Traffic Route
New to Kuma? Don’t use this, check the MeshHTTPRoute
or MeshTCPRoute
policy policies instead.
Traffic Route is an outbound policy. Dataplanes whose configuration is modified are in the sources
matcher.
This policy lets you configure routing rules for the traffic in the mesh. It supports weighted routing and can be used to implement versioning across services or to support deployment strategies such as blue/green or canary.
Note the following:
- The configuration must specify the data plane proxies for the routing rules.
- The
spec.destinations
field supports onlykuma.io/service
. - All available tags are supported for
spec.conf
. - This is an outbound connection policy. Make sure that your data plane proxy configuration includes the appropriate tags.
Kuma also supports locality aware load balancing.
Default TrafficRoute
The control plane creates a default TrafficRoute
every time a new Mesh
is created. The default TrafficRoute
enables the traffic between all the services in the mesh.
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: route-all-default
spec:
sources:
- match:
kuma.io/service: '*'
destinations:
- match:
kuma.io/service: '*'
conf:
loadBalancer:
roundRobin: {}
destination:
kuma.io/service: '*'
Usage
Here is a full example of TrafficRoute
policy
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: full-example
spec:
sources:
- match:
kuma.io/service: backend_default_svc_80
destinations:
- match:
kuma.io/service: redis_default_svc_6379
conf:
http:
- match:
method: # one of either "prefix", "exact" or "regex" is allowed
exact: GET
regex: "^POST|PUT$"
path: # one of either "prefix", "exact" or "regex" is allowed
prefix: /users
exact: /users/user-1
regex: "^users$"
headers:
some-header: # one of either "prefix", "exact" or "regex" will be allowed
exact: some-value
prefix: some-
regex: "^users$"
modify: # optional section
path: # one of "rewritePrefix" or "regex" is allowed
rewritePrefix: /not-users # rewrites previously matched prefix
regex: # (example to change the path from "/service/foo/v1/api" to "/v1/api/instance/foo")
pattern: "^/service/([^/]+)(/.*)$"
substitution: '\2/instance/\1'
host: # one of "value" or "fromPath" is allowed
value: "XYZ"
fromPath: # (example to extract "envoyproxy.io" host header from "/envoyproxy.io/some/path" path)
pattern: "^/(.+)/.+$"
substitution: '\1'
requestHeaders:
add:
- name: x-custom-header
value: xyz
append: true # if true then if there is x-custom-header already, it will append xyz to the value
remove:
- name: x-something
responseHeaders:
add:
- name: x-custom-header
value: xyz
append: true
remove:
- name: x-something
destination: # one of "destination", "split" is allowed
kuma.io/service: redis_default_svc_6379
split:
- weight: 100
destination:
kuma.io/service: redis_default_svc_6379
destination: # one of "destination", "split" is allowed
kuma.io/service: redis_default_svc_6379
split:
- weight: 100
destination:
kuma.io/service: redis_default_svc_6379
loadBalancer: # one of "roundRobin", "leastRequest", "ringHash", "random", "maglev" is allowed
roundRobin: {}
leastRequest:
choiceCount: 8
ringHash:
hashFunction: "MURMUR_HASH_2"
minRingSize: 64
maxRingSize: 1024
random: {}
maglev: {}
Kuma utilizes positive weights in the TrafficRoute
policy and not percentages, therefore Kuma does not check if the total adds up to 100. If we want to stop sending traffic to a destination service we change the weight
for that service to 0.
L4 Traffic Split
We can use TrafficRoute
to split a TCP traffic between services with different tags implementing A/B testing or canary deployments.
Here is an example of a TrafficRoute
that splits the traffic over the two different versions of the application.
90% of the connections from backend_default_svc_80
service will be initiated to redis_default_svc_6379
with tag version: 1.0
and 10% of the connections will be initiated to version: 2.0
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: split-traffic
spec:
sources:
- match:
kuma.io/service: backend_default_svc_80
destinations:
- match:
kuma.io/service: redis_default_svc_6379
conf:
split:
- weight: 90
destination:
kuma.io/service: redis_default_svc_6379
version: '1.0'
- weight: 10
destination:
kuma.io/service: redis_default_svc_6379
version: '2.0'
L4 Traffic Rerouting
We can use TrafficRoute
to fully reroute a TCP traffic to different version of a service or even completely different service.
