cloud-init#

LXD supports cloud-init via the following instance or profile configuration keys

cloud-init.vendor-data
cloud-init.user-data
cloud-init.network-config

Before trying to use it, however, first determine which image source you are about to use as not all images have the cloud-init package installed.

The images from the ubuntu and ubuntu-daily remotes are all cloud-init enabled. Images from the images remote have cloud-init enabled variants using the /cloud suffix, e.g. images:ubuntu/22.04/cloud.

Both vendor-data and user-data follow the same rules, with the following caveats:

Users have ultimate control over vendordata. They can disable its execution or disable handling of specific parts of multipart input.
By default it only runs on first boot
Vendordata can be disabled by the user. If the use of vendordata is required for the instance to run, then vendordata should not be used.
user supplied cloud-config is merged over cloud-config from vendordata.

For LXD instances, vendor-data should be used in profiles rather than the instance config.

Cloud-config examples can be found here: https://cloudinit.readthedocs.io/en/latest/topics/examples.html

Custom network configuration#

cloud-init uses the network-config data to render the relevant network configuration on the system using either ifupdown or netplan depending on the Ubuntu release.

The default behavior is to use a DHCP client on an instance’s eth0 interface.

In order to change this you need to define your own network configuration using cloud-init.network-config key in the config dictionary which will override the default configuration (this is due to how the template is structured).

For example, to configure a specific network interface with a static IPv4 address and also use a custom nameserver use

config:
  cloud-init.network-config: |
    version: 1
    config:
      - type: physical
        name: eth1
        subnets:
          - type: static
            ipv4: true
            address: 10.10.101.20
            netmask: 255.255.255.0
            gateway: 10.10.101.1
            control: auto
      - type: nameserver
        address: 10.10.10.254

An instance’s rootfs will contain the following files as a result:

/var/lib/cloud/seed/nocloud-net/network-config
/etc/network/interfaces.d/50-cloud-init.cfg (if using ifupdown)
/etc/netplan/50-cloud-init.yaml (if using netplan)