Ansible Role: microk8s

Role to download and install microk8s the smallest, simplest, pure production K8s.

Requirements

• Ansible >= 2.7
• Linux Distribution
  • Debian Family
    • Ubuntu
      • Xenial (16.04)
      • Bionic (18.04)
      • Focal (20.04) (untested)
      • Jammy (22.04) (untested)
  • Arch Linux (untested)

License

MIT

Usage

Role Variables

Some variables available in this role are listed here. The full set is defined in [defaults/main.yml](defaults/main.yml).

• microk8s_version: Version to use, defaults to 1.27/stable.
• microk8s_plugins: Enable/disable various plugins. A string will be passed as arg when enabling addon using name:arg
• microk8s_enable_HA: Enable/disable high-availability.
• microk8s_group_HA: Hostgroup whose members will form HA cluster.
• microk8s_group_WORKERS: Hostgroup whose members will act as worker nodes only (no control-plane components run here)
• microk8s_csr_template: If defined, will cause a custom CSR to be used in generating certificates.

Basic playbook

- hosts: servers
  roles:
    - role: istvano.microk8s
      vars:
        microk8s_plugins:
          dns: "1.1.1.1"
          istio: true
          ingress: true

Note: when overriding plugins list, it is recommended to copy-paste the entire list of plugins from the defaults/main.yml because some Ansible tasks reference them (e.g. helm3) and the deployment may fail.

Custom certificate request template

It might be useful to customize the certificate request template used by MicroK8s in generating cluster certificates. For example, additional SANs can be added to the certificates such that the MicroK8s certificates validate when addressed from outside the cluster, such as through a reverse proxy.

To generate a CSR template, the easiest is probably to use the role without a template, and then copy the CSR in /var/snap/microk8s/current/certs/csr.conf.template to your playbook's templates directory, make the edits and set the microk8s_csr_template variable accordingly, and re-run the playbook.

Adding worker only nodes (1.23+ only)

It is possible to configure additional nodes to act as workers only within your microk8s cluster. This is possible by configuring the ansible hostgroup microk8s_WORKERS (name of the group is configurable via microk8s_group_WORKERS). Every host listed within the hostgroup will essentially run microk8s join .... --worker, more info on this can be found here: microk8s-clustering.

Testing

Using Molecule wrapper and system Python

• ./moleculew lint
• ./moleculew create
• ./moleculew list
• ./moleculew check
• ./moleculew test

Using Python virtual environment

• Set up virtual environment

  $ python3 -m venv venv
  

• Activate the environment

  $ . venv/bin/activate
  

• Install Molecule with lint and Docker options

  $ pip install 'molecule[lint,docker]'
  

• Install up-to-date Ansible package if necessary

  $ pip install ansible
  

• Run the test commands:
  • molecule lint
  • molecule create
  • molecule list
  • molecule check
  • molecule test