镜像
首先你需要一个ubuntu系统安装镜像文件（下载地址：http://www.ubuntu.com/download），这里使用的是ubuntu-14.04-server-amd64.iso。
挂载ubuntu iso：
mkdir /mnt/ubuntu
sudo mount -t iso9660 ubuntu-14.04-server-amd64.iso /mnt/ubuntu/ -o loop
Note:mount会在重启后失效，如果不想重复执行，可以把mount命令加到/etc/profile中
DHCP服务
安装dhcp server：
sudo apt-get install isc-dhcp-server
配置dhcp server（假设本机ip为192.168.16.1）：
sudo vi /etc/dhcp/dhcpd.conf
添加以下内容:
subnet 192.168.16.0 netmask 255.255.255.0 {
range 192.168.16.200 192.168.16.250;
option routers 192.168.16.1;
option broadcast-address 192.168.16.255;
default-lease-time 600;
max-lease-time 7200;
filename "pxelinux.0";
}
range为分配给dhcp client的地址池首尾地址。
修改记得重启服务：sudo service isc-dhcp-server restart
tftp服务
安装tftp服务:
sudo apt-get install tftpd-hpa
配置tftp服务，添加必须的文件到tftp指定的目录，tftpd-hpa默认根目录为/srv/tftp。
sudo cp -R /mnt/ubuntu/install/netboot/* /srv/tftp/
http服务
web服务采用的是lighttpd程序，你也可以采用apache等。
sudo apt-get install lighttpd
安装好后，默认的根目录为/var/www，你也可以通过修改配置文件来修改默认的根目录，这里我们采用默认的根目录
创建ubuntu链接。
sudo ln -s /mnt/ubuntu /var/www/ubuntu
如果不出意外，可以通过浏览器访问http://192.168.16.1/ubuntu/md5sum.txt
此时已经可以达到网络安装的目的了，但是所有选项还是需要手动在客户机上操作。
下面将通过配置初步达到完全的无人值守安装的效果。
创建新的initrd.gz
此处ubuntu镜像是64位的，如果是32位，amd64改为i386。
cd /srv/tftp/ubuntu-installer/amd64/
cp initrd.gz ~/
cd ~
gunzip initrd.gz
mv initrd initrd.img
mkdir initrd
cd initrd
cpio –i <../initrd.img
vi preseed.cfg
下面假设pxe服务器（本机）ip为192.168.16.1，复制以下内容到 preseed.cfg，可以根据自己的需求修改配置。
#### Contents of the preconfiguration file (for lenny)
### Localization
# Preseeding only locale sets language, country and locale.
d-i debian-installer/locale string en_US
# The values can also be preseeded individually for greater flexibility.
#d-i debian-installer/language string en
#d-i debian-installer/country string NL
#d-i debian-installer/locale string en_GB.UTF-8
# Optionally specify additional locales to be generated.
#d-i localechooser/supported-locales en_US.UTF-8, nl_NL.UTF-8
# Keyboard selection.
# Disable automatic (interactive) keymap detection.
d-i console-setup/ask_detect boolean false
#d-i keyboard-configuration/modelcode string pc105
d-i keyboard-configuration/layoutcode string us
# To select a variant of the selected layout (if you leave this out, the
# basic form of the layout will be used):
#d-i keyboard-configuration/variantcode string dvorak
### Network configuration
# Disable network configuration entirely. This is useful for cdrom
# installations on non-networked devices where the network questions,
# warning and long timeouts are a nuisance.
#d-i netcfg/enable boolean false
# netcfg will choose an interface that has link if possible. This makes it
# skip displaying a list if there is more than one interface.
d-i netcfg/choose_interface select auto
# To pick a particular interface instead:
#d-i netcfg/choose_interface select eth1
# If you have a slow dhcp server and the installer times out waiting for
# it, this might be useful.
#d-i netcfg/dhcp_timeout string 60
# If you prefer to configure the network manually, uncomment this line and
# the static network configuration below.
#d-i netcfg/disable_autoconfig boolean true
# If you want the preconfiguration file to work on systems both with and
# without a dhcp server, uncomment these lines and the static network
# configuration below.
#d-i netcfg/dhcp_failed note
#d-i netcfg/dhcp_options select Configure network manually
# Static network configuration.
d-i netcfg/get_nameservers string 192.168.16.1
#d-i netcfg/get_ipaddress string 192.168.1.42
#d-i netcfg/get_netmask string 255.255.255.0
#d-i netcfg/get_gateway string 192.168.1.1
#d-i netcfg/confirm_static boolean true
# Any hostname and domain names assigned from dhcp take precedence over
# values set here. However, setting the values still prevents the questions
# from being shown, even if values come from dhcp.
d-i netcfg/get_hostname string dyang
