A Practical Guide to Helm/

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Create a Simple Helm Chart

Create a Simple Helm Chart

Learn to define all the necessary templates for a simple Helm chart.

We'll cover the following...

The Chart.yaml file

Once all the template files are removed we can proceed with creating our chart from scratch. Firstly, we’ll define the metadata of our chart in the Chart.yaml file. Here is what we should have by default (for clarity, comments are skipped):

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apiVersion: v2
name: app
description: A Helm chart for Kubernetes
type: application
version: 0.1.0
appVersion: "1.16.0"

In the Chart.yaml file, only apiVersion, name, and version properties are required. All others are optional, but it’s a good practice to add more. Let’s replace the default values with a new one, as follows:

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apiVersion: v2
name: app
description: A Helm chart for any application
type: application
version: 0.1.0
appVersion: "0.0.1"

Next, let’s add more information like who’s the creator, where more information about a chart can be found, and some keywords:

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apiVersion: v2
name: app
description: A Helm chart for any application
type: application
version: 0.1.0
appVersion: "0.0.1"
keywords:
  - app
  - java
  - javascript
  - angular
home: https://github.com/wkrzywiec/k8s-helm-helmfile/tree/master/helm
maintainers:
  - name: John Doe
    url: https://github.com/wkrzywiec

We can now leave it as it is. If we need to know what other options are available we can check the official documentation.

Helm templates

After filling in the necessary data in the Chart.yaml file we can move on to defining Kubernetes resources. In this part, we’ll define two resources: Deployment and Service. Later on, we’ll add more of them.

Our goal is to create the following resources using Helm:

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apiVersion: apps/v1
kind: Deployment
metadata:
  name: kanban-app
  labels:
    app: kanban-app
    group: backend
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kanban-app
  template:
    metadata:
      labels:
        app: kanban-app
        group: backend
    spec:
      containers:
        - name: kanban-app
          image: wkrzywiec/kanban-app:helm-course
          ports:
            - containerPort: 8080
          env:
            - name: DB_SERVER
              value: postgres
            - name: POSTGRES_DB
              value: kanban
            - name: POSTGRES_USER
              value: kanban
            - name: POSTGRES_PASSWORD
              value: kanban
---
apiVersion: v1
kind: Service
metadata:
  name: kanban-app
  labels: 
    group: backend
spec:
  type: ClusterIP
  selector:
    app: kanban-app
  ports:
    - port: 8080
      targetPort: 8080

For the front-end application, both resource definitions would look similar with really small changes.

Since this is a Helm course that focuses primarily on Helm features, most of the time ...