---
tags: k8s-fundamentals
---
# Deploying application to K8S
## Goals
* Create a sample cowsay web app
* Using buildpacks to build the app image and push to docker hub
* Create a kind cluster where the app is deployed to
* Deploy Contour as the Ingress controller
## Create a golang simple web app
https://github.com/danniel1205/sample-cowsay-web-app
## Build the application image by using buildpack
### Install buildpack on Mac OS
https://buildpacks.io/docs/app-journey/

brew tap buildpack/tap
brew install pack

### Build the app image

cd $GOPATH/src
git clone https://github.com/danniel1205/sample-cowsay-web-app.git
pack build -B --builder gcr.io/paketo-buildpacks/builder:tiny danielguo/cowsay-web-app:latest --publish

Builder: https://github.com/paketo-buildpacks/builder
## Deploy the application to K8S
### Start a kind cluster

kind create cluster --image kindest/node:v1.18.0 --config ./kind.yaml

# kind.yaml

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: InitConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "ingress-ready=true"
        authorization-mode: "AlwaysAllow"
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    protocol: TCP
  - containerPort: 443
    hostPort: 443
    protocol: TCP
- role: worker
- role: worker
- role: worker

### Create a Deployment/Service
* kubectl apply -f the following two yaml files

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: cowsay
  name: cowsay
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cowsay
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: cowsay
    spec:
      containers:
      - image: danielguo/cowsay-web-app
        imagePullPolicy: IfNotPresent
        name: cowsay-web-app
        resources: {}
status: {}

apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: cowsay
  name: cowsay
spec:
  ports:
  - port: 1323
  selector:
    app: cowsay
status:
  loadBalancer: {}

* `kubectl port-forward service/cowsay 8081:1323`
* Access to the web app on borwser: `localhost:8081`
## (Optional) Deploy Contour
The reason of deploying Contour is to get rid of doing port-forwarding
* Install Contour

kubectl apply -f https://projectcontour.io/quickstart/contour.yaml

* Apply kind specific patches to forward the hostPorts to the ingress controller, set taint tolerations and schedule it to the custom labelled node.

kubectl patch daemonsets -n projectcontour envoy -p '{"spec":{"template":{"spec":{"nodeSelector":{"ingress-ready":"true"},"tolerations":[{"key":"node-role.kubernetes.io/master","operator":"Equal","effect":"NoSchedule"}]}}}}'

* Create HttpProxy

apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: cowsay
spec:
  virtualhost:
    fqdn: local.daniel.io
  routes:
    - services:
      - name: cowsay
        port: 1323
      conditions:
        - prefix: /

**Note:**
* You might want to add `127.0.0.1 local.daniel.io` to your `/etc/hosts` to make the fqnd work

Now you should be able to access the cowsay web service by `curl http://local.daniel.io/`

## (Optional) Create TLS for HttpProxy
* Create self signed TLS cert

openssl req -x509 -newkey rsa:4096 -sha256 -nodes -keyout tls.key -out tls.crt -subj "/CN=local.daniel.io" -days 5

**Note:** The CN should match the one you specified for your fqdn
* Create k8s secret

kubectl create secret tls local-daniel-io-tls --cert=tls.crt --key=tls.key

* Add the secret in your HttpProxy spec
https://github.com/projectcontour/contour/blob/master/apis/projectcontour/v1/httpproxy.go

apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: cowsay
spec:
  virtualhost:
    fqdn: local.daniel.io
    tls:
      secretName: local-daniel-io-tls
  routes:
    - services:
      - name: cowsay-blue
        port: 1323
      conditions:
        - prefix: /

kubectl apply above changes. Then you should be able to access `https://local.daniel.io`

## References
https://github.com/bryanl/websay
https://echo.labstack.com/guide
https://github.com/Code-Hex/Neo-cowsay
https://paketo.io/docs/getting-started/build-your-application/
https://kind.sigs.k8s.io/docs/user/ingress/
https://projectcontour.io/docs/v1.4.0/httpproxy/