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RateLimit

To Control the Number of Requests Going to a Service

The RateLimit middleware ensures that services will receive a fair amount of requests, and allows one to define what fair is.

Configuration Example

# Here, an average of 100 requests per second is allowed.
# In addition, a burst of 50 requests is allowed.
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.average=100"
  - "traefik.http.middlewares.test-ratelimit.ratelimit.burst=50"
# Here, an average of 100 requests per second is allowed.
# In addition, a burst of 50 requests is allowed.
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    average: 100
    burst: 50
# Here, an average of 100 requests per second is allowed.
# In addition, a burst of 50 requests is allowed.
- "traefik.http.middlewares.test-ratelimit.ratelimit.average=100"
- "traefik.http.middlewares.test-ratelimit.ratelimit.burst=50"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.average": "100",
  "traefik.http.middlewares.test-ratelimit.ratelimit.burst": "50"
}
# Here, an average of 100 requests per second is allowed.
# In addition, a burst of 50 requests is allowed.
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.average=100"
  - "traefik.http.middlewares.test-ratelimit.ratelimit.burst=50"
# Here, an average of 100 requests per second is allowed.
# In addition, a burst of 50 requests is allowed.
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    average = 100
    burst = 50
# Here, an average of 100 requests per second is allowed.
# In addition, a burst of 50 requests is allowed.
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        average: 100
        burst: 50

Configuration Options

average

average is the maximum rate, by default in requests per second, allowed from a given source.

It defaults to 0, which means no rate limiting.

The rate is actually defined by dividing average by period. So for a rate below 1 req/s, one needs to define a period larger than a second.

# 100 reqs/s
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.average=100"
# 100 reqs/s
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    average: 100
# 100 reqs/s
- "traefik.http.middlewares.test-ratelimit.ratelimit.average=100"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.average": "100",
}
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.average=100"
# 100 reqs/s
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    average = 100
# 100 reqs/s
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        average: 100

period

period, in combination with average, defines the actual maximum rate, such as:

r = average / period

It defaults to 1 second.

# 6 reqs/minute
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.average=6"
  - "traefik.http.middlewares.test-ratelimit.ratelimit.period=1m"
# 6 reqs/minute
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    period: 1m
    average: 6
# 6 reqs/minute
- "traefik.http.middlewares.test-ratelimit.ratelimit.average=6"
- "traefik.http.middlewares.test-ratelimit.ratelimit.period=1m"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.average": "6",
  "traefik.http.middlewares.test-ratelimit.ratelimit.period": "1m",
}
# 6 reqs/minute
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.average=6"
  - "traefik.http.middlewares.test-ratelimit.ratelimit.period=1m"
# 6 reqs/minute
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    average = 6
    period = "1m"
# 6 reqs/minute
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        average: 6
        period: 1m

burst

burst is the maximum number of requests allowed to go through in the same arbitrarily small period of time.

It defaults to 1.

labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.burst=100"
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    burst: 100
- "traefik.http.middlewares.test-ratelimit.ratelimit.burst=100"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.burst": "100",
}
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.burst=100"
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    burst = 100
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        burst: 100

sourceCriterion

The sourceCriterion option defines what criterion is used to group requests as originating from a common source. The precedence order is ipStrategy, then requestHeaderName, then requestHost. If none are set, the default is to use the request's remote address field (as an ipStrategy).

sourceCriterion.ipStrategy

The ipStrategy option defines two parameters that configures how Traefik determines the client IP: depth, and excludedIPs.

ipStrategy.depth

The depth option tells Traefik to use the X-Forwarded-For header and select the IP located at the depth position (starting from the right).

  • If depth is greater than the total number of IPs in X-Forwarded-For, then the client IP is empty.
  • depth is ignored if its value is less than or equal to 0.

Example of Depth & X-Forwarded-For

If depth is set to 2, and the request X-Forwarded-For header is "10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" then the "real" client IP is "10.0.0.1" (at depth 4) but the IP used as the criterion is "12.0.0.1" (depth=2).

