Rate Limit
Rate Limit is an inbound policy. Dataplanes whose configuration is modified are in the destinations
matcher.
The RateLimit
policy leverages Envoy’s local rate limiting to allow for per-instance service request limiting. All HTTP/HTTP2 based requests are supported.
You can configure how many requests are allowed in a specified time period, and how the service responds when the limit is reached.
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 is rate limited to 300 requests per second.
When rate limiting to an ExternalService, the policy is applied per sending service instance.`
Usage
apiVersion: kuma.io/v1alpha1
kind: RateLimit
mesh: default
metadata:
name: rate-limit-all-to-backend
spec:
sources:
- match:
kuma.io/service: "*"
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
requests: 5
interval: 10s
onRateLimit:
status: 423
headers:
- key: "x-kuma-rate-limited"
value: "true"
append: true
Apply the configuration with kubectl apply -f [..]
.
type: RateLimit
mesh: default
name: rate-limit-all-to-backend
sources:
- match:
kuma.io/service: "*"
destinations:
- match:
kuma.io/service: backend
conf:
http:
requests: 5
interval: 10s
onRateLimit:
status: 423
headers:
- key: "x-kuma-rate-limited"
value: "true"
append: true
Apply the configuration with kumactl apply -f [..]
or with the HTTP API.
Configuration fields
The conf
section of the RateLimit
resource provides the following configuration options:
http
-requests
- the number of requests to limitinterval
- the interval for whichrequests
will be limitedonRateLimit
(optional) - actions to take on RateLimit eventstatus
(optional) - the status code to return, defaults to429
headers
- list of headers which should be added to every rate limited response:key
- the name of the headervalue
- the value of the headerappend
(optional) - should the value of the provided header be appended to already existing headers (if present)
Matching sources
This policy is applied on the destination data plane proxy and generates a set of matching rules for the originating service. These matching rules are ordered from the most specific one, to the more generic ones. Given the following RateLimit
resources:
apiVersion: kuma.io/v1alpha1
kind: RateLimit
mesh: default
metadata:
name: rate-limit-all-to-backend
spec:
sources:
- match:
kuma.io/service: "*"
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
requests: 5
interval: 10s
---
apiVersion: kuma.io/v1alpha1
kind: RateLimit
mesh: default
metadata:
name: rate-limit-frontend
spec:
sources:
- match:
kuma.io/service: "frontend_default_svc_80"
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
requests: 10
interval: 10s
---
apiVersion: kuma.io/v1alpha1
kind: RateLimit
mesh: default
metadata:
name: rate-limit-frontend-zone-eu
spec:
sources:
- match:
kuma.io/service: "frontend_default_svc_80"
kuma.io/zone: "eu"
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
requests: 20
interval: 10s
The service backend
is configured with the following rate limiting hierarchy:
rate-limit-frontend-zone-eu
rate-limit-frontend
rate-limit-all-to-backend
Matching destinations
RateLimit
, when applied to a dataplane proxy bound Kuma service, is an Inbound Connection Policy.
When applied to an ExternalService, RateLimit
is an Outbound Connection Policy. In this case, the only supported value for destinations.match
is kuma.io/service
.
Builtin Gateway support
Kuma Gateway supports the RateLimit
connection policy. Rate limits are configured on each Envoy route by selecting the best Rate Limit policy that matches the source and destination.