---
name: "autoinstall"
section: "8"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/autoinstall"
---

# autoinstall(8)

unattended OpenBSD installation and upgrade

## NAME

**autoinstall** – unattended OpenBSD installation and upgrade

## DESCRIPTION

**autoinstall** allows unattended installation or upgrade of OpenBSD by automatically responding to installer questions with answers from a response file. **autoinstall** 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.

See [install.site(5)](/install.site/5.md) for how to provide custom configuration.

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.

If the machine is netbooted, the **autoinstall** 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.

If either */auto\_install.conf* or */auto\_upgrade.conf* is found on *bsd.rd*'s built-in RAM disk, **autoinstall** behaves as if the machine is netbooted, but uses the local response file. In case both files exist, */auto\_install.conf* takes precedence.

**autoinstall** uses HTTP to fetch one of the files *install.conf*, *MAC\_address*-*install.conf* or *hostname*-*install.conf* for install answers, or one of *upgrade.conf*, *MAC\_address*-*upgrade.conf* or *hostname*-*upgrade.conf* for upgrade answers.

The URL used to fetch the file is constructed from [dhcp-options(5)](/dhcp-options/5.md) statements extracted from the DHCP lease file. **next-server** specifies the *server*. **filename** specifies the *filename*. The statement **option** **host-name** specifies the *hostname* which is also used as the default hostname during installation.

If *filename* is **auto\_install**, then the URLs tried are, in order:

```
http://server/MAC_address-install.conf
http://server/hostname-install.conf
http://server/install.conf
```

where *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.

If *filename* is **auto\_upgrade**, the URLs tried are, in order:

```
http://server/MAC_address-upgrade.conf
http://server/hostname-upgrade.conf
http://server/upgrade.conf
```

On architectures where the **filename** statement is used to provide the name of the file to netboot it is necessary to create symbolic links called *auto\_install* and *auto\_upgrade* that point to the expected boot program and to change the value of the **filename** statement in the [dhcpd.conf(5)](/dhcpd.conf/5.md) file to be **auto\_install** or **auto\_upgrade**.

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 **filename** has to be the full path to these symbolic links, and the HTTP and TFTP servers must be on the same machine.

The response file is a line-oriented ASCII text file. The format of each line is:

*question* = *answer*

*question* is an installer question (not including the question mark) or a non-ambiguous part of it, consisting of whitespace separated words. *answer* is the answer to the question. Passwords may be in plaintext, encrypted with [encrypt(1)](/encrypt/1.md), or set to ‘\*\*\*\*\*\*\*\*\*\*\*\*\*’ (13 '\*'s) to disable password logins, only permitting alternative access methods (for example, [ssh(1)](/ssh/1.md) keys).

If **autoinstall** does not find an answer in the response file, the default answer as provided by the installer is used.

The response file may contain answers to the following questions, which are only available during unattended installation to provide additional installer features:

- Public ssh key for root account = *ssh* *key*

  *ssh* *key* is stored in */root/.ssh/authorized\_keys*.

- Public ssh key for user puffy = *ssh* *key*

  *ssh* *key* is stored in *~puffy/.ssh/authorized\_keys*.

- URL to autopartitioning template for disklabel = *url*

  A template file for [disklabel(8)](/disklabel/8.md) autopartitioning is fetched from *url* allowing a custom partition layout for the root disk.

## FILES

- */etc/dhcpd.conf*

  [dhcpd(8)](/dhcpd/8.md) configuration file

- *install.conf*

  response file for unattended installation

- *upgrade.conf*

  response file for unattended upgrade

## EXAMPLES

A typical *install.conf* file will look something like this:

```
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
```

The same file could be used for upgrades by creating a symbolic link called *upgrade.conf* that points to *install.conf*. The upgrade process will only use the answers it needs.

And an example [dhcpd.conf(5)](/dhcpd.conf/5.md) **host** declaration:

```
host foo {
  hardware ethernet 00:50:60:49:8b:84;
  fixed-address 192.168.2.180;
  filename "auto_install";
  option host-name "foo";
}
```

## SEE ALSO

[dhcp-options(5)](/dhcp-options/5.md), [dhcpd.conf(5)](/dhcpd.conf/5.md), [install.site(5)](/install.site/5.md), [diskless(8)](/diskless/8.md)

## HISTORY

The **autoinstall** feature first appeared in OpenBSD 5.5.

## AUTHORS

Robert Peichaer ⟨*rpe@openbsd.org*⟩