This project contains an Angular app + a Knative YAML that can be used to deploy services on Kubernetes without dealing with its complexities.
Instead of using a myriad of different YAML files that describe various low-level aspects like Deyploment, Ingress, Service and so on, we use a single YAML file and let Knative do the heavy lifting for us.
You will need a running Kubernetes instance like minikube, kind or Kubernetes on Docker Desktop.
After you have setup your preferred K8s it's time to install Knative. Knative itself comprises of two basic blocks: Eventing and Serving. In the past there was a third one, Building, but it got extracted into a project of its own: Tekton.
The easiest way to install Knative is via Knative's quickstart plugin.
Test your Knative installation by entering these commands:
$ kn version
Version: v1.3.1
Build Date: 2022-03-11 18:43:10
Git Revision: a591c0c0
Supported APIs:
* Serving
- serving.knative.dev/v1 (knative-serving v1.3.0)
* Eventing
- sources.knative.dev/v1 (knative-eventing v1.3.0)
- eventing.knative.dev/v1 (knative-eventing v1.3.0)$ kubectl get pods -n knative-serving
NAME READY STATUS RESTARTS AGE
activator-855fbdfd77-5jhn5 1/1 Running 0 7h30m
autoscaler-85748d9cf4-p654d 1/1 Running 0 7h30m
controller-798994c5bd-8vsgk 1/1 Running 0 7h30m
default-domain-nl86s 0/1 Completed 0 7h29m
domain-mapping-59fdc67c94-qnxgt 1/1 Running 0 7h30m
domainmapping-webhook-6df595d448-5k8vl 1/1 Running 0 7h30m
net-kourier-controller-74dc74797-bp65n 1/1 Running 0 7h29m
webhook-69fdbbf67d-wxwsg 1/1 Running 0 7h30m$ kubectl get pods -n knative-eventing
NAME READY STATUS RESTARTS AGE
eventing-controller-59475d565c-74qrt 1/1 Running 0 7h29m
eventing-webhook-74cbb75cb-f4hc2 1/1 Running 0 7h29m
imc-controller-84c7f75c67-7jbg8 1/1 Running 0 7h29m
imc-dispatcher-7786967556-48tcx 1/1 Running 0 7h29m
mt-broker-controller-65bb965bf9-hkn7q 1/1 Running 0 7h29m
mt-broker-filter-8496c9765-q6rg2 1/1 Running 0 7h29m
mt-broker-ingress-67959dc68f-8sf7c 1/1 Running 0 7h29mAll that needs to be done is:
$ kubectl apply -f ng-demo.yaml
The YAML file itself contains the CRD Service which is defined by Knative.
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: ng-demo
spec:
template:
metadata:
# This is the name of the revision. It must follow the convention {service-name}-{revision-name}
name: ng-demo-v2
annotations:
autoscaling.knative.dev/target: "2"
spec:
containers:
- image: brakmic/ng-demo:0.2
ports:
- containerPort: 80To check the deployment status of the app:
$ kn services list
NAME URL LATEST AGE CONDITIONS READY REASON
ng-demo http://ng-demo.default.127.0.0.1.sslip.io ng-demo-v2 31m 3 OK / 3 TrueKnative is not only defining all the basic stuff like Deyploment, Ingress, Service, but also setting up a local DNS.
To get the K8s deployment:
$ kubectl get deployments -n default
NAME READY UP-TO-DATE AVAILABLE AGE
ng-demo-v1-deployment 0/0 0 0 42m
ng-demo-v2-deployment 0/0 0 0 29mAs shown above, we can have many revisions that can also run in parallel and get assigned different ports. In your case you'll see only the second deployment as this is the only one available by default when running from this repo.
However, it's very easy to create a new revision. Just change the name in the metadata of the YAML file and do a kubectl apply again.
With Knative we can also run multiple revisions art the same time and also split the traffic between them.
traffic:
- tag: current
revisionName: ng-demo-v2
percent: 50
- tag: upcoming
revisionName: ng-demo-v3
percent: 50Take the other YAML file called ng-demo-with-revisions and apply it with kubectl.
Then execute this to get an overview of running services and routes:
$ watch -n 1 kubectl get pod,ksvc,configuration,revision,route
You should see two pods and deployments in a list similar to this:
Every 1.0s: kubectl get pod,ksvc,configuration,revision,route BRAK9000
NAME READY STATUS RESTARTS AGE
pod/ng-demo-v2-deployment-59c4b8b784-zjhxp 2/2 Running 0 58s
pod/ng-demo-v3-deployment-f4648c7cd-2spdl 2/2 Running 0 24s0
NAME URL LATESTCREATED LATESTREADY READY REASON
service.serving.knative.dev/ng-demo http://ng-demo.default.127.0.0.1.sslip.io ng-demo-v3 ng-demo-v3 True
NAME LATESTCREATED LATESTREADY READY REASON
configuration.serving.knative.dev/ng-demo ng-demo-v3 ng-demo-v3 True
NAME CONFIG NAME K8S SERVICE NAME GENERATION READY REASON ACTUAL REPLICAS DESIRED REPLICAS
revision.serving.knative.dev/ng-demo-v1 ng-demo 1 False ProgressDeadlineExceeded 0
revision.serving.knative.dev/ng-demo-v2 ng-demo 2 True 1 1
revision.serving.knative.dev/ng-demo-v3 ng-demo 3 True 1 1
NAME URL READY REASON
route.serving.knative.dev/ng-demo http://ng-demo.default.127.0.0.1.sslip.io True