Overview Helm is the package manager for Kubernetes, like apt, yum, or Homebrew for traditional operating systems. It simplifies the deployment and management of applications on Kubernetes clusters by packaging all necessary components into a single, manageable unit. Why Helm? : Helm packages, known as charts, bundle together all the Kubernetes manifests (like deployments, services, etc.) needed to deploy an application, making the deployment process straightforward and repeatable. Simplifies Kubernetes Deployments : Helm charts can include other charts, allowing complex applications to manage their dependencies effectively. Manages Dependencies : Helm tracks versions of deployments, enabling rollbacks to previous states if needed. Version Control for Deployments What Is It Made of? : A Helm chart is a bundle containing all information necessary to create an instance of a Kubernetes application. It includes resource definitions and configuration files. Chart : The configuration contains customizable parameters that merge with a chart to create a release. These parameters allow the same chart to be used in different environments or configurations. Config : A release is an instance of a chart running in a Kubernetes cluster combined with a specific configuration. Release Helm Architecture Diagram : Helm Client : Local chart development and managing repositories. Chart Development : Manages releases/repos and requests chart installation or release upgrade/uninstallation through Helm Library. Release Management : Helm Library : Handles combining charts and configurations to create releases and installing/upgrading/uninstalling charts. Chart Management : Interfaces with the Kubernetes API server. Interacts with Kubernetes Creating a Chart Creating a Helm chart involves setting up a predefined directory structure with at least two files: for metadata about the chart and for default configuration values. Chart.yaml values.yaml : A basic chart directory will have the following layout: Structure : Contains metadata about the chart such as name, version, and description. Chart.yaml : Specifies default configuration values for the chart. values.yaml : This directory contains template files that generate Kubernetes manifest files based on the values provided. templates/ : Helm uses a templating engine to substitute values in the chart templates, creating Kubernetes manifests tailored to specific deployments. This allows for dynamic adjustment of resources, labels, and configurations without altering the original chart files. Templating Practice : Scenario A startup, "DevOps Solutions" adopts Helm to streamline their Kubernetes deployments. You're a consultant tasked with creating a basic Helm Chart for . It should be customizable for different environments using values. n8n Clone the repo. git clone https://github.com/perplexedyawdie/helm-learn.git Change directory to creating-charts cd helm-learn/creating-charts Spin up the environment using docker-compose. docker compose up -d --build SSH into the container. ubuntu ssh -o StrictHostKeyChecking=no -o NoHostAuthenticationForLocalhost=yes root@localhost -p 2222 # password: test123 Generate a chart directory along with sample files. helm create my-n8n View the structure of the generated directory. tree . # Output should look similar to this #`-- my-n8n # |-- Chart.yaml # |-- charts # |-- templates # | |-- NOTES.txt # | |-- _helpers.tpl # | |-- deployment.yaml # | |-- hpa.yaml # | |-- ingress.yaml # | |-- service.yaml # | |-- serviceaccount.yaml # | `-- tests # | `-- test-connection.yaml # `-- values.yaml We'll only be using , , and so we can remove the rest since we'll be adding our own manifest files. Chart.yaml values.yaml my-n8n/templates/NOTES.txt my-n8n/templates/_helpers.tpl rm -rf my-n8n/templates/*.yaml my-n8n/templates/tests Update the appVersion in Chart.yaml to "1.27.2" & clear the contents of my-n8n/templates/NOTES.txt file then update with the following. nano my-n8n/Chart.yaml # appVersion: "1.27.2" nano my-n8n/templates/NOTES.txt # Welcome to n8n. # Wait a few minutes until the status changes to RUNNING. # After it is ready, access it from: http://localhost:2223 Update the file with the following data. values.yaml # Default values for my-n8n. # This is a YAML-formatted file. # Declare variables to be passed into your templates. replicaCount: 1 image: repository: n8nio/n8n pullPolicy: IfNotPresent # Overrides the image tag whose default is the chart appVersion. tag: "1.27.2" containerPorts: - name: http port: 5678 service: type: NodePort port: 30200 livenessProbe: httpGet: path: / port: http readinessProbe: httpGet: path: / port: http autoscaling: enabled: false minReplicas: 1 maxReplicas: 100 targetCPUUtilizationPercentage: 80 # targetMemoryUtilizationPercentage: 80 # Additional volumes on the output Deployment definition. volumes: - name: n8n-data persistence: claimName: n8n-data # Additional volumeMounts on the output Deployment definition. volumeMounts: - name: n8n-data mountPath: "/home/node/.n8n" Create the , and, files inside the folder. deployment.yaml service.yaml pvc.yaml my-n8n/templates # my-n8n/templates/pvc.yaml apiVersion: v1 kind: PersistentVolumeClaim metadata: name: n8n-data spec: accessModes: - ReadWriteOnce resources: requests: storage: 1Gi # Adjust the size as per your requirement # my-n8n/templates/deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: name: n8n spec: replicas: 1 selector: matchLabels: app: n8n template: metadata: labels: app: n8n spec: containers: - name: n8n image: n8nio/n8n ports: - name: http - containerPort: 5678 volumeMounts: - name: n8n-data mountPath: /home/node/.n8n volumes: - name: n8n-data persistentVolumeClaim: claimName: n8n-data # my-n8n/templates/service.yaml apiVersion: v1 kind: Service metadata: name: n8n spec: type: NodePort ports: - port: 5678 targetPort: 30200 protocol: TCP selector: app: n8n Now, let's parameterize these using the go-template language to convert them to templates. Helm will fetch the appropriate values from the file to generate the manifest that will be deployed on K8S. values.yaml # my-n8n/templates/pvc.yaml apiVersion: v1 kind: PersistentVolumeClaim metadata: name: {{ .Values.persistence.claimName }} spec: accessModes: - ReadWriteOnce resources: requests: storage: 1Gi # Adjust the size as per your requirement # my-n8n/templates/deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: name: {{ printf "%s-%s" .Release.Name .Chart.Name }} spec: replicas: 1 selector: matchLabels: app: n8n template: metadata: labels: app: n8n spec: containers: - name: n8n image: {{ printf "%s:%s" .Values.image.repository .Values.image.tag }} ports: {{- range .Values.containerPorts }} - name: {{ .name }} containerPort: {{ .port }} {{- end }} volumeMounts: {{- range .Values.volumeMounts }} - name: {{ .name }} mountPath: {{ .mountPath }} {{- end }} volumes: {{- range .Values.volumes }} - name: {{ .name }} persistentVolumeClaim: claimName: {{ $.Values.persistence.claimName }} {{- end }} # my-n8n/templates/service.yaml apiVersion: v1 kind: Service metadata: name: {{ printf "%s-%s" .Release.Name .Chart.Name }} spec: type: {{ .Values.service.type }} ports: - port: 5678 targetPort: 5678 nodePort: {{ .Values.service.port }} protocol: TCP selector: app: n8n Ensure that you're in the directory that contains the chart then run the linter. my-n8n helm lint my-n8n Install the chart. helm install my-n8n ./my-n8n Wait until the deployment is complete, you can continually check using the following command. kubectl get all After the status has changed to running, you should be able to access it in your browser from: http://localhost:2223 Recap Great effort! You just learned how to create and configure a Helm chart and then deploy it to a Kubernetes cluster!
