InFlightReq¶
Limiting the Number of Simultaneous In-Flight Requests
To proactively prevent services from being overwhelmed with high load, the number of allowed simultaneous in-flight requests can be limited.
Configuration Examples¶
labels:
- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
amount: 10
# Limiting to 10 simultaneous connections
- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
# Limiting to 10 simultaneous connections
http:
middlewares:
test-inflightreq:
inFlightReq:
amount: 10
# Limiting to 10 simultaneous connections
[http.middlewares]
[http.middlewares.test-inflightreq.inFlightReq]
amount = 10
Configuration Options¶
amount
¶
The amount
option defines the maximum amount of allowed simultaneous in-flight request.
The middleware responds with HTTP 429 Too Many Requests
if there are already amount
requests in progress (based on the same sourceCriterion
strategy).
labels:
- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
amount: 10
# Limiting to 10 simultaneous connections
- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
# Limiting to 10 simultaneous connections
http:
middlewares:
test-inflightreq:
inFlightReq:
amount: 10
# Limiting to 10 simultaneous connections
[http.middlewares]
[http.middlewares.test-inflightreq.inFlightReq]
amount = 10
sourceCriterion
¶
The sourceCriterion
option defines what criterion is used to group requests as originating from a common source.
If several strategies are defined at the same time, an error will be raised.
If none are set, the default is to use the requestHost
.
sourceCriterion.ipStrategy
¶
The ipStrategy
option defines three parameters that configures how Traefik determines the client IP: depth
, excludedIPs
and ipv6Subnet
.
As a middleware, InFlightReq happens before the actual proxying to the backend takes place. In addition, the previous network hop only gets appended to X-Forwarded-For
during the last stages of proxying, i.e. after it has already passed through the middleware. Therefore, during InFlightReq, as the previous network hop is not yet present in X-Forwarded-For
, it cannot be used and/or relied upon.
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 inX-Forwarded-For
, then the client IP is empty. depth
is ignored if its value is less than or equal to 0.
If ipStrategy.ipv6Subnet
is provided and the selected IP is IPv6, the IP is transformed into the first IP of the subnet it belongs to.
See ipStrategy.ipv6Subnet for more details.
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-inflightreq.inflightreq.sourcecriterion.ipstrategy.depth=2"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
sourceCriterion:
ipStrategy:
depth: 2
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.depth=2"
http:
middlewares:
test-inflightreq:
inFlightReq:
sourceCriterion:
ipStrategy:
depth: 2
[http.middlewares]
[http.middlewares.test-inflightreq.inflightreq]
[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion.ipStrategy]
depth = 2
ipStrategy.excludedIPs
¶
excludedIPs
configures Traefik to scan the X-Forwarded-For
header and select the first IP not in the list.
If depth
is specified, excludedIPs
is ignored.
Example of ExcludedIPs & X-Forwarded-For
X-Forwarded-For |
excludedIPs |
clientIP |
---|---|---|
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" |
"12.0.0.1,13.0.0.1" |
"11.0.0.1" |
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" |
"15.0.0.1,13.0.0.1" |
"12.0.0.1" |
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" |
"10.0.0.1,13.0.0.1" |
"12.0.0.1" |
"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1" |
"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-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
sourceCriterion:
ipStrategy:
excludedIPs:
- 127.0.0.1/32
- 192.168.1.7
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
http:
middlewares:
test-inflightreq:
inFlightReq:
sourceCriterion:
ipStrategy:
excludedIPs:
- "127.0.0.1/32"
- "192.168.1.7"
[http.middlewares]
[http.middlewares.test-inflightreq.inflightreq]
[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion.ipStrategy]
excludedIPs = ["127.0.0.1/32", "192.168.1.7"]
ipStrategy.ipv6Subnet
¶
This strategy applies to Depth
and RemoteAddr
strategy only.
If ipv6Subnet
is provided and the selected IP is IPv6, the IP is transformed into the first IP of the subnet it belongs to.
This is useful for grouping IPv6 addresses into subnets to prevent bypassing this middleware by obtaining a new IPv6.
ipv6Subnet
is ignored if its value is outside of 0-128 interval
Example of ipv6Subnet
If ipv6Subnet
is provided, the IP is transformed in the following way.
IP |
ipv6Subnet |
clientIP |
---|---|---|
"::abcd:1111:2222:3333" |
64 |
"::0:0:0:0" |
"::abcd:1111:2222:3333" |
80 |
"::abcd:0:0:0:0" |
"::abcd:1111:2222:3333" |
96 |
"::abcd:1111:0:0:0" |
labels:
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.ipv6Subnet=64"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
sourceCriterion:
ipStrategy:
ipv6Subnet: 64
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.ipv6Subnet=64"
http:
middlewares:
test-inflightreq:
inFlightReq:
sourceCriterion:
ipStrategy:
ipv6Subnet: 64
[http.middlewares]
[http.middlewares.test-inflightreq.inflightreq]
[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion.ipStrategy]
ipv6Subnet = 64
sourceCriterion.requestHeaderName
¶
Name of the header used to group incoming requests.
labels:
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername=username"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
sourceCriterion:
requestHeaderName: username
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername=username"
http:
middlewares:
test-inflightreq:
inFlightReq:
sourceCriterion:
requestHeaderName: username
[http.middlewares]
[http.middlewares.test-inflightreq.inflightreq]
[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion]
requestHeaderName = "username"
sourceCriterion.requestHost
¶
Whether to consider the request host as the source.
labels:
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
name: test-inflightreq
spec:
inFlightReq:
sourceCriterion:
requestHost: true
- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
http:
middlewares:
test-inflightreq:
inFlightReq:
sourceCriterion:
requestHost: true
[http.middlewares]
[http.middlewares.test-inflightreq.inflightreq]
[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion]
requestHost = true