Autoinstall configuration reference manual¶
The autoinstall file uses the YAML format. At the top level is a single key, autoinstall
, which contains a mapping of the keys described in this document. Unrecognised keys are ignored in version 1, but they will cause a fatal validation error in future versions.
Here is an example of a minimal autoinstall configuration:
autoinstall:
version: 1
identity:
...
At the top level is the autoinstall
keyword. It contains a version
section and an (incomplete) identity
section, which are explained in more detail below. Any other key at the level of autoinstall
results in an autoinstall validation error at run time.
Note
This behaviour was first introduced during 24.04 (Noble). On any ISOs built before 24.04, you need to refresh the installer to see this behaviour.
Technically, in all but one case the top level autoinstall
keyword is strictly unnecessary. This keyword is only necessary when serving autoinstall via cloud-config. For backwards compatibility, this format is still supported for delivery methods not based on cloud-config; however, it is highly recommended to use the format with a top-level autoinstall
keyword because mistakes in this formatting are a common source of confusion.
Schema¶
Autoinstall configurations are validated against a JSON schema before they are used.
Command lists¶
Several configuration keys are lists of commands to be executed. Each command can be a string (in which case it is executed via sh -c
) or a list, in which case it is executed directly. Any command exiting with a non-zero return code is considered an error and aborts the installation (except for error-commands, where it is ignored).
Top-level keys¶
The following keys can be used to configure various aspects of the installation. If the global autoinstall
key is provided, then all “top-level keys” must be provided underneath it and “top-level” refers to this sub-level. The examples below demonstrate this structure.
Warning
In version 1, Subiquity emits warnings when encountering unrecognised keys. In later versions, it results in a fatal validation error, and the installation halts.
version¶
type: integer
default: no default
A future-proofing configuration file version field. Currently, this must be 1
.
interactive-sections¶
type: list of strings
default: []
A list of configuration keys to still show in the user interface (UI). For example:
autoinstall:
version: 1
interactive-sections:
- network
identity:
username: ubuntu
password: $crypted_pass
This example stops on the network screen and allows the user to change the defaults. If a value is provided for an interactive section, it is used as the default.
You can use the special section name of *
to indicate that the installer should ask all the usual questions – in this case, the autoinstall.yaml
file is an autoinstall file. It just provides a way to change the defaults in the UI.
Not all configuration keys correspond to screens in the UI. This documentation indicates if a given section can be interactive or not.
If there are any interactive sections at all, the reporting key is ignored.
early-commands¶
type: command list
default: no commands
can be interactive: no
A list of shell commands to invoke as soon as the installer starts, in particular before probing for block and network devices. The autoinstall configuration is available at /autoinstall.yaml
(irrespective of how it was provided), and the file is re-read after the early-commands
have run to allow them to alter the configuration if necessary.
locale¶
type: string
default:
en_US.UTF-8
can be interactive: true
The locale to configure for the installed system.
refresh-installer¶
type: mapping
default: see below
can be interactive: true
Controls whether the installer updates to a new version available in the given channel before continuing.
The mapping contains keys:
update¶
type: boolean
default:
false
Whether to update or not.
channel¶
type: string
default:
"stable/ubuntu-$REL"
The channel to check for updates.
keyboard¶
type: mapping, see below
default: US English keyboard
can be interactive: true
The layout of any attached keyboard. The mapping keys correspond to settings in the /etc/default/keyboard
configuration file. See the keyboard(5) manual page for more details.
The mapping contains keys:
layout¶
type: string
default:
"us"
Corresponds to the XKBLAYOUT
setting.
variant¶
type: string
default:
""
Corresponds to the XKBVARIANT
setting.
toggle¶
type: string or null
default:
null
Corresponds to the value of grp:
option from the XKBOPTIONS
setting. Acceptable values are (the installer does not validate these):
caps_toggle
toggle
rctrl_toggle
rshift_toggle
rwin_toggle
menu_toggle
alt_shift_toggle
ctrl_shift_toggle
ctrl_alt_toggle
alt_caps_toggle
lctrl_lshift_toggle
lalt_toggle
lctrl_toggle
lshift_toggle
lwin_toggle
sclk_toggle
Warning
The version of Subiquity released with 20.04 GA does not accept null
for this field due to a bug.
source¶
type: mapping, see below
default: see below
can be interactive: true
search_drivers¶
type: boolean
default:
true
(mostly, see below)
Whether the installer searches for available third-party drivers. When set to false
, it disables the drivers screen and section.
