Default App Helm Chart

This Helm Chart is designed to deploy applications in Kubernetes, providing a standardized structure and flexible configuration options. It supports various deployment scenarios including standalone deployments, external secrets management, and persistent storage configurations.

Installation

Ensure that Helm is installed and that you have access to a Kubernetes cluster before proceeding with the installation.

Add the Helm repository and update it:

helm repo add simple-chart https://atlet99.github.io/simple-helm-template
helm repo update

To install the application, run:

helm install my-app simple-chart/default-app -f values.yaml

To install the application with a specific version:

helm upgrade --install my-app simple-chart/default-app -f values.yaml --version 0.3.4 --atomic

Checking

Check available versions of the chart:

helm search repo simple-chart/default-app --versions

Verify the chart archive download:

helm pull simple-chart/default-app --version 0.3.4

Upgrading

To upgrade the application with new parameters:

helm upgrade my-app simple-chart/default-app -f values.yaml

Uninstallation

To remove the release:

helm uninstall my-app

Configuration

This Chart supports various parameters that can be defined in values.yaml. Below are the key configurations:

# Application version
appVersion: "1.0.0"

# Number of replicas
replicaCount: 1

# Container image configuration
image:
  repository: {}
  pullPolicy: IfNotPresent
  tag: ""

# Image pull secrets
imagePullSecrets: []

# Name overrides
nameOverride: ""
fullnameOverride: ""

# Namespace override
namespaceOverride: ""

# Service account configuration
serviceAccount:
  create: false
  automount: false
  name: ""

# Pod configuration
podAnnotations: {}
podLabels: {}

# Security context configuration
containerSecurityContext: {}
podSecurityContext: {}

# Service configuration
service:
  type: ClusterIP
  ports:
    - name: http
      port: 80
      targetPort: http
      protocol: TCP
      nodePort: null

# Ingress configuration
ingress:
  enabled: false
  className: ""
  annotations: {}
  hosts:
    - host: chart-example.local
      paths:
        - path: /
          pathType: ImplementationSpecific
  tls: []

# Resource limits and requests
resources:
  limits:
    cpu: 100m
    memory: 128Mi
  requests:
    cpu: 100m
    memory: 128Mi

# Autoscaling configuration
autoscaling:
  enabled: false
  minReplicas: 1
  maxReplicas: 100
  targetCPUUtilizationPercentage: 80
  targetMemoryUtilizationPercentage: 80
  scaleUpCooldownPeriod: 180
  scaleDownCooldownPeriod: 300
  metrics: []

# Persistent storage configuration
persistent:
  pv:
    enabled: false
    volumes:
      - name: "translate-s3-back-pv"
        size: 10Gi
        accessModes:
          - ReadWriteMany
        storageClass: "csi-s3"
        namespace: "special-ns"
        reclaimPolicy: "Retain"
        volumeMode: {}
        nodeAffinity: []
        annotations:
          description: "This is a custom PV for the translate-s3-back"
        claimRef:
          name: "special-claim"
          namespace: "special-ns"
        csi:
          driver: "ru.yandex.s3.csi"
          volumeHandle: "translate-s3-back"
          volumeAttributes:
            capacity: "1Gi"
            mounter: "geesefs"
            options: "--memory-limit=256 --dir-mode=0644 --file-mode=0644 --uid=1000 --gid=1000"
          controllerPublishSecretRef:
            name: "s3-secret"
            namespace: "secret-ns"
          nodePublishSecretRef:
            name: "s3-secret-node-publish"
            namespace: "secret-ns"
          nodeStageSecretRef:
            name: "s3-secret-node-stage"
            namespace: "secret-ns"

# Node selection and scheduling
nodeSelector: {}
tolerations: []
affinity: {}
priorityClassName: ""

# Pod disruption budget
podDisruptionBudget:
  enabled: false
  minAvailable: 1

# Pod termination grace period
terminationGracePeriodSeconds: 30

# Deployment revision history limit
revisionHistoryLimit: 3

# ConfigMap configuration
configs:
  appConfig:
    enabled: true
    name: "app-config"
    mountPath: "/config/app"
    fileName: "app-config.yaml"
    readOnly: false
    data: |
      user nginx;
      worker_processes auto;
      events { worker_connections 1024; }
      http {
        server {
          listen 80;
          server_name localhost;
          location / {
            root /usr/share/nginx/html;
            index index.html index.htm;
          }
        }
      }

# Secrets configuration
secrets:
  dbSecret:
    enabled: true
    name: "db-secret"
    mountPath: "/config/db-secret"
    fileName: "db-secret.yaml"
    readOnly: true
    data: |
      DB_USER: "postgres"
      DB_PASS: "supersecret"

# External secrets configuration
externalSecrets:
  enabled: false
  secretStoreName: "default-secret-store"
  kind: "SecretStore"
  refreshInterval: "1h"
  data:
    - secretKey: "DB_PASSWORD"
      remoteRef:
        key: "database/password"

# Existing ConfigMaps and Secrets
existingConfigs:
  - name: "app-config"
    enabled: true
    namespace: "default"
    mountPath: "/config/app"
    subPath: "app-config.yaml"
    readOnly: true
  - name: "db-config"
    enabled: true
    namespace: "default"
    useEnvFrom: true

existingSecrets:
  - name: "app-secret"
    enabled: true
    namespace: "default"
    mountPath: "/secret/app"
    subPath: "app-secret.env"
    readOnly: true
  - name: "db-secret"
    enabled: true
    namespace: "default"
    envFrom: true

