
  2. Scroll down to Versions and select the version.
  3. Scroll down to Plugins and click New Plugin.
  4. Find and select the Rate Limiting plugin.

  5. Enter the following parameters, updating the default or sample values as needed:

    • Config.Fault Tolerant: select checkbox
    • Config.Hide Client Headers: clear checkbox
  6. Click Create.

Configure this plugin on a service:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, scroll down to Services and click View for the service row.
  3. Scroll down to plugins and click Add Plugin.

  4. Find and select the Rate Limiting plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  5. If the option is available, select Scoped.
  6. Add the service name and ID to the Service field if it is not already prefilled.

  7. Enter the following parameters, updating the default or sample values as needed:

    • Config.Fault Tolerant: select checkbox
    • Config.Hide Client Headers: clear checkbox
  8. Click Create.

Enable the plugin on a route

For example, configure this plugin on a route with:

$ curl -X POST http://{HOST}:8001/routes/{ROUTE}/plugins \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local" \
    --data "config.fault_tolerant=true" \
    --data "config.hide_client_headers=false"

ROUTE is 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
  fault_tolerant: true
  hide_client_headers: false
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}
  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

ROUTE is 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.

For example, configure this plugin on a route by adding this section to your declarative configuration file:

plugins:
- name: rate-limiting
  route: <route>
  config: 
    second: 5
    hour: 10000
    policy: local
    fault_tolerant: true
    hide_client_headers: false

ROUTE is the id or name of the route that this plugin configuration will target.

Configure this plugin on a route:

  1. In Konnect Cloud, select the service from the ServiceHub page.
  2. Scroll down to Versions and select the version.
  3. Select the route.
  4. Scroll down to Plugins and click Add Plugin.
  5. Find and select the Rate Limiting plugin.

  6. Enter the following parameters, updating the default or sample values as needed:

    • Config.Fault Tolerant: select checkbox
    • Config.Hide Client Headers: clear checkbox
  7. Click Create.

Configure this plugin on a route:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, select Routes in the left navigation.
  3. Click View for the route row.
  4. Scroll down to plugins and click Add Plugin.

  5. Find and select the Rate Limiting plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  6. If the option is available, select Scoped.
  7. Add the Route ID if it is not already prefilled.

  8. Enter the following parameters, updating the default or sample values as needed:

    • Config.Fault Tolerant: select checkbox
    • Config.Hide Client Headers: clear checkbox
  9. Click Create.

Enabling the plugin on a consumer

For example, configure this plugin on a consumer with:

$ curl -X POST http://{HOST}:8001/consumers/{CONSUMER}/plugins \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local" \
    --data "config.fault_tolerant=true" \
    --data "config.hide_client_headers=false"

CONSUMER is the id or username 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
  fault_tolerant: true
  hide_client_headers: false
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}
  annotations:
    konghq.com/plugins: <rate-limiting-example>
    kubernetes.io/ingress.class: kong

CONSUMER is the id or username 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.

For example, configure this plugin on a consumer by adding this section to your declarative configuration file:

plugins:
- name: rate-limiting
  consumer: {CONSUMER}
  config: 
    second: 5
    hour: 10000
    policy: local
    fault_tolerant: true
    hide_client_headers: false

CONSUMER is the id or username of the consumer that this plugin configuration will target.

Configure this plugin on a consumer:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, scroll down to Consumers and click View for the consumer row.
  3. Select the Plugins tab.
  4. Click Add Plugin.

  5. Find and select the Rate Limiting plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  6. If the option is available, select Global.

  7. Enter the following parameters, updating the default or sample values as needed:

    • Config.Fault Tolerant: select checkbox
    • Config.Hide Client Headers: clear checkbox
  8. Click Create.

Enable the plugin globally

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.

For example, configure this plugin globally with:

$ curl -X POST http://{HOST}:8001/plugins/ \
    --data "name=rate-limiting"  \
    --data "config.second=5" \
    --data "config.hour=10000" \
    --data "config.policy=local" \
    --data "config.fault_tolerant=true" \
    --data "config.hide_client_headers=false"

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
  fault_tolerant: true
  hide_client_headers: false
plugin: rate-limiting

For example, configure this plugin using the plugins: entry in the declarative configuration file:

plugins:
- name: rate-limiting
  config: 
    second: 5
    hour: 10000
    policy: local
    fault_tolerant: true
    hide_client_headers: false

Configure this plugin globally:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, select Plugins in the left navigation.
  3. Click New Plugin.

  4. Find and select the Rate Limiting plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  5. If the option is available, set the plugin scope to Global.