The default is true
for most installations, and false
when a “core boot” or “enhanced secure boot” method is selected (where third-party drivers cannot be currently installed).
id¶
type: string
default: identifier of the first available source.
Identifier of the source to install (e.g., ubuntu-server-minimal
).
network¶
type: Netplan-format mapping, see below
default: DHCP on interfaces named
eth*
oren*
can be interactive: true
Netplan-formatted network configuration. This is applied during installation as well as in the installed system. The default is to interpret the configuration for the installation media, which runs DHCP version 4 on any interface with a name matching eth*
or en*
but then disables any interface that does not receive an address.
For example, to run DHCP version 6 on a specific network interface:
autoinstall:
network:
version: 2
ethernets:
enp0s31f6:
dhcp6: true
Note that in the 20.04 GA release of Subiquity, the behaviour is slightly different and requires you to write this with an extra network:
key:
autoinstall:
network:
network:
version: 2
ethernets:
enp0s31f6:
dhcp6: true
Versions later than 20.04 support this syntax, too (for compatibility). When using a newer version, use the regular syntax.
proxy¶
type: URL or
null
default: no proxy
can be interactive: true
The proxy to configure both during installation and for apt
and snapd
in the target system.
apt¶
type: mapping
default: see below
can be interactive: true
APT configuration, used both during the installation and once booted into the target system.
This section historically used the same format as curtin, which is documented in the APT Source section of the curtin documentation. Nonetheless, some key differences with the format supported by curtin have been introduced:
Subiquity supports an alternative format for the
primary
section, allowing configuration of a list of candidate primary mirrors. During installation, Subiquity automatically tests the specified mirrors and selects the first one that appears usable. This new behaviour is only activated when theprimary
section is wrapped in themirror-selection
section.The
fallback
key controls what Subiquity does when no primary mirror is usable.The
geoip
key controls whether to perform IP-based geolocation to determine the correct country mirror.
The default is:
autoinstall:
apt:
preserve_sources_list: false
mirror-selection:
primary:
- country-mirror
- arches: [i386, amd64]
uri: "http://archive.ubuntu.com/ubuntu"
- arches: [s390x, arm64, armhf, powerpc, ppc64el, riscv64]
uri: "http://ports.ubuntu.com/ubuntu-ports"
fallback: abort
geoip: true
mirror-selection¶
If the primary
section is contained within the mirror-selection
section, the automatic mirror selection is enabled. This is the default in new installations.
primary (when placed inside the mirror-selection
section)¶
type: custom, see below
In the new format, the primary
section expects a list of mirrors, which can be expressed in two different ways:
The special
country-mirror
valueA mapping with the following keys:
uri
: The URI of the mirror to use, e.g.,http://fr.archive.ubuntu.com/ubuntu
.arches
: An optional list of architectures supported by the mirror. By default, this list contains the current CPU architecture.
fallback¶
type: string (enumeration)
default: offline-install
Controls what Subiquity does when no primary mirror is usable. Supported values are:
abort
: abort the installationoffline-install
: revert to an offline installationcontinue-anyway
: attempt to install the system anyway (not recommended; the installation fails)
geoip¶
type: boolean
default:
true
If geoip
is set to true
and one of the candidate primary mirrors has the special value country-mirror
, a request is made to https://geoip.ubuntu.com/lookup
. Subiquity then sets the mirror URI to http://CC.archive.ubuntu.com/ubuntu
(or similar for ports) where CC
is the country code returned by the lookup. If this section is not interactive, the request expires after 10 seconds.
If the legacy behaviour (i.e., without mirror-selection) is in use, the geolocation request is made if the mirror to be used is the default, and its URI is replaced by the proper country mirror URI.
