Creating an Incus Instance with cloud‑init

To verify that an Ansible role works correctly I need to test it on multiple instances with Molecule. I require, to accomplish this, an SSH server, a sudo user that allows SSH login with my public key, and a few missing packages. Rather than creating a separate model for each Linux distribution and repeating the process with every new release, I’ll use an Incus profile with cloud‑init to deploy the same configuration everywhere.

To do this we must first have Incus configured.

To create and edit the Molecule profile, run:

incus profile create molecule
incus profile edit molecule

In the profile‑editing window:

### This is a YAML representation of the profile.
### Any line starting with a '#' will be ignored.
###
### A profile consists of a set of configuration items followed by a set of
### devices.
###
### An example would look like:
### name: onenic
### config:
###   raw.lxc: lxc.aa_profile=unconfined
### devices:
###   eth0:
###     nictype: bridged
###     parent: mybr0
###     type: nic
###
### Note that the name is shown but cannot be changed

config:
  cloud-init.user-data: |
    #cloud-config
    package_upgrade: true
    packages:
      - acl
      - openssh-server
      - python3-apt
    users:
      - name: ansible
        groups: sudo
        sudo: ALL=(ALL) NOPASSWD:ALL
        shell: /bin/bash
        ssh_authorized_keys:
          - ssh-ed25519 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXX
description: ""
devices: {}
name: molecule
used_by: []

In order, package_upgrade updates the Apt packages, then packages installs the selected packages, and finally a user is created with the name ansible, added to the sudo group, configured for password‑less sudo, and given an SSH public key for login. You can find further references for configuring the file in the official documentation.

Once configured you can launch a test instance with:

incus launch images:debian/trixie/cloud test-cloud-init --profile default --profile molecule