d-i netcfg/get_domain string dyang
# Disable that annoying WEP key dialog.
d-i netcfg/wireless_wep string
# The wacky dhcp hostname that some ISPs use as a password of sorts.
#d-i netcfg/dhcp_hostname string radish
# If non-free firmware is needed for the network or other hardware, you can
# configure the installer to always try to load it, without prompting. Or
# change to false to disable asking.
#d-i hw-detect/load_firmware boolean true
### Network console
# Use the following settings if you wish to make use of the network-console
# component for remote installation over SSH. This only makes sense if you
# intend to perform the remainder of the installation manually.
#d-i anna/choose_modules string network-console
#d-i network-console/password password r00tme
#d-i network-console/password-again password r00tme
# Use this instead if you prefer to use key-based authentication
#d-i network-console/authorized_keys_url http://host/authorized_keys
### Mirror settings
# If you select ftp, the mirror/country string does not need to be set.
#d-i mirror/protocol string http
#d-i mirror/country string manual
#d-i mirror/http/hostname string 192.168.16.1
#d-i mirror/http/directory string /ubuntu
#d-i mirror/http/proxy string
# Alternatively: by default, the installer uses CC.archive.ubuntu.com where
# CC is the ISO-3166-2 code for the selected country. You can preseed this
# so that it does so without asking.
d-i mirror/http/mirror select CC.archive.ubuntu.com
# Suite to install.
#d-i mirror/suite string lenny
# Suite to use for loading installer components (optional).
#d-i mirror/udeb/suite string lenny
# Components to use for loading installer components (optional).
#d-i mirror/udeb/components multiselect main, restricted
### Clock and time zone setup
# Controls whether or not the hardware clock is set to UTC.
d-i clock-setup/utc boolean true
# You may set this to any valid setting for $TZ; see the contents of
# /usr/share/zoneinfo/ for valid values.
d-i time/zone string Asia/Shanghai
# Controls whether to use NTP to set the clock during the install
d-i clock-setup/ntp boolean true
# NTP server to use. The default is almost always fine here.
#d-i clock-setup/ntp-server string ntp.example.com
### Partitioning
## Partitioning example
# If the system has free space you can choose to only partition that space.
# This is only honoured if partman-auto/method (below) is not set.
# Alternatives: custom, some_device, some_device_crypto, some_device_lvm.
#d-i partman-auto/init_automatically_partition select biggest_free
# Alternatively, you may specify a disk to partition. If the system has only
# one disk the installer will default to using that, but otherwise the device
# name must be given in traditional, non-devfs format (so e.g. /dev/hda or
# /dev/sda, and not e.g. /dev/discs/disc0/disc).
# For example, to use the first SCSI/SATA hard disk:
#d-i partman-auto/disk string /dev/sda
# In addition, you'll need to specify the method to use.
# The presently available methods are:
# - regular: use the usual partition types for your architecture
# - lvm: use LVM to partition the disk
# - crypto: use LVM within an encrypted partition
d-i partman-auto/method string regular
# If one of the disks that are going to be automatically partitioned
# contains an old LVM configuration, the user will normally receive a
# warning. This can be preseeded away...
d-i partman-lvm/device_remove_lvm boolean true
# The same applies to pre-existing software RAID array:
d-i partman-md/device_remove_md boolean true