To specify a mirror, use a configuration like this:
autoinstall:
apt:
mirror-selection:
primary:
- uri: YOUR_MIRROR_GOES_HERE
- country-mirror
- uri: http://archive.ubuntu.com/ubuntu
To add a PPA:
autoinstall:
apt:
sources:
curtin-ppa:
source: ppa:curtin-dev/test-archive
storage¶
type: mapping, see below
default: use the
lvm
layout on single-disk systems; there is no default for multiple-disk systemscan be interactive: true
Storage configuration is a complex topic, and the description of the desired configuration in the autoinstall file can also be complex. The installer supports “layouts”; simple ways of expressing common configurations.
Supported layouts¶
The three supported layouts at the time of writing are lvm
, direct
and zfs
.
autoinstall:
storage:
layout:
name: lvm
storage:
layout:
name: direct
storage:
layout:
name: zfs
By default, these layouts install to the largest disk in a system, but you can supply a match spec (see below) to indicate which disk to use:
autoinstall:
storage:
layout:
name: lvm
match:
serial: CT*
storage:
layout:
name: direct
match:
ssd: true
Note
Match spec – using match: {}
matches an arbitrary disk.
When using the lvm
layout, LUKS encryption can be enabled by supplying a password.
autoinstall:
storage:
layout:
name: lvm
password: LUKS_PASSPHRASE
The default is to use the lvm
layout.
Sizing-policy¶
The lvm
layout, by default, attempts to leave room for snapshots and further expansion. A sizing-policy key may be supplied to control this behaviour.
type: string (enumeration)
default: scaled
Supported values are:
scaled
: Adjust space allocated to the root logical volume (LV) based on space available to the volume group (VG).all
: Allocate all remaining VG space to the root LV.
The scaling system uses the following rules:
Less than 10 GiB: use all remaining space for the root file system
Between 10–20 GiB: 10 GiB root file system
Between 20–200 GiB: use half of the remaining space for the root file system
Greater than 200 GiB: 100 GiB root file system
Example with no size scaling and a passphrase:
autoinstall:
storage:
layout:
name: lvm
sizing-policy: all
password: LUKS_PASSPHRASE
Reset Partition¶
reset-partition
is used for creating a Reset Partition, which is a FAT32 file system containing the entire content of the installer image, so that the user can start the installer from GRUB or EFI without using the installation media. This option is useful for OEM system provisioning.
By default, the size of a Reset Partition is roughly 1.1x the used file system size of the installation media.
An example to enable Reset Partition:
autoinstall:
storage:
layout:
name: direct
reset-partition: true
The size of the reset partition can also be fixed to a specified size. This is an example to fix Reset Partition to 12 GiB:
autoinstall:
storage:
layout:
name: direct
reset-partition: 12G
The installer can also install Reset Partition without installing the system. To do this, set reset-partition-only
to true
:
autoinstall:
storage:
layout:
name: direct
reset-partition: true
reset-partition-only: true
Action-based configuration¶
For full flexibility, the installer allows storage configuration to be done using a syntax that is a superset of that supported by curtin, as described in the Storage section of the curtin documentation.
If the layout
feature is used to configure the disks, the config
section is not used.
The list of actions can be added under the config
key, and the grub and swap
curtin configuration items can also be included here.
An example storage section:
autoinstall:
storage:
swap:
size: 0
config:
- type: disk
id: disk0
serial: ADATA_SX8200PNP_XXXXXXXXXXX
- type: partition
...
The extensions to the curtin syntax allow for disk selection and partition or logical-volume sizing.
Disk selection extensions¶
Curtin supported identifying disks by serial numbers (e.g. Crucial_CT512MX100SSD1_14250C57FECE
) or by path (e.g. /dev/sdc
), and the server installer supports this, too. The installer additionally supports a “match spec” on a disk action, which provides for more flexible matching.
The actions in the storage configuration are processed in the order they are in the autoinstall file. Any disk action is assigned a matching disk – chosen arbitrarily from the set of unassigned disks if there is more than one, and causing the installation to fail if there is no unassigned matching disk.