Here is an example of a TrafficRoute
that redirects the traffic to another-redis_default_svc_6379
when backend_default_svc_80
is trying to consume redis_default_svc_6379
.
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: reroute-traffic
spec:
sources:
- match:
kuma.io/service: backend_default_svc_80
destinations:
- match:
kuma.io/service: redis_default_svc_6379
conf:
destination:
kuma.io/service: another-redis_default_svc_6379
L7 Traffic Split
We can use TrafficRoute
to split an HTTP traffic between services with different tags implementing A/B testing or canary deployments.
Here is an example of a TrafficRoute
that splits the traffic from frontend_default_svc_80
to backend_default_svc_80
between versions,
but only on endpoints starting with /api
. All other endpoints will go to version: 1.0
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: api-split
spec:
sources:
- match:
kuma.io/service: frontend_default_svc_80
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
- match:
path:
prefix: "/api"
split:
- weight: 90
destination:
kuma.io/service: backend_default_svc_80
version: '1.0'
- weight: 10
destination:
kuma.io/service: backend_default_svc_80
version: '2.0'
destination: # default rule is applied when endpoint does not match any rules in http section
kuma.io/service: backend_default_svc_80
version: '1.0'
In order to use L7 Traffic Split, we need to mark the destination service with kuma.io/protocol: http
.
L7 Traffic Modification
We can use TrafficRoute
to modify outgoing requests, by setting new path or changing request and response headers.
Here is an example of a TrafficRoute
that adds x-custom-header
with value xyz
when frontend_default_svc_80
tries to consume backend_default_svc_80
.
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: add-header
spec:
sources:
- match:
kuma.io/service: frontend_default_svc_80
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
- match:
path:
prefix: "/"
modify:
requestHeader:
add:
- name: x-custom-header
value: xyz
destination:
kuma.io/service: backend_default_svc_80
destination:
kuma.io/service: backend_default_svc_80
In order to use L7 Traffic Modification, we need to mark the destination service with kuma.io/protocol: http
.
L7 Traffic Rerouting
We can use TrafficRoute
to modify outgoing requests, by setting new path or changing request and response headers.
Here is an example of a TrafficRoute
that redirect traffic to offers_default_svc_80
when frontend_default_svc_80
is trying to consume backend_default_svc_80
on /offers
endpoint.
apiVersion: kuma.io/v1alpha1
kind: TrafficRoute
mesh: default
metadata:
name: http-reroute
spec:
sources:
- match:
kuma.io/service: frontend_default_svc_80
destinations:
- match:
kuma.io/service: backend_default_svc_80
conf:
http:
- match:
path:
prefix: "/offers"
destination:
kuma.io/service: offers_default_svc_80
destination:
kuma.io/service: backend_default_svc_80
In order to use L7 Traffic Rerouting, we need to mark the destination service with kuma.io/protocol: http
.
Load balancer types
There are different load balancing algorithms that can be used to determine how traffic is routed to the destinations. By default TrafficRoute
uses the roundRobin
load balancer, but more options are available:
-
roundRobin
is a simple algorithm in which each available upstream host is selected in round robin order.Example:
loadBalancer: roundRobin: {}
-
leastRequest
uses different algorithms depending on whether the hosts have the same or different weights. It has a single configuration fieldchoiceCount
, which denotes the number of random healthy hosts from which the host with the fewer active requests will be chosen.Example:
loadBalancer: leastRequest: choiceCount: 8
ringHash
implements consistent hashing to the upstream hosts. It has the following fields:hashFunction
the hash function used to hash the hosts onto the ketama ring. Can beXX_HASH
orMURMUR_HASH_2
.minRingSize
minimum hash ring size.maxRingSize
maximum hash ring size.
Example:
loadBalancer: ringHash: hashFunction: "MURMUR_HASH_2" minRingSize: 64 maxRingSize: 1024
-
random
selects a random available host.Example:
loadBalancer: random: {}
-
maglev
implements consistent hashing to upstream hostsExample:
loadBalancer: maglev: {}