# And the same goes for the confirmation to write the lvm partitions. d-i partman-lvm/confirm boolean true
# For LVM partitioning, you can select how much of the volume group to use
# for logical volumes.
d-i partman-auto-lvm/guided_size string max
#d-i partman-auto-lvm/guided_size string 10GB
#d-i partman-auto-lvm/guided_size string 50%
# You can choose one of the three predefined partitioning recipes:
# - atomic: all files in one partition
# - home: separate /home partition
# - multi: separate /home, /usr, /var, and /tmp partitions
d-i partman-auto/choose_recipe select atomic
# Or provide a recipe of your own...
# If you have a way to get a recipe file into the d-i environment, you can
# just point at it.
#d-i partman-auto/expert_recipe_file string /hd-media/recipe
# If not, you can put an entire recipe into the preconfiguration file in one
# (logical) line. This example creates a small /boot partition, suitable
# swap, and uses the rest of the space for the root partition:
#d-i partman-auto/expert_recipe string \
# boot-root :: \
# 40 50 100 ext3 \
# $primary{ } $bootable{ } \
# method{ format } format{ } \
# use_filesystem{ } filesystem{ ext3 } \
# mountpoint{ /boot } \
# . \
# 500 10000 1000000000 ext3 \
# method{ format } format{ } \
# use_filesystem{ } filesystem{ ext3 } \
# mountpoint{ / } \
# . \
# 64 512 300% linux-swap \
# method{ swap } format{ } \
# .
# If you just want to change the default filesystem from ext3 to something
# else, you can do that without providing a full recipe.
#d-i partman/default_filesystem string ext4
# The full recipe format is documented in the file partman-auto-recipe.txt
# included in the 'debian-installer' package or available from D-I source
# repository. This also documents how to specify settings such as file
# system labels, volume group names and which physical devices to include
# in a volume group.
# This makes partman automatically partition without confirmation, provided
# that you told it what to do using one of the methods above.
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
## Partitioning using RAID
# The method should be set to "raid".
#d-i partman-auto/method string raid
# Specify the disks to be partitioned. They will all get the same layout,
# so this will only work if the disks are the same size.
#d-i partman-auto/disk string /dev/sda /dev/sdb
# Next you need to specify the physical partitions that will be used.
#d-i partman-auto/expert_recipe string \
# multiraid :: \
# 1000 5000 4000 raid \
# $primary{ } method{ raid } \
# . \
# 64 512 300% raid \
# method{ raid } \
# . \
# 500 10000 1000000000 raid \
# method{ raid } \
# .
# Last you need to specify how the previously defined partitions will be
# used in the RAID setup. Remember to use the correct partition numbers
# for logical partitions. RAID levels 0, 1, 5, 6 and 10 are supported;
# devices are separated using "#".
# Parameters are:
# <raidtype> <devcount> <sparecount> <fstype> <mountpoint> \
# <devices> <sparedevices>
#d-i partman-auto-raid/recipe string \
# 1 2 0 ext3 / \
# /dev/sda1#/dev/sdb1 \
# . \
# 1 2 0 swap - \
# /dev/sda5#/dev/sdb5 \
# . \
# 0 2 0 ext3 /home \
# /dev/sda6#/dev/sdb6 \
# .
# For additional information see the file partman-auto-raid-recipe.txt
# included in the 'debian-installer' package or available from D-I source
# repository.
# This makes partman automatically partition without confirmation.
d-i partman-md/confirm boolean true
## Controlling how partitions are mounted
# The default is to mount by UUID, but you can also choose "traditional" to
# use traditional device names, or "label" to try filesystem labels before
# falling back to UUIDs.
#d-i partman/mount_style select uuid
d-i live-installer/net-image string http://192.168.16.1/ubuntu/install/filesystem.squashfs