A match spec supports the following keys:
model: value
: matches a disk whereID_MODEL=value
in udev, supporting globbingvendor: value
: matches a disk whereID_VENDOR=value
in udev, supporting globbingpath: value
: matches a disk based on path (e.g./dev/sdc
), supporting globbing (the globbing support distinguishes this from specifyingpath: value
directly in the disk action)id_path: value
: matches a disk whereID_PATH=value
in udev, supporting globbingdevpath: value
: matches a disk whereDEVPATH=value
in udev, supporting globbingserial: value
: matches a disk whereID_SERIAL=value
in udev, supporting globbing (the globbing support distinguishes this from specifyingserial: value
directly in the disk action)ssd: true|false
: matches a disk that is or is not an SSD (as opposed to a rotating drive)size: largest|smallest
: take the largest or smallest disk rather than an arbitrary one if there are multiple matches (support forsmallest
added in version 20.06.1)
A special sort of key is install-media: true
, which takes the disk the installer was loaded from (the ssd
and size
selectors never return this disk). If installing to the installation media, be careful to not overwrite the installer itself.
For example, to match an arbitrary disk:
- type: disk
id: disk0
To match the largest SSD:
- type: disk
id: big-fast-disk
match:
ssd: true
size: largest
To match a Seagate drive:
- type: disk
id: data-disk
match:
model: Seagate
Partition/logical volume extensions¶
The size of a partition or logical volume in curtin is specified as a number of bytes. The autoinstall configuration is more flexible:
You can specify the size using the
1G
,512M
syntax supported in the installer UI.You can specify the size as a percentage of the containing disk (or RAID), e.g.
50%
.For the last partition specified for a particular device, you can specify the size as
-1
to indicate that the partition should fill the remaining space.
- type: partition
id: boot-partition
device: root-disk
size: 10%
- type: partition
id: root-partition
size: 20G
- type: partition
id: data-partition
device: root-disk
size: -1
identity¶
type: mapping, see below
default: no default
can be interactive: true
Configure the initial user for the system. This is the only configuration key that must be present (unless the user-data section is present, in which case it is optional).
A mapping that can contain keys, all of which take string values:
realname¶
The real name for the user. This field is optional.
username¶
The user name to create.
hostname¶
The hostname for the system.
password¶
The password for the new user, encrypted. This is required for use with sudo
, even if SSH access is configured.
The encrypted password string must conform to what the passwd
command requires. See the passwd(1) manual page for details. Quote the password hash to ensure correct treatment of any special characters.
Several tools can generate the encrypted password, such as mkpasswd
from the whois
package, or openssl passwd
.
Example:
autoinstall:
identity:
realname: 'Ubuntu User'
username: ubuntu
password: '$6$wdAcoXrU039hKYPd$508Qvbe7ObUnxoj15DRCkzC3qO7edjH0VV7BPNRDYK4QR8ofJaEEF2heacn0QgD.f8pO8SNp83XNdWG6tocBM1'
hostname: ubuntu
active-directory¶
type: mapping, see below
default: no default
can be interactive: true
Accepts data required to join the target system in an Active Directory domain.
A mapping that can contain keys, all of which take string values:
admin-name¶
A domain account name with the privilege to perform the join operation. The account password is requested during run time.
domain-name¶
The Active Directory domain to join.
ubuntu-pro¶
type: mapping, see below
default: see below
can be interactive: true
token¶
type: string
default: no token
A contract token to attach to an existing Ubuntu Pro subscription.
ssh¶
type: mapping, see below
default: see below
can be interactive: true
Configure SSH for the installed system. A mapping that can contain the following keys:
install-server¶
type: boolean
default:
false
Whether to install the OpenSSH server in the target system.
allow-pw¶
type: boolean
default:
true
ifauthorized_keys
is empty,false
otherwise
codecs¶
type: mapping, see below
default: see below
can be interactive: no
Configure whether common restricted packages (including codecs) from the multiverse repository are to be installed.
install¶
type: boolean
default:
false
Whether to install the ubuntu-restricted-addons
package.
drivers¶
type: mapping, see below
default: see below
can be interactive: true
install¶
type: boolean
default:
false
Whether to install the available third-party drivers.
