Routing and managing traffic by using the Knative CLI

You can use the following kn CLI command to split traffic between revisions:

$ kn service update –traffic =

For example, to split traffic for a Service named example, by sending 80% of traffic to the Revision green and 20% of traffic to the Revision blue, you could run the following command:

$ kn service update example-service –traffic green=80 –traffic blue=20

It is also possible to add tags to Revisions and then split traffic according to the tags you have set:

$ kn service update example –tag revision-0001=green –tag @latest=blue

The @latest tag means that blue resolves to the latest Revision of the Service. The following example sends 80% of traffic to the latest Revision and 20% to a Revision named v1.

$ kn service update example-service –traffic @latest=80 –traffic v1=20

The following example shows a traffic spec where 100% of traffic is routed to the latestRevision of the Service. Under status you can see the name of the latest Revision that latestRevision was resolved to:

	apiVersion: serving.knative.dev/v1
	kind: Service
	metadata:
	name: hello
	spec:
	template:
	spec:
	containers:
	- image: gcr.io/knative-samples/helloworld-go
	ports:
	- containerPort: 8080
	env:
	- name: TARGET
	value: "Knative-2"
	traffic:
	- latestRevision: true
	percent: 100

view raw Knative-Service-traffic-1yaml hosted with by GitHub

The following example shows a traffic spec where 100% of traffic is routed to the current Revision, and the name of that Revision is specified as example-service-1. The latest ready Revision is kept available, even though no traffic is being routed to it:

	apiVersion: serving.knative.dev/v1
	kind: Service
	metadata:
	name: hello
	spec:
	template:
	spec:
	containers:
	- image: gcr.io/knative-samples/helloworld-go
	ports:
	- containerPort: 8080
	env:
	- name: TARGET
	value: "Knative-2"
	traffic:
	- tag: current
	revisionName: example-service-1
	percent: 100
	- tag: latest
	latestRevision: true
	percent: 0

view raw Knative-Service-traffic-2.yaml hosted with by GitHub

The following example shows how the list of Revisions in the traffic spec can be extended so that traffic is split between multiple Revisions. This example sends 50% of traffic to the current Revision, example-service-1, and 50% of traffic to the candidate Revision, example-service-2:

	apiVersion: serving.knative.dev/v1
	kind: Service
	metadata:
	name: hello
	spec:
	template:
	spec:
	containers:
	- image: gcr.io/knative-samples/helloworld-go
	ports:
	- containerPort: 8080
	env:
	- name: TARGET
	value: "Knative-2"
	traffic:
	- tag: current
	revisionName: example-service-1
	percent: 50
	- tag: candidate
	revisionName: example-service-2
	percent: 50
	- tag: latest
	latestRevision: true
	percent: 0

view raw Knative-Service-Traffic-3.yaml hosted with by GitHub

Rajesh Kumar

I’m a DevOps/SRE/DevSecOps/Cloud Expert passionate about sharing knowledge and experiences. I am working at Cotocus. I blog tech insights at DevOps School, travel stories at Holiday Landmark, stock market tips at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at I reviewed , and SEO strategies at Wizbrand. 

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