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
helmtool 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.
Wait for install#
Each chart is proccesed the same way CLI tool does with following options:
It is possible to customize timeout by using
|chartname||-||chartname in form "repository/chartname" or path to tgz file|
|version||-||version to install|
|timeout||10m||timeout to wait for release install|
|values||-||yaml as a string, custom chart values|
|namespace||-||namespace to install chart into|
|order||0||order to apply manifest. For equal values, alphanum ordering is used|
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 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.