Persistent Storage

This Chart supports persistent storage configuration, including manually specified Persistent Volumes (PVs) and Persistent Volume Claims (PVCs):

persistent:
  pv:
    enabled: true
    volumes:
      - name: "translate-s3-back-pv"
        size: 10Gi
        accessModes:
          - ReadWriteMany
        storageClass: "csi-s3"
        namespace: "special-ns"
        reclaimPolicy: "Retain"
        volumeMode: {}
        nodeAffinity: []
        annotations:
          description: "This is a custom PV for the translate-s3-back"
        claimRef:
          name: "special-claim"
          namespace: "special-ns"
        csi:
          driver: "ru.yandex.s3.csi"
          volumeHandle: "translate-s3-back"
          volumeAttributes:
            capacity: "1Gi"
            mounter: "geesefs"
            options: "--memory-limit=256 --dir-mode=0644 --file-mode=0644 --uid=1000 --gid=1000"
          controllerPublishSecretRef:
            name: "s3-secret"
            namespace: "secret-ns"
          nodePublishSecretRef:
            name: "s3-secret-node-publish"
            namespace: "secret-ns"
          nodeStageSecretRef:
            name: "s3-secret-node-stage"
            namespace: "secret-ns"

Handling Sensitive Data with Secrets

This Helm chart supports Kubernetes Secrets to securely manage sensitive information such as API keys, database passwords, and authentication credentials.

Example Secret configuration:

secrets:
  dbSecret:
    enabled: true
    name: "db-secret"
    mountPath: "/config/db-secret"
    fileName: "db-secret.yaml"
    readOnly: true
    data: |
      DB_USER: "postgres"
      DB_PASS: "supersecret"

Secrets can also be injected as environment variables:

envFrom:
  - secretRef:
      name: "db-secret"

Using Existing ConfigMaps and Secrets

You can use existing ConfigMaps and Secrets from your cluster:

existingConfigs:
  - name: "app-config"
    enabled: true
    namespace: "default"
    mountPath: "/config/app"
    subPath: "app-config.yaml"
    readOnly: true
  - name: "db-config"
    enabled: true
    namespace: "default"
    useEnvFrom: true

existingSecrets:
  - name: "app-secret"
    enabled: true
    namespace: "default"
    mountPath: "/secret/app"
    subPath: "app-secret.env"
    readOnly: true
  - name: "db-secret"
    enabled: true
    namespace: "default"
    envFrom: true

External Secrets

This chart supports external secrets using External Secret Operator (ESO):

externalSecrets:
  enabled: false
  secretStoreName: "default-secret-store"
  kind: "SecretStore"
  refreshInterval: "1h"
  data:
    - secretKey: "DB_PASSWORD"
      remoteRef:
        key: "database/password"

Termination Grace Period

Define how long the pod should wait before termination:

terminationGracePeriodSeconds: 30

Parameters

Common parameters

Name	Description	Value
appVersion	Application version	"1.0.0"
nameOverride	String to partially override common.names.fullname	""
fullnameOverride	String to fully override common.names.fullname	""
namespaceOverride	Override the namespace for all resources	""

Image parameters

Name	Description	Value
image.repository	Container image repository	{}
image.tag	Container image tag	""
image.pullPolicy	Container image pull policy	IfNotPresent
imagePullSecrets	Array of image pull secrets	[]

Deployment parameters

Name	Description	Value
replicaCount	Number of replicas	1
revisionHistoryLimit	Number of deployment revisions to keep	3
podAnnotations	Pod annotations	{}
podLabels	Pod labels	{}
containerSecurityContext	Container security context	{}
podSecurityContext	Pod security context	{}
terminationGracePeriodSeconds	Pod termination grace period	30

Service parameters

Name	Description	Value
service.type	Service type	ClusterIP
service.ports	Service ports configuration	[]

Ingress parameters

Name	Description	Value
ingress.enabled	Enable ingress	false
ingress.className	Ingress class name	""
ingress.annotations	Ingress annotations	{}
ingress.hosts	Ingress hosts configuration	[]
ingress.tls	Ingress TLS configuration	[]

Resource parameters

Name	Description	Value
resources.limits	Resource limits	{}
resources.requests	Resource requests	{}

Autoscaling parameters

Name	Description	Value
autoscaling.enabled	Enable autoscaling	false
autoscaling.minReplicas	Minimum number of replicas	1
autoscaling.maxReplicas	Maximum number of replicas	100
autoscaling.targetCPUUtilizationPercentage	Target CPU utilization	80
autoscaling.targetMemoryUtilizationPercentage	Target memory utilization	80
autoscaling.scaleUpCooldownPeriod	Scale up cooldown period	180
autoscaling.scaleDownCooldownPeriod	Scale down cooldown period	300
autoscaling.metrics	Custom metrics for autoscaling	[]

Storage parameters

Name	Description	Value
persistent.pv.enabled	Enable persistent volumes	false
persistent.pv.volumes	Persistent volume configurations	[]

Service Account parameters

Name	Description	Value
serviceAccount.create	Create service account	false
serviceAccount.automount	Automount service account token	false
serviceAccount.name	Service account name	""

Pod Disruption Budget parameters

Name	Description	Value
podDisruptionBudget.enabled	Enable PDB	false
podDisruptionBudget.minAvailable	Minimum available pods	1

ConfigMap parameters

Name	Description	Value
configs	ConfigMap configurations	{}
existingConfigs	Use existing ConfigMaps	[]

Secret parameters

Name	Description	Value
secrets	Secret configurations	{}
existingSecrets	Use existing Secrets	[]
externalSecrets	External Secret configurations	{}

Node selection parameters

Name	Description	Value
nodeSelector	Node selector for pod placement	{}
tolerations	Pod tolerations	[]
affinity	Pod affinity rules	{}
priorityClassName	Pod priority class name	""

License

This Helm Chart is distributed under the MIT License.