Generic helm chart for applications which:

• are stateless
• creates only namespace scoped resources (e.g. it doesn't need CRB - Cluster Role Bindings)
• don't need privileged containers
• don't call the underlying Kubernetes API or use the underlying etcd as a database by defining custom resources
• run either as deployment, job or cronjob

To install the chart with the release name my-application in namespace test:

helm repo add stakater https://stakater.github.io/stakater-charts
helm repo update
helm install my-application stakater/application --namespace test

To uninstall the chart:

helm delete --namespace test my-application

Name format of ConfigMap, Secret, SealedSecret and ExternalSecret is {{ template "application.name" $ }}-{{ $nameSuffix }} then:

• {{ template "application.name" }} is a helper function that outputs .Values.applicationName if exist else return chart name as output
• nameSuffix is the each key in secret.files, configMap.files, sealedSecret.files and externalSecret.files

For example if we have following values file:

applicationName: helloworld # {{ template "application.name" $ }}

configMap:
  files:
    config: # {{ $nameSuffix }}
      key: value

then the configmap name will be named helloworld-config.

In order to use environment variable in deployment or cronjob, you will have to provide environment variable in key/value pair in env value. where key being environment variable key and value varies in different scenarios

• For simple key/value environment variable, just provide value: <value>

  env:
    KEY:
      value: MY_VALUE

• To get environement variable value from ConfigMap

  Suppose we have a configmap created from application chart

  applicationName: my-application
  configMap:
    enabled: true
    files:
      application-config:
        LOG: DEBUG
        VERBOSE: v1

  To get environment variable value from above created configmap, we will need to add following

  env:
   APP_LOG_LEVEL:
    valueFrom:
      configMapKeyRef:
        name: my-application-appication-config
        key: LOG

  To get all environment variables key/values from ConfigMap, where configmap key being key of environment variable and value being value

  envFrom:
    application-config-env:
      type: configmap
      nameSuffix: application-config

  You can either provide nameSuffix which means name added after prefix <applicationName>- or static name with name of configmap.

• To get environment variable value from Secret

  Suppose we have secret created from application chart

  applicationName: my-application
  secret:
    enabled: true
    files:
       db-credentials:
         PASSWORD: skljd#2Qer!!
         USER: postgres

  To get environment variable value from above created secret, we will need to add following

  env:
    KEY:
      valueFrom:
      secretKeyRef:
        name: my-application-db-credentials
        key: USER

  To get environement variable value from Secret, where secret key being key of environment variable and value being value

  envFrom:
    database-credentials:
       type: secret
       nameSuffix: db-credentials

  you can either provide nameSuffix which means name added after prefix <applicationName>- or static name with name of secret

  Note: first key after envFrom is just used to uniquely identify different objects in envFrom block. Make sure to keep it unique and relevant

To disable liveness or readiness probe, set value of enabled to false.

livenessProbe:
  enabled: false

By default probe handler type is httpGet. You just need to override port and path as per your need.

livenessProbe:
  enabled: true
  httpGet:
    path: '/path'
    port: 8080

In order to use exec handler, you can define field livenessProbe.exec in your values.yaml.

livenessProbe:
  enabled: true
  exec:
    command:
      - cat
      - /tmp/healthy