X-Forwarded-For depth clientIP
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" 1 "13.0.0.1"
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" 3 "11.0.0.1"
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" 5 ""
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.depth=2"
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    sourceCriterion:
      ipStrategy:
        depth: 2
- "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.depth=2"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.depth": "2"
}
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.depth=2"
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    [http.middlewares.test-ratelimit.rateLimit.sourceCriterion.ipStrategy]
      depth = 2
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        sourceCriterion:
          ipStrategy:
            depth: 2
ipStrategy.excludedIPs

Contrary to what the name might suggest, this option is not about excluding an IP from the rate limiter, and therefore cannot be used to deactivate rate limiting for some IPs.

If depth is specified, excludedIPs is ignored.

excludedIPs is meant to address two classes of somewhat distinct use-cases:

  1. Distinguish IPs which are behind the same (set of) reverse-proxies so that each of them contributes, independently to the others, to its own rate-limit "bucket" (cf the leaky bucket analogy). In this case, excludedIPs should be set to match the list of X-Forwarded-For IPs that are to be excluded, in order to find the actual clientIP.

    Each IP as a distinct source

    X-Forwarded-For excludedIPs clientIP
    "10.0.0.1,11.0.0.1,12.0.0.1" "11.0.0.1,12.0.0.1" "10.0.0.1"
    "10.0.0.2,11.0.0.1,12.0.0.1" "11.0.0.1,12.0.0.1" "10.0.0.2"
  2. Group together a set of IPs (also behind a common set of reverse-proxies) so that they are considered the same source, and all contribute to the same rate-limit bucket.

    Group IPs together as same source

    X-Forwarded-For excludedIPs clientIP
    "10.0.0.1,11.0.0.1,12.0.0.1" "12.0.0.1" "11.0.0.1"
    "10.0.0.2,11.0.0.1,12.0.0.1" "12.0.0.1" "11.0.0.1"
    "10.0.0.3,11.0.0.1,12.0.0.1" "12.0.0.1" "11.0.0.1"

For completeness, below are additional examples to illustrate how the matching works. For a given request the list of X-Forwarded-For IPs is checked from most recent to most distant against the excludedIPs pool, and the first IP that is not in the pool (if any) is returned.

Matching for clientIP

X-Forwarded-For excludedIPs clientIP
"10.0.0.1,11.0.0.1,13.0.0.1" "11.0.0.1" "13.0.0.1"
"10.0.0.1,11.0.0.1,13.0.0.1" "15.0.0.1,16.0.0.1" "13.0.0.1"
"10.0.0.1,11.0.0.1" "10.0.0.1,11.0.0.1" ""
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    sourceCriterion:
      ipStrategy:
        excludedIPs:
        - 127.0.0.1/32
        - 192.168.1.7
- "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.excludedips": "127.0.0.1/32, 192.168.1.7"
}
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    [http.middlewares.test-ratelimit.rateLimit.sourceCriterion.ipStrategy]
      excludedIPs = ["127.0.0.1/32", "192.168.1.7"]
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        sourceCriterion:
          ipStrategy:
            excludedIPs:
              - "127.0.0.1/32"
              - "192.168.1.7"

sourceCriterion.requestHeaderName

Name of the header used to group incoming requests.

labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requestheadername=username"
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    sourceCriterion:
      requestHeaderName: username
- "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requestheadername=username"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requestheadername": "username"
}
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requestheadername=username"
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    [http.middlewares.test-ratelimit.rateLimit.sourceCriterion]
      requestHeaderName = "username"
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        sourceCriterion:
          requestHeaderName: username

sourceCriterion.requestHost

Whether to consider the request host as the source.

labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requesthost=true"
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: test-ratelimit
spec:
  rateLimit:
    sourceCriterion:
      requestHost: true
- "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requesthost=true"
"labels": {
  "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requesthost": "true"
}
labels:
  - "traefik.http.middlewares.test-ratelimit.ratelimit.sourcecriterion.requesthost=true"
[http.middlewares]
  [http.middlewares.test-ratelimit.rateLimit]
    [http.middlewares.test-ratelimit.rateLimit.sourceCriterion]
      requestHost = true
http:
  middlewares:
    test-ratelimit:
      rateLimit:
        sourceCriterion:
          requestHost: true