MeshRateLimit

This policy enables per-instance service request limiting. Policy supports rate limiting of HTTP/HTTP2 requests and TCP connections.

The MeshRateLimit policy leverages Envoy’s local rate limiting for HTTP/HTTP2 and local rate limit filter for TCP connections.

You can configure:

• how many HTTP requests are allowed in a specified time period
• how the HTTP service responds when the limit is reached
• how many TCP connections are allowed in a specified time period

The policy is applied per service instance. This means that if a service backend has 3 instances rate limited to 100 requests per second, the overall service rate limit is 300 requests per second.

Rate limiting supports an ExternalService only when ZoneEgress is enabled.

TargetRef support matrix

To learn more about the information in this table, see the matching docs.

Configuration

The MeshRateLimit policy supports both L4/TCP and L7/HTTP limiting. Envoy implements Token Bucket algorithm for rate limiting.

HTTP Rate limiting

• disabled - (optional) - should rate limiting policy be disabled
• requestRate - configuration of the number of requests in the specific time window
  • num - the number of requests to limit
  • interval - the interval for which requests will be limited
• onRateLimit (optional) - actions to take on RateLimit event
  • status (optional) - the status code to return, defaults to 429
  • headers - (optional) headers which should be added to every rate limited response

Headers

• set - (optional) - list of headers to set. Overrides value if the header exists.
  • name - header’s name
  • value - header’s value
• add - (optional) - list of headers to add. Appends value if the header exists.
  • name - header’s name
  • value - header’s value

TCP Rate limiting

TCP rate limiting allows the configuration of a number of connections in the specific time window

• disabled - (optional) - should rate limiting policy be disabled
• connectionRate - configuration of the number of connections in the specific time window
  • num - the number of requests to limit
  • interval - the interval for which connections will be limited

Examples

HTTP Rate limit configured for service backend from all services in the Mesh

apiVersion: kuma.io/v1alpha1
kind: MeshRateLimit
metadata:
  name: backend-rate-limit
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: Dataplane
    labels:
      app: backend
  rules:
  - default:
      local:
        http:
          requestRate:
            num: 5
            interval: 10s
          onRateLimit:
            status: 423
            headers:
              set:
              - name: x-kuma-rate-limited
                value: 'true'

type: MeshRateLimit
mesh: default
name: backend-rate-limit
spec:
  targetRef:
    kind: Dataplane
    labels:
      app: backend
  rules:
  - default:
      local:
        http:
          requestRate:
            num: 5
            interval: 10s
          onRateLimit:
            status: 423
            headers:
              set:
              - name: x-kuma-rate-limited
                value: 'true'

TCP rate limit for service backend from all services in the Mesh

apiVersion: kuma.io/v1alpha1
kind: MeshRateLimit
metadata:
  name: backend-rate-limit
  namespace: kuma-demo
  labels:
    kuma.io/mesh: default
spec:
  targetRef:
    kind: Dataplane
    labels:
      app: backend
  rules:
  - default:
      local:
        tcp:
          connectionRate:
            num: 5
            interval: 10s

type: MeshRateLimit
name: backend-rate-limit
mesh: default
spec:
  targetRef:
    kind: Dataplane
    labels:
      app: backend
  rules:
  - default:
      local:
        tcp:
          connectionRate:
            num: 5
            interval: 10s

See also

• MeshCircuitBreaker - Prevent cascading failures and overload
• MeshTimeout - Configure request timeouts
• MeshHealthCheck - Monitor service health

All policy options