Ansible Role: k0s

Create a Kubernetes Cluster using Ansible.

Use vanilla upstream Kubernetes distro k0s.

Similar to movd/k0s-ansible, but better (i think so ;) )

If latest is set for k0s_version, the role tries to install the latest release version.
Please use this with caution, as incompatibilities between releases may occur!

The binaries are installed below /usr/local/bin/k0s/${k0s_version} and later linked to /usr/bin.
This should make it possible to downgrade relatively safely.

The k0s archive is stored on the Ansible controller, unpacked and then the binaries are copied to the target system. The cache directory can be defined via the environment variable CUSTOM_LOCAL_TMP_DIRECTORY.
By default it is ${HOME}/.cache/ansible/k0s.
If this type of installation is not desired, the download can take place directly on the target system.
However, this must be explicitly activated by setting k0s_direct_download to true.

Requirements & Dependencies

Ansible Collections

• bodsch.core
• bodsch.scm

ansible-galaxy collection install bodsch.core
ansible-galaxy collection install bodsch.scm

or

ansible-galaxy collection install --requirements-file collections.yml

Why better?

This Ansible role can be used atomically.
If no changes are necessary, none will be made.

Avoid command calls.
Wherever possible, separate Ansible modules are used for this.

One role for all cases.

supported Operating systems

Tested on

• ArchLinux
• Debian based
  • Debian 10 / 11 / 12
  • Ubuntu 20.04 / 22.04 / 24.04

working implementation

The example of a working implementation can be viewed at GitLab.
A suitable infrastructure based on KVM and Terraform can be created in the repository.

There are some tests in molecule that could be used. For reasons that are not clear to me, the tests in a docker container are not very meaningful. I have therefore extended the tests with the Vagrant driver.

There is a Makefile to start the tests:

make test -e TOX_SCENARIO=multi-worker

make test -e TOX_SCENARIO=vagrant-multi-worker

Contribution

Please read Contribution

Development, Branches (Git Tags)

The master Branch is my Working Horse includes the "latest, hot shit" and can be complete broken!

If you want to use something stable, please use a Tagged Version!

usage

k0s_version: 1.25.2+k0s.0
k0s_release_download_url: https://github.com/k0sproject/k0s/releases

k0s_system_user: k0s
k0s_system_group: k0s

k0s_config_dir: /etc/k0s
k0s_data_dir: /var/lib/k0s
k0s_libexec_dir: /usr/libexec/k0s

k0s_direct_download: false

k0s_worker_on_controller: false
k0s_no_taints: false

k0s_force: false
k0s_debug: false
k0s_verbose: false

k0s_cluster_nodes:
  initial_controller: ""
  controllers: []
  workers: []

k0s_extra_arguments:
  controller:
    - --enable-metrics-scraper

k0s_config_overwrites: {}

k0s_token_expiry: "15m"

k0s_artifacts_dir: "{{ inventory_dir }}/artifacts"

k0s_config_overwrites

Extension of the automatically created k0s.yaml The structure must correspond to the created configuration. An example file can be viewed here.

single controller

k0s_cluster_nodes:
  initial_controller: controller-1.k0s.local
  controllers: []
  workers: []

one controller with multi workers

k0s_cluster_nodes:
  initial_controller: controller-1.k0s.local
  controllers: []
  workers:
    - worker-1.k0s.local
    - worker-2.k0s.local
    - worker-3.k0s.local

multi controllers with multi workers

k0s_cluster_nodes:
  initial_controller: controller-1.k0s.local
  controllers:
    - controller-2.k0s.local
    - controller-3.k0s.local
  workers:
    - worker-1.k0s.local
    - worker-2.k0s.local
    - worker-3.k0s.local

Credits

• Moritz

other dokumentaions

Upgrading a k0s cluster in-place from single-master to HA