K8s on Daniel Cardozo

Deep Dive into Helm Templates

Fri, 10 May 2024 10:00:00 +0100

Introduction

Helm templates are Kubernetes manifests augmented with Go’s text/template language. They live in the templates/ directory of your chart and are rendered by Helm using values from values.yaml and any user-provided overrides. Understanding them is key to writing maintainable, reusable charts.

Template Basics

A minimal Deployment template:

apiVersion: apps/v1
kind: Deployment
metadata:
 name: {{ .Release.Name }}-app
 labels:
 app: {{ .Chart.Name }}
spec:
 replicas: {{ .Values.replicaCount }}
 selector:
 matchLabels:
 app: {{ .Chart.Name }}
 template:
 metadata:
 labels:
 app: {{ .Chart.Name }}
 spec:
 containers:
 - name: {{ .Chart.Name }}
 image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"

Built-in Objects

Object	Description
`.Release`	Current release info: `.Release.Name`, `.Release.Namespace`
`.Chart`	Contents of `Chart.yaml`: `.Chart.Name`, `.Chart.Version`
`.Values`	Merged values from `values.yaml` and user overrides
`.Files`	Access to non-template files bundled in the chart

Template Functions

Helm bundles Go’s Sprig library with over 60 helper functions:

Helm Tutorial: Managing Kubernetes Applications

Wed, 20 Mar 2024 10:00:00 +0100

What is Helm?

Helm is the package manager for Kubernetes. It lets you define, install, and upgrade complex Kubernetes applications using reusable packages called charts. Think of it as apt or brew, but for Kubernetes.

Key Concepts

Term	Description
Chart	A package containing all Kubernetes resource definitions for an application
Release	A running instance of a chart installed in a cluster
Repository	A place where charts are stored and shared
Values	Configuration parameters that customize a chart at install time

Installation

# macOS
brew install helm

# Linux
curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

Verify the installation:

Getting Started with ArgoCD

Mon, 15 Jan 2024 10:00:00 +0100

What is ArgoCD?

ArgoCD is a declarative, GitOps-based continuous delivery tool for Kubernetes. It automates application deployment by continuously syncing the desired state defined in a Git repository to your Kubernetes cluster — your Git repository becomes the single source of truth.

Prerequisites

A running Kubernetes cluster (or kind for local testing)
kubectl configured to access your cluster
A Git repository containing Kubernetes manifests

Installing ArgoCD

Create the ArgoCD namespace and apply the official installation manifest:

Create backups with Velero

Thu, 30 Jun 2022 19:46:08 +0000

Introduction

Velero is an open source tool to perform backups of your Kubernetes clusters, this also includes your kubernetes volumes! The way Velero works, is by asking the Kubernetes API for the desired manifests you want to backup, that way you do not need a direct access to the etcd Database. This is very useful when you are using managed Kubernetes clusters like AWS, GCP, Digital Ocean etc. As when using managed clusters you do not have direct access to the masters nodes.