This preseed file automates the installation of Ubuntu Server 12.04. Replace the values bracketed by less than/greater than symbols with values specific to your own environment.

ubuntu-1204-server-preseed

# Ubuntu Server automated installation

d-i debian-installer/locale string en_US
d-i console-setup/ask_detect boolean false
d-i keyboard-configuration/layoutcode string us
d-i netcfg/choose_interface select eth0
d-i netcfg/get_hostname string unassigned-hostname
d-i netcfg/get_domain string unassigned-domain
d-i netcfg/wireless_wep string
d-i mirror/country string manual
d-i mirror/http/hostname string <mirror.domain.com>
d-i mirror/http/directory string <URL on host>
d-i mirror/http/proxy string http://<apt-cacher-ng.domain.com>:3142
d-i clock-setup/utc boolean true
d-i time/zone string <US/Mountain>
d-i clock-setup/ntp boolean true
d-i clock-setup/ntp-server string 0.us.pool.ntp.org
d-i partman-auto/method string lvm
d-i partman-lvm/device_remove_lvm boolean true
d-i partman-lvm/device_remove_lvm_span boolean true
d-i partman-auto/purge_lvm_from_device boolean true
d-i partman-lvm/confirm boolean true
d-i partman-lvm/confirm_nooverwrite boolean true
d-i partman-auto/choose_recipe select atomic
d-i partman-auto-lvm/guided_size string max
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true
d-i partman-auto/confirm boolean true
d-i passwd/user-fullname string installer
d-i passwd/username string installer
d-i passwd/user-password password r00tme
d-i passwd/user-password-again password r00tme
d-i user-setup/allow-password-weak boolean true
d-i user-setup/encrypt-home boolean false
d-i pkgsel/include string openssh-server update-motd
tasksel tasksel/first multiselect server, openssh-server
d-i pkgsel/update-policy select none
d-i grub-installer/only_debian boolean true
d-i grub-installer/with_other_os boolean true
d-i preseed/late_command string \
wget http://<host.domain.com>/ps/sources.list -O /target/etc/apt/sources.list; wget http://<host.domain.com>/ps/01proxy -O /target/etc/apt/apt.conf.d/01proxy; wget http://<host.domain.com>/ps/postinstall.sh -O /target/var/local/postinstall.sh; chmod a+x /target/var/local/postinstall.sh
d-i finish-install/reboot_in_progress note