### Base system installation
# Configure APT to not install recommended packages by default. Use of this
# option can result in an incomplete system and should only be used by very
# experienced users.
#d-i base-installer/install-recommends boolean false
# The kernel image (meta) package to be installed; "none" can be used if no
# kernel is to be installed.
d-i base-installer/kernel/image string linux-generic
### Account setup
# Skip creation of a root account (normal user account will be able to
# use sudo). The default is false; preseed this to true if you want to set
# a root password.
#d-i passwd/root-login boolean false
# Alternatively, to skip creation of a normal user account.
#d-i passwd/make-user boolean false
# Root password, either in clear text
#d-i passwd/root-password password r00tme
#d-i passwd/root-password-again password r00tme
# or encrypted using an MD5 hash.
#d-i passwd/root-password-crypted password [MD5 hash]
# To create a normal user account.
d-i passwd/user-fullname string dyang
d-i passwd/username string dyang
# Normal user's password, either in clear text
d-i passwd/user-password password dyang
d-i passwd/user-password-again password dyang
# or encrypted using an MD5 hash.
#d-i passwd/user-password-crypted password [MD5 hash]
# Create the first user with the specified UID instead of the default.
d-i passwd/user-uid string 1010
# The installer will warn about weak passwords. If you are sure you know
# what you're doing and want to override it, uncomment this.
#d-i user-setup/allow-password-weak boolean true
# The user account will be added to some standard initial groups. To
# override that, use this.
#d-i passwd/user-default-groups string audio cdrom video
# Set to true if you want to encrypt the first user's home directory.
d-i user-setup/encrypt-home boolean false
### Apt setup
# You can choose to install restricted and universe software, or to install
# software from the backports repository.
#d-i apt-setup/restricted boolean true
#d-i apt-setup/universe boolean true
#d-i apt-setup/backports boolean true
# Uncomment this if you don't want to use a network mirror.
d-i apt-setup/use_mirror boolean false
# Select which update services to use; define the mirrors to be used.
# Values shown below are the normal defaults.
d-i apt-setup/services-select multiselect security
d-i apt-setup/security_host string 192.168.16.1
d-i apt-setup/security_path string /ubuntu
# Additional repositories, local[0-9] available
#d-i apt-setup/local0/repository string \
# http://local.server/ubuntu lenny main
#d-i apt-setup/local0/comment string local server
# Enable deb-src lines
#d-i apt-setup/local0/source boolean true
# URL to the public key of the local repository; you must provide a key or
# apt will complain about the unauthenticated repository and so the
# sources.list line will be left commented out
#d-i apt-setup/local0/key string http://local.server/key
# By default the installer requires that repositories be authenticated
# using a known gpg key. This setting can be used to disable that
# authentication. Warning: Insecure, not recommended.
d-i debian-installer/allow_unauthenticated boolean true
### Package selection
#tasksel tasksel/first multiselect ubuntu-desktop
#tasksel tasksel/first multiselect lamp-server, print-server
#tasksel tasksel/first multiselect kubuntu-desktop
tasksel tasksel/first multiselect standard
# Individual additional packages to install
d-i pkgsel/include string openssh-server build-essential
# Whether to upgrade packages after debootstrap.
# Allowed values: none, safe-upgrade, full-upgrade
d-i pkgsel/upgrade select none
# Language pack selection
#d-i pkgsel/language-packs multiselect de, en, zh
# Policy for applying updates. May be "none" (no automatic updates),
# "unattended-upgrades" (install security updates automatically), or
# "landscape" (manage system with Landscape).
d-i pkgsel/update-policy select none
# Some versions of the installer can report back on what software you have
# installed, and what software you use. The default is not to report back,
# but sending reports helps the project determine what software is most
# popular and include it on CDs.
#popularity-contest popularity-contest/participate boolean false
# By default, the system's locate database will be updated after the
# installer has finished installing most packages. This may take a while, so
# if you don't want it, you can set this to "false" to turn it off.
#d-i pkgsel/updatedb boolean true
### Boot loader installation
# Grub is the default boot loader (for x86). If you want lilo installed
# instead, uncomment this:
#d-i grub-installer/skip boolean true
# To also skip installing lilo, and install no bootloader, uncomment this
# too:
#d-i lilo-installer/skip boolean true