  6. Enter the following parameters, updating the default/sample values as needed:

    • Config.Fault Tolerant: select checkbox
    • Config.Hide Client Headers: clear checkbox
  7. 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.id

Type: string		 The ID of the Service the plugin targets.
route.id

Type: string		 The ID of the Route the plugin targets.
consumer.id

Type: string		 The ID of the Consumer the plugin targets.
enabled
required

Type: boolean

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

Type: number

The number of HTTP requests that can be made per second.
config.minute
semi-optional

Type: number

The number of HTTP requests that can be made per minute.
config.hour
semi-optional

Type: number

The number of HTTP requests that can be made per hour.
config.day
semi-optional

Type: number

The number of HTTP requests that can be made per day.
config.month
semi-optional

Type: number

The number of HTTP requests that can be made per month.
config.year
semi-optional

Type: number

The number of HTTP requests that can be made per year.
config.limit_by
optional

Type: string

Default value: consumer

The entity that will be used when aggregating the limits: consumer, credential, ip, service, header, path. If the value for the entity chosen to aggregate the limit cannot be determined, the system will always fallback to ip. If value service is chosen, the service_id configuration must be provided. If value header is chosen, the header_name configuration must be provided. If value path is chosen, the path configuration must be provided.
config.service_id
semi-optional

Type: string

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

Type: string

Header name to be used if limit_by is set to header.
config.path
semi-optional

Type: string

Path to be used if limit_by is set to path.
config.policy
optional

Type: string

Default value: cluster

The rate-limiting policies to use for retrieving and incrementing the limits. Available values are:

  • local: Counters are stored locally in-memory on the node.
  • cluster: Counters are stored in the Kong datastore and shared across the nodes.
  • redis: Counters are stored on a Redis server and shared across the nodes.

In DB-less and hybrid modes, the cluster config policy is not supported. For DB-less mode, use one of redis or local; for hybrid mode, use redis, or local for data planes only.

In Konnect Cloud, the default policy is redis.

For details on which policy should be used, refer to the implementation considerations.
config.fault_tolerant
required

Type: boolean

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 anyway, 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
required

Type: boolean

Default value: false

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

Type: string

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

Type: integer

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

Type: string

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

Type: number

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

Type: integer

Default value: 0

When using the redis policy, this property specifies the Redis database to use.
Note: At least one limit (`second`, `minute`, `hour`, `day`, `month`, `year`) must be configured. Multiple limits can be configured.

Headers sent to the client

When this plugin is enabled, Kong sends additional headers to show the allowed limits, number of available requests, and the time remaining (in seconds) until the quota is reset. Here’s an example header:

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

The plugin also sends headers to show the time limit and the minutes still available:

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

If more than one time limit is set, the header contains all of these:

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

When a limit is reached, the plugin returns an HTTP/1.1 429 status code, with the following JSON body:

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

Warning: The headers RateLimit-Limit, RateLimit-Remaining, and RateLimit-Reset are based on the Internet-Draft RateLimit Header Fields for HTTP. These could change if the specification is updated.

Implementation considerations

The plugin supports three policies.

Policy Pros Cons
cluster Accurate, no extra components to support. Each request forces a read and a write on the datastore. Therefore, relatively, the biggest performance impact.
redis Accurate, less performance impact than a cluster policy. Needs a Redis installation. Bigger performance impact than a local policy.
local Minimal performance impact. Less accurate. Unless there’s a consistent-hashing load balancer in front of Kong, it diverges when scaling the number of nodes.

Two common use cases are:

  1. Every transaction counts. The highest level of accuracy is needed. An example is a transaction with financial consequences.
  2. Backend protection. Accuracy is not as relevant. The requirement is only to protect backend services from overloading that’s caused either by specific users or by attacks.

Note: Enterprise-Only: The Kong Community Edition of this Rate Limiting plugin does not include Redis Sentinel support. Only Kong Gateway Subscription customers can use Redis Sentinel with Kong Rate Limiting, enabling them to deliver highly available primary-replica deployments.

Every transaction counts

In this scenario, because accuracy is important, the local policy is not an option. Consider the support effort you might need for Redis, and then choose either cluster or redis.

You could start with the cluster policy, and move to redis if performance reduces drastically.

Do remember that you cannot port the existing usage metrics from the datastore to Redis. This might not be a problem with shortlived metrics (for example, seconds or minutes) but if you use metrics with a longer time frame (for example, months), plan your switch carefully.

Backend protection

If accuracy is of lesser importance, choose the local policy. You might need to experiment a little before you get a setting that works for your scenario. As the cluster scales to more nodes, more user requests are handled. When the cluster scales down, the probability of false negatives increases. So, adjust your limits when scaling.

For example, if a user can make 100 requests every second, and you have an equally balanced 5-node Kong cluster, setting the local limit to something like 30 requests every second should work. If you see too many false negatives, increase the limit.

To minimise inaccuracies, consider using a consistent-hashing load balancer in front of Kong. The load balancer ensures that a user is always directed to the same Kong node, thus reducing inaccuracies and preventing scaling problems.

Fallback to IP

When the selected policy cannot be retrieved, the plugin falls back to limiting usage by identifying the IP address. This can happen for several reasons, such as the selected header was not sent by the client or the configured service was not found.