helm-charts.md

Helm Charts

Defining your extensions as Helm charts is one of two methods you can use to run k0s with your preferred extensions (the other being through the use of Manifest Deployer).

k0s supports two methods for deploying applications using Helm charts:

• Use Helm command in runtime to install applications. Refer to the Helm Quickstart Guide for more information.
• Insert Helm charts directly into the k0s configuration file, k0s.yaml. This method does not require a separate install of helm tool and the charts automatically deploy at the k0s bootstrap phase.

Helm charts in k0s configuration

Adding Helm charts into the k0s configuration file gives you a declarative way in which to configure the cluster. k0s controller manages the setup of Helm charts that are defined as extensions in the k0s configuration file.

Chart install and upgrade options

Charts are processed the same way CLI tool does with following options by default:

• --create-namespace
• --atomic
• --force (only for the upgrade command)
• --wait
• --wait-for-jobs

See Chart configuration below for more details on how to configuring these options.

Repository configuration

Field	Default value	Description
name	(required)	The repository name
url	(required)	The repository URL
insecure	true	Whether to skip TLS certificate checks when connecting to the repository
caFile	-	CA bundle file to use when verifying HTTPS-enabled servers
certFile	-	The TLS certificate file to use for HTTPS client authentication
keyfile	-	The TLS key file to use for HTTPS client authentication
username	-	Username for Basic HTTP authentication
password	-	Password for Basic HTTP authentication

Chart configuration

Field	Default value	Description
name	-	Release name
chartname	-	chartname in form "repository/chartname" or path to tgz file
version	-	version to install
timeout	-	timeout to wait for release install
values	-	yaml as a string, custom chart values
namespace	-	namespace to install chart into
forceUpgrade	true	when set to false, disables the use of the "--force" flag when upgrading the the chart
order	0	order to apply manifest. For equal values, alphanum ordering is used

Example

In the example, Prometheus is configured from "stable" Helms chart repository. Add the following to k0s.yaml and restart k0s, after which Prometheus should start automatically with k0s.

spec:
  extensions:
    helm:
      concurrencyLevel: 5
      repositories:
      - name: stable
        url: https://charts.helm.sh/stable
      - name: prometheus-community
        url: https://prometheus-community.github.io/helm-charts
      - name: helm-repo-with-auth
        url: https://can-be-your-own-gitlab-ce-instance.org/api/v4/projects/PROJECTID/packages/helm/main
        username: access-token-name-as-username
        password: access-token-value-as-password
      charts:
      - name: prometheus-stack
        chartname: prometheus-community/prometheus
        version: "14.6.1"
        timeout: 20m
        order: 1
        values: |
          alertmanager:
            persistentVolume:
              enabled: false
          server:
            persistentVolume:
              enabled: false
        namespace: default
      # We don't need to specify the repo in the repositories section for OCI charts
      - name: oci-chart
        chartname: oci://registry:8080/chart
        version: "0.0.1"
        order: 2
        values: ""
        namespace: default
      # Other way is to use local tgz file with chart
      # the file must exist on all controller nodes
      - name: tgz-chart
        chartname: /tmp/chart.tgz
        version: "0.0.1"
        order: 2 
        values: ""
        namespace: default

Example extensions that you can use with Helm charts include:

• Ingress controllers: Nginx ingress, Traefix ingress (refer to the k0s documentation for Installing the Traefik Ingress Controller)
• Volume storage providers: OpenEBS, Rook, Longhorn
• Monitoring: Prometheus, Grafana

Helm debug logging

Running k0s controller with --debug=true enables helm debug logging.