mirror of https://github.com/knative/docs.git
48 lines
2.1 KiB
Markdown
48 lines
2.1 KiB
Markdown
## Blue/Green deploy
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The Knative `service` resource creates additional resources "route, configuration and revision" to manage the lifecycle of the application.
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- revision: just like a git revision, any change to the Service's `spec.template` results in a new revision
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- route: control traffic to several revisions
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You can list those resources by running `kubectl get ksvc,configuration,route,revision` or by using the `kn` cli
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We will now update the service to change the `TARGET` env variable to `green`.
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But, before we do that, let us update the revision name to "hello-v1", so that we can direct traffic to it.
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```
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kn service update demo --revision-name="demo-v1"```{{execute T1}}
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Now, let's update the env variable to `green`, but let's do it as a dark launch i.e. zero traffic will go to this new revision:
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```
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kn service update demo --env TARGET=green --revision-name="demo-v2" --traffic demo-v1=100,demo-v2=0
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```{{execute T1}}
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This will result in a new `revision` being created. Verify this by running `kn revision list`{{execute T1}}.
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All these revisions are capable of serving requests. Let's tag the `green` revision, so as to get a custom hostname to be able to access the revision.
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```
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kn service update demo --tag demo-v2=v2
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```{{execute T1}}
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You can now test the `green` revision like so: (This hostname can be listed with `kn route describe demo` command).
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```
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curl http://$MINIKUBE_IP:$INGRESS_PORT/ -H 'Host: v2-demo.default.example.com'
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```{{execute T1}}
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We now need to split our traffic between the two revisions.
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```
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kn service update demo --traffic demo-v1=50,@latest=50
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```{{execute T1}}
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Then proceed by issuing the curl command multiple times to see that the traffic is split between the two revisions.
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```
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curl http://$MINIKUBE_IP:$INGRESS_PORT/ -H 'Host: demo.default.example.com'
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```{{execute T1}}
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We can now make all traffic go to the `green` revision:
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```
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kn service update demo --traffic @latest=100
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```{{execute T1}}
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Then proceed by issuing the curl command multiple times to see that all traffic is routed to `green` revision.
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```
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curl http://$MINIKUBE_IP:$INGRESS_PORT/ -H 'Host: demo.default.example.com'
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```{{execute T1}}
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