🗲 Ride the Lightning!🗲

Virt-Lightning can quickly deploy a bunch of new VM. It also prepares the Ansible inventory file!

This is handy to quickly validate a new Ansible playbook, or a role on a large number of environments.

example: test an Ansible command on a new env in ONE minute ⚡

In a nutshell:

echo "- distro: centos-7" > virt-lightning.yaml
vl up
vl ansible_inventory
ansible all -m ping -i inventory

In the video below, we:

1. use the list of distribution to generate a virt-lightning.yaml file.
2. we then create a environment based on this file
3. once the environment is ready, we generate an Ansible inventory file
4. and we use it to call Ansible's ping module on all the host.

Pre-requirements

Debian

First you need to install libvirt and guestfs:

sudo apt install -f libvirt-daemon libvirt-daemon-system python3 python3-libvirt python3-pip python3-urwid
sudo systemctl start --now libvirtd

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G kvm,libvirt,libvirt-qemu $USER

Fedora-29 and after

First you need to install libvirt and guestfs:

sudo dnf install -f libselinux-python libvirt libvirt-daemon python3 python3-libvirt python3-pip python3-urwid
sudo systemctl start --now libvirtd

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G qemu,libvirt $USER

Ubuntu-16.04

First you need to install libvirt and guestfs:

sudo apt install -f libvirt-bin libvirt-daemon python3 python3-libvirt python3-pip python3-urwid
sudo systemctl start --now libvirtd

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G kvm,libvirtd $USER

Ubuntu-18.04

First you need to install libvirt and guestfs:

sudo apt install -f libvirt-bin libvirt-daemon python3 python3-libvirt python3-pip python3-urwid
sudo systemctl start --now libvirtd

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G kvm,libvirt $USER

Ubuntu-18.10 and after

First you need to install libvirt and guestfs:

sudo apt install -f libvirt-daemon libvirt-daemon-system python3 python3-libvirt python3-pip python3-urwid
sudo systemctl start --now libvirtd

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G kvm,libvirt $USER

RHEL-8

First you need to install libvirt and guestfs:

sudo apt install -f python3-libvirt libvirt qemu-kvm libvirt-daemon-kvm genisoimage
sudo systemctl start --now libvirtd

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G libvirt $USER

Void Linux

First you need to install libvirt and guestfs:

sudo xbps-install -Rs libvirt libvirt-python3 qemu python3-pip cdrtools dbus
sudo ln -s /etc/sv/dbus /var/service
sudo ln -s /etc/sv/libvirtd /var/service
sudo ln -s /etc/sv/virtlockd /var/service
sudo ln -s /etc/sv/virtlogd /var/service

The second step is to grant to your user the ability to use libvirt:

sudo usermod -a -G kvm,libvirt $USER

Installation

pip3 install --user virt-lightning

If you use Ubuntu, you will need the --no-deps argument (See: pypa/pip#4222).

virt-lightning will be installed in ~/.local/bin/. Add it in your $PATH if it's not already the case. For instance if you use:

echo "export PATH=$PATH:~/.local/bin/" >> ~/.bashrc
source ~/.bashrc

Fetch some images

Before you start your first VM, you need to fetch the images. To do so, you just use the vm fetch command:

$ vl fetch fedora-30

Build your images

If you prefer to build your own images,

$ git clone https://github.com/virt-lightning/virt-lightning
$ cd virt-lightning/images
$ ./image centos-7 build
$ ./image debian-9 build
(…)

Ubuntu requires the use sudo to build or prepare images.

You can also use your own images as soon as they embed cloud-init, just copy them in the QCOW2 format in /var/lib/virt-lightning/pool/upstream/. It's also a good idea to include qemu-guest-agent, virt-lightning uses it to set the root password and it offers some other benefits.

Actions

vl is an alias for virt-lightning, you can us both. In the rest of the document we use the shortest version.

vl distro_list

List the distro images that can be used. Its output is compatible with vl up. You can initialize a new configuration with: vl distro > virt-lightning.yaml.

vl up

virt-lightning will read the virt-lightning.yaml file from the current directory and prepare the associated VM.

vl down

Destroy all the VM managed by Virt-Lightning.

vl start

Start a specific VM, without reading the virt-lightning.yaml file.

vl stop

Stop just one VM.

vl status

List the VM, their IP and if they are reachable.

vl ansible_inventory

Export an inventory in the Ansible format.

vl ssh

Show up a menu to select a host and open a ssh connection.

vl console

Like vl ssh but with the serial console of the VM.

vl viewer

Like vl console but with the SPICE console of the VM. Requires virt-viewer.

vl fetch

Fetch a VM image. You can find here a list of the available images.

Configuration

Global configuration

If ~/.config/virt-lightning/config.ini exists, Virt-Lightning will read its configuration there.

[main]
network_name = virt-lightning
root_password = root
storage_pool = virt-lightning
network_auto_clean_up = True

network_name: if you want to use an alternative libvirt network

root_password: the root password

storage_pool: if you want to use an alternative libvirt storage pool

network_auto_clean_up: if you want to automatically remove a network when running virt-lightning down

VM configuration keys

A VM can be tunned at two different places with the following keys:

• distro: the name of the base distro image to use, it's the only mandatory parameter.
• name: the VM name
• memory: the amount of memory to dedicate to the VM
• root_disk_size: the size of the root disk in GB
• vcpus: the number of vcpu to dedicate to the VM
• root_password: the root password in clear text
• groups: this list of groups will be used if you generate an Ansible inventory.
• networks: a list of network to attach to the VM. The default is: one virtio interface attached to virt-lightning network.
  • network: the name of the network. Default is virt-lightning
  • ipv4: a static IPv4, this key is only accepted for the first network. Default is a dynamic IPv4 address.
  • nic_model: the libvirt driver to use. Default is virtio

Example: a virt-lightning.yaml file:

- name: esxi-vcenter
  distro: esxi-6.7
  memory: 12000
  root_disk_size: 30
  vcpus: 2
  root_password: '!234AaAa56'
  groups: ['all_esxi']
- name: esxi1
  distro: esxi-6.7
  memory: 4096
  vcpus: 1
  root_password: '!234AaAa56'
  groups: ['all_esxi', 'esxi_lab']
- name: esxi2
  distro: esxi-6.7
  memory: 4096
  vcpus: 1
  root_password: '!234AaAa56'
  groups: ['all_esxi', 'esxi_lab']
- name: centos-7
  distro: centos-7
  networks:
    - network: default
      ipv4: 192.168.122.50
  bootcmd:
    - yum update -y

You can also associate some parameters to the distro image itself

cat /var/lib/virt-lightning/pool/upstream/esxi-6.7.yaml
username: root
python_interpreter: /bin/python
memory: 4096
networks:
  - network: virt-lightning
    nic_model: virtio
  - network: default
    nic_model: e1000