.\"     $OpenBSD: autoinstall.8,v 1.23 2021/07/18 11:08:34 kn Exp $
.\"
.\" Copyright (c) 2013 Robert Peichaer <rpe@openbsd.org>
.\"
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.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.Dd $Mdocdate: July 18 2021 $
.Dt AUTOINSTALL 8
.Os
.Sh NAME
.Nm autoinstall
.Nd unattended OpenBSD installation and upgrade
.Sh DESCRIPTION
.Nm
allows unattended installation or upgrade of
.Ox
by automatically responding to installer questions with
answers from a response file.
.Nm
uses DHCP to discover the location of the response
file and HTTP to fetch the file.
If that fails, the installer asks for the location which can either be
a URL or a local path.
.Pp
To start unattended installation or upgrade choose '(A)utoinstall' at the
install prompt.
If there is only one network interface, the installer fetches the response
file via that interface.
If there is more than one network interface, a selection is presented
and the installer fetches the response file via the selected interface.
.Pp
If the machine is netbooted, the
.Nm
feature is invoked if the user does not intervene within
a short time.
It behaves as if the user selected '(A)utoinstall', but
always fetches the response file via the netboot interface.
.Pp
If either
.Pa /auto_install.conf
or
.Pa /auto_upgrade.conf
is found on
.Pa bsd.rd Ns 's
built-in RAM disk,
.Nm
behaves as if the machine is netbooted, but uses the local response file.
In case both files exist,
.Pa /auto_install.conf
takes precedence.
.Pp
.Nm
uses HTTP to fetch one of the files
.Pa install.conf ,
.Ar MAC_address Ns - Ns Pa install.conf
or
.Ar hostname Ns - Ns Pa install.conf
for install answers, or one of
.Pa upgrade.conf ,
.Ar MAC_address Ns - Ns Pa upgrade.conf
or
.Ar hostname Ns - Ns Pa upgrade.conf
for upgrade answers.
.Pp
The URL used to fetch the file is constructed from
.Xr dhcp-options 5
statements extracted from the DHCP lease file.
.Ic next-server
specifies the
.Ar server .
.Ic filename
specifies the
.Ar filename .
The statement
.Ic option host-name
specifies the
.Ar hostname
which is also used as the default hostname during installation.
.Pp
If
.Ar filename
is
.Cm auto_install ,
then the URLs tried are, in order:
.Sm off
.Bd -unfilled -offset indent
.No http:// Ar server No / Ar MAC_address No -install.conf
.No http:// Ar server No / Ar hostname No -install.conf
.No http:// Ar server No /install.conf
.Ed
.Sm on
.Pp
where
.Ar MAC_address
is a string of six hex octets separated by colons
representing the MAC
address of the interface being used to fetch the files.
.Pp
If
.Ar filename
is
.Cm auto_upgrade ,
the URLs tried are, in order:
.Sm off
.Bd -unfilled -offset indent
.No http:// Ar server No / Ar MAC_address No -upgrade.conf
.No http:// Ar server No / Ar hostname No -upgrade.conf
.No http:// Ar server No /upgrade.conf
.Ed
.Sm on
.Pp
On architectures where the
.Ic filename
statement is used to provide the name of the file to netboot
it is necessary to create symbolic links called
.Pa auto_install
and
.Pa auto_upgrade
that point to the expected boot program
and to change the value of the
.Ic filename
statement in the
.Xr dhcpd.conf 5
file to be
.Cm auto_install
or
.Cm auto_upgrade .
.Pp
To use a subdirectory as response file location on the HTTP server, the same
directory structure containing the symbolic links has to exist in the tftproot
directory.
The value of
.Ic filename
has to be the full path to these symbolic links, and the HTTP and TFTP servers
must be on the same machine.
.Pp
The response file is a line-oriented ASCII text file.
The format of each line is:
.Pp
.D1 Ar question No = Ar answer
.Pp
.Ar question
is an installer question (not including the question mark) or a non-ambiguous
part of it, consisting of whitespace separated words.
.Ar answer
is the answer to the question.
Passwords may be in plaintext, encrypted with
.Xr encrypt 1 ,
or set to
.Ql *************
(13 '*'s) to disable password logins, only permitting alternative access methods
(for example,
.Xr ssh 1
keys).
.Pp
If
.Nm
does not find an answer in the response file, the default answer as
provided by the installer is used.
.Pp
The response file may contain answers to the following questions, which are
only available during unattended installation to provide additional installer
features:
.Bl -tag -width Ds
.It Public ssh key for root account = Ar ssh key
.Ar ssh key
is stored in
.Pa /root/.ssh/authorized_keys .
.It Public ssh key for user puffy = Ar ssh key
.Ar ssh key
is stored in
.Pa ~puffy/.ssh/authorized_keys .
.It URL to autopartitioning template for disklabel = Ar url
A template file for
.Xr disklabel 8
autopartitioning is fetched from
.Ar url
allowing a custom partition layout for the root disk.
.El
.Sh FILES
.Bl -tag -width "/etc/dhcpd.confXXX" -compact
.It Pa /etc/dhcpd.conf
.Xr dhcpd 8
configuration file
.It Pa install.conf
response file for unattended installation
.It Pa upgrade.conf
response file for unattended upgrade
.El
.Sh EXAMPLES
A typical
.Pa install.conf
file will look something like this:
.Bd -literal -offset indent
System hostname = server1
Password for root = $2b$14$Z4xRMg8vDpgYH...GVot3ySoj8yby
Change the default console to com0 = yes
Which speed should com0 use = 19200
Setup a user = puffy
Password for user = *************
Public ssh key for user = ssh-ed25519 AAAAC3NzaC1...g3Aqre puffy@ai
What timezone are you in = Europe/Stockholm
Location of sets = http
HTTP Server = cdn.openbsd.org
.Ed
.Pp
The same file could be used for upgrades by creating a symbolic link called
.Pa upgrade.conf
that points to
.Pa install.conf .
The upgrade process will only use the answers it needs.
.Pp
And an example
.Xr dhcpd.conf 5
.Ic host
declaration:
.Bd -literal -offset indent
host foo {
  hardware ethernet 00:50:60:49:8b:84;
  fixed-address 192.168.2.180;
  filename "auto_install";
  option host-name "foo";
}
.Ed
.Sh SEE ALSO
.Xr dhcp-options 5 ,
.Xr dhcpd.conf 5 ,
.Xr diskless 8
.Sh HISTORY
The
.Nm
feature first appeared in
.Ox 5.5 .
.Sh AUTHORS
.An Robert Peichaer Aq Mt rpe@openbsd.org