How to use LXD virtual machines

This guide provides step-by-step instructions for setting up, managing, and overseeing LXD VM hosts and virtual machines in MAAS.

Setting up LXD for VM hosts

Remove older LXD versions

sudo apt-get purge -y *lxd* *lxc*
sudo apt-get autoremove -y

Install LXD

sudo snap install lxd
sudo snap refresh

Initialize LXD

sudo lxd init

Follow prompts:

  • Use clustering: no
  • Storage back-end: dir
  • Connect to MAAS: no
  • Use existing bridge: yes
  • Bridge name: br0
  • Trust password: provide password

Disable DHCP for LXD’s bridge

lxc network set lxdbr0 dns.mode=none
lxc network set lxdbr0 ipv4.dhcp=false
lxc network set lxdbr0 ipv6.dhcp=false

Adding a VM host

Add VM host via UI

  1. Navigate to KVM > Add KVM.
  2. Enter required details like Name, LXD address, and select Generate new certificate.
  3. Run the command to add trust to LXD.
  4. Choose Check authentication.
  5. Finalize by selecting Add new project or Select existing project.

Add VM host via CLI

maas $PROFILE vm-host create type=lxd power_address=$LXD_ADDRESS project=$PROJECT_NAME

Managing LXD projects

Create a new LXD project via CLI

  1. Generate API key:
    sudo maas apikey --generate --username admin
  2. Log in:
    maas login admin http://$MAAS_URL/MAAS/api/2.0 $API_KEY
  3. Create VM host with a specific project:
    maas admin vm-hosts create type=lxd power_address=$LXD_ADDRESS project=$PROJECT_NAME

Create and compose a VM in a project

maas $PROFILE vm-host compose $VM_HOST_ID

Move a VM between projects

lxc move $VM_NAME $VM_NAME --project default --target-project $PROJECT_NAME

Overseeing individual VMs

Add a VM via UI

  1. Navigate to KVM > VM host name > Add VM.
  2. Specify details like Name, Cores, RAM, and Disks.
  3. Click Compose machine.

Add a VM via CLI

maas $PROFILE vm-host compose $VM_HOST_ID cores=4 memory=8G disks=1:size=20G

Delete a VM via CLI

maas $PROFILE machine delete $SYSTEM_ID

Network configuration for VM hosts

Set up a bridge via CLI

  1. Create a bridge:
    INTERFACE_ID=$(maas $PROFILE machine read $SYSTEM_ID | jq .boot_interface.id)
BRIDGE_ID=$(maas $PROFILE interfaces create-bridge $SYSTEM_ID name=br0 parent=$INTERFACE_ID | jq .id)
  2. Connect the bridge to a subnet:
    maas $PROFILE interface link-subnet $SYSTEM_ID $BRIDGE_ID subnet=$SUBNET_ID mode="STATIC" ip_address="10.0.0.101"

Set up a bridge with netplan

Edit /etc/netplan/50-cloud-init.yaml to configure the bridge, then apply:

sudo netplan apply

Last updated a month ago.

Help improve this document in the forum.