oem¶
type: mapping, see below
default: see below
can be interactive: no
install¶
type: boolean or string (special value
auto
)default::
auto
Whether to install the available OEM meta-packages. The special value auto
– which is the default – enables the installation on Ubuntu Desktop but not on Ubuntu Server. This option has no effect on core boot classic.
snaps¶
type: list
default: install no extra snaps
can be interactive: true
A list of snaps to install. Each snap is represented as a mapping with a required name
and an optional channel
(default is stable
) and classic (default is false
) keys. For example:
autoinstall:
snaps:
- name: etcd
channel: edge
classic: false
debconf-selections¶
type: string
default: no configuration
can be interactive: no
The installer updates the target with debconf set-selection
values. Users need to be familiar with the options of the debconf
package.
packages¶
type: list
default: no packages
can be interactive: no
A list of packages to install into the target system. Specifically, a list of strings to pass to the apt-get install
command. Therefore, this includes things such as task selection (dns-server^
) and installing particular versions of a package (my-package=1-1
).
kernel¶
type: mapping (mutually exclusive), see below
default: default kernel
can be interactive: no
Which kernel gets installed. Either the name of the package or the name of the flavour must be specified.
package¶
type: string
The name of the package, e.g., linux-image-5.13.0-40-generic
.
flavor¶
type: string
The flavor
of the kernel, e.g., generic
or hwe
.
timezone¶
type: string
default: no timezone
can be interactive: no
The timezone to configure on the system. The special value geoip
can be used to query the timezone automatically over the network.
updates¶
type: string (enumeration)
default:
security
can be interactive: no
The type of updates that will be downloaded and installed after the system installation. Supported values are:
security
: download and install updates from the-security
pocket.all
: also download and install updates from the-updates
pocket.
shutdown¶
type: string (enumeration)
default:
reboot
can be interactive: no
Request the system to power off or reboot automatically after the installation has finished. Supported values are:
reboot
poweroff
late-commands¶
type: command list
default: no commands
can be interactive: no
Shell commands to run after the installation has completed successfully and any updates and packages installed, just before the system reboots. The commands are run in the installer environment with the installed system mounted at /target
. You can run curtin in-target -- $shell_command
(with the version of Subiquity
released with 20.04 GA, you need to specify this as curtin in-target --target=/target -- $shell_command
) to run in the target system (similar to how plain in-target
can be used in d-i preseed/late_command
).
error-commands¶
type: command list
default: no commands
can be interactive: no
Shell commands to run after the installation has failed. They are run in the installer environment, and the target system (or as much of it as the installer managed to configure) is mounted at /target
. Logs will be available in /var/log/installer
in the live session.
reporting¶
type: mapping
default:
type: print
(which causes output ontty1
and any configured serial consoles)can be interactive: no
The installer supports reporting progress to a variety of destinations. Note that this section is ignored if there are any interactive sections; it only applies to fully automated installations.
The configuration is similar to that used by curtin. See the Reporting section of the curtin documentation.
Each key in the reporting
mapping in the configuration defines a destination where the type
sub-key is one of:
print
: print progress information ontty1
and any configured serial console. There is no other configuration.rsyslog
: report progress via rsyslog. Thedestination
key specifies where to send output. (The rsyslog reporter does not yet exist.)webhook
: report progress by sending JSON reports to a URL using POST requests. Accepts the same configuration as curtin.none
: do not report progress. Only useful to inhibit the default output.
Reporting examples:
The default configuration is:
autoinstall:
reporting:
builtin:
type: print
Report to rsyslog:
autoinstall:
reporting:
central:
type: rsyslog
destination: "@192.168.0.1"
Suppress the default output:
autoinstall:
reporting:
builtin:
type: none
Report to a curtin-style webhook:
autoinstall:
reporting:
hook:
type: webhook
endpoint: http://example.com/endpoint/path
consumer_key: "ck_value"
consumer_secret: "cs_value"
token_key: "tk_value"
token_secret: "tk_secret"
level: INFO
user-data¶
type: mapping
default:
{}
can be interactive: no
Provide cloud-init user data, which will be merged with the user data the installer produces. If you supply this, you don’t need to supply an identity section (in that case, ensure you can log in to the installed system).