Helm_Lab_05 | Functions

Working-with-Helm

Helm Lab 05

Purpose

The Purpose of this lab is to give the understanding of existing functions in helm

Till now we have used the templating feature of the helm, but now we would like to know how we can have more programmatic control over the helm chart.

01

Let's start by adding if and else statement for liveness and readiness probe. In which the liveness and readiness probe will only get applied if it is enabled

• Update the gowebapp/templates/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: goweb-app
  labels:
    app.kubernetes.io/name: app
    app.kubernetes.io/instance: goweb-app
    app.kubernetes.io/version: "1.16.0"
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: app
      app.kubernetes.io/instance: goweb-app
  template:
    metadata:
      labels:
        app.kubernetes.io/name: app
        app.kubernetes.io/instance: goweb-app
    spec:
      containers:
        - name: {{ .Values.containers.name }}
          image: "{{ .Values.containers.image }}:{{ .Values.containers.tag }}"
          imagePullPolicy: IfNotPresent
          ports:
          - name: http
            containerPort: 8080
            protocol: TCP
          env:
          - name: DB_URL
            value: goweb-app-mysql
          - name: DB_PORT
            value: "3306"
          - name: DB_USER
            value: "root"
          - name: DB_PASSWORD
            value: password
          - name: REDIS_HOST
            value: "goweb-app-redis-headless"
          - name: REDIS_PORT
            value: "6379"
{{- if .Values.containers.livenessProbe.enabled }}
          livenessProbe:
            tcpSocket:
              port: {{ int .Values.containers.livenessProbe.tcpSocket.port }}
            initialDelaySeconds: 5
            periodSeconds: 5
{{- end }}
{{- if .Values.containers.readinessProbe.enabled }}
          readinessProbe:
            tcpSocket:
              port: {{ int .Values.containers.readinessProbe.tcpSocket.port }}
            initialDelaySeconds: 5
            periodSeconds: 5
{{- end }}

• Update the gowebapp/values.yaml file

mysql:
  mysqlDatabase: employeedb
  mysqlRootPassword: password
  persistence:
    enabled: false

redis:
  usePassword: false
  cluster:
    enabled: false
  master:
    persistence:
      enabled: false

containers:
  name: gowebapp
  image: opstreedevops/ot-go-webapp
  tag: "v1"
  livenessProbe:
    enabled: true
    tcpSocket:
      port: 8080
  readinessProbe:
    enabled: true
    tcpSocket:
      port: 8080

02

Let's add with block to change scope of helm

• Update the gowebapp/templates/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: goweb-app
  labels:
    app.kubernetes.io/name: app
    app.kubernetes.io/instance: goweb-app
    app.kubernetes.io/version: "1.16.0"
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: app
      app.kubernetes.io/instance: goweb-app
  template:
    metadata:
      labels:
        app.kubernetes.io/name: app
        app.kubernetes.io/instance: goweb-app
    spec:
      containers:
        - name: {{ .Values.containers.name }}
          image: "{{ .Values.containers.image }}:{{ .Values.containers.tag }}"
          imagePullPolicy: IfNotPresent
          ports:
          - name: http
            containerPort: 8080
            protocol: TCP
          env:
          - name: DB_URL
            value: goweb-app-mysql
          - name: DB_PORT
            value: "3306"
          - name: DB_USER
            value: "root"
          - name: DB_PASSWORD
            value: password
          - name: REDIS_HOST
            value: "goweb-app-redis-headless"
          - name: REDIS_PORT
            value: "6379"
{{- if .Values.containers.livenessProbe }}
      {{- with .Values.containers.livenessProbe }}
        {{- toYaml . | nindent 10 }}
      {{- end }}
{{- end }}
{{- if .Values.containers.readinessProbe }}
      {{- with .Values.containers.readinessProbe }}
        {{- toYaml . | nindent 10 }}
      {{- end }}
{{- end }}

• Update the gowebapp/values.yaml file

mysql:
  mysqlDatabase: employeedb
  mysqlRootPassword: password
  persistence:
    enabled: false

redis:
  usePassword: false
  cluster:
    enabled: false
  master:
    persistence:
      enabled: false

containers:
  name: gowebapp
  image: opstreedevops/ot-go-webapp
  tag: "v1"
  livenessProbe:
    tcpSocket:
      port: 8080
    initialDelaySeconds: 5
    periodSeconds: 5
  readinessProbe:
    tcpSocket:
      port: 8080
    initialDelaySeconds: 5
    periodSeconds: 5