# With a few exceptions for unusual partitioning setups, GRUB 2 is now the
# default. If you need GRUB Legacy for some particular reason, then
# uncomment this:
#d-i grub-installer/grub2_instead_of_grub_legacy boolean false
# This is fairly safe to set, it makes grub install automatically to the MBR
# if no other operating system is detected on the machine.
d-i grub-installer/only_debian boolean true
# This one makes grub-installer install to the MBR if it also finds some other
# OS, which is less safe as it might not be able to boot that other OS.
#d-i grub-installer/with_other_os boolean true
# Alternatively, if you want to install to a location other than the mbr,
# uncomment and edit these lines:
#d-i grub-installer/only_debian boolean false
#d-i grub-installer/with_other_os boolean false
#d-i grub-installer/bootdev string (hd0,0)
# To install grub to multiple disks:
#d-i grub-installer/bootdev string (hd0,0) (hd1,0) (hd2,0)
# Optional password for grub, either in clear text
#d-i grub-installer/password password r00tme
#d-i grub-installer/password-again password r00tme
# or encrypted using an MD5 hash, see grub-md5-crypt(8).
#d-i grub-installer/password-crypted password [MD5 hash]
# Use the following option to add additional boot parameters for the
# installed system (if supported by the bootloader installer).
# Note: options passed to the installer will be added automatically.
#d-i debian-installer/add-kernel-opts string nousb
### Finishing up the installation
# During installations from serial console, the regular virtual consoles
# (VT1-VT6) are normally disabled in /etc/inittab. Uncomment the next
# line to prevent this.
#d-i finish-install/keep-consoles boolean true
# Avoid that last message about the install being complete.
d-i finish-install/reboot_in_progress note
# This will prevent the installer from ejecting the CD during the reboot,
# which is useful in some situations.
#d-i cdrom-detect/eject boolean false
# This is how to make the installer shutdown when finished, but not
# reboot into the installed system.
#d-i debian-installer/exit/halt boolean true
# This will power off the machine instead of just halting it.
#d-i debian-installer/exit/poweroff boolean true
### X configuration
# X can detect the right driver for some cards, but if you're preseeding,
# you override whatever it chooses. Still, vesa will work most places.
#xserver-xorg xserver-xorg/config/device/driver select vesa
# A caveat with mouse autodetection is that if it fails, X will retry it
# over and over. So if it's preseeded to be done, there is a possibility of
# an infinite loop if the mouse is not autodetected.
#xserver-xorg xserver-xorg/autodetect_mouse boolean true
# Monitor autodetection is recommended.
xserver-xorg xserver-xorg/autodetect_monitor boolean true
# Uncomment if you have an LCD display.
#xserver-xorg xserver-xorg/config/monitor/lcd boolean true
# X has three configuration paths for the monitor. Here's how to preseed
# the "medium" path, which is always available. The "simple" path may not
# be available, and the "advanced" path asks too many questions.
xserver-xorg xserver-xorg/config/monitor/selection-method \
select medium
xserver-xorg xserver-xorg/config/monitor/mode-list \
select 1024x768 @ 60 Hz
### Preseeding other packages
# Depending on what software you choose to install, or if things go wrong
# during the installation process, it's possible that other questions may
# be asked. You can preseed those too, of course. To get a list of every
# possible question that could be asked during an install, do an
# installation, and then run these commands:
# debconf-get-selections --installer > file
# debconf-get-selections >> file
#### Advanced options
### Running custom commands during the installation
# d-i preseeding is inherently not secure. Nothing in the installer checks
# for attempts at buffer overflows or other exploits of the values of a
# preconfiguration file like this one. Only use preconfiguration files from
# trusted locations! To drive that home, and because it's generally useful,
# here's a way to run any shell command you'd like inside the installer,
# automatically.
# This first command is run as early as possible, just after
# preseeding is read.
#d-i preseed/early_command string anna-install some-udeb
# This command is run immediately before the partitioner starts. It may be
# useful to apply dynamic partitioner preseeding that depends on the state
# of the disks (which may not be visible when preseed/early_command runs).
#d-i partman/early_command \
# string debconf-set partman-auto/disk "$(list-devices disk | head -n1)"
# This command is run just before the install finishes, but when there is
# still a usable /target directory. You can chroot to /target and use it
# directly, or use the apt-install and in-target commands to easily install
# packages and run commands in the target system.
#d-i preseed/late_command string apt-install zsh; in-target chsh -s /bin/zsh
上面很多配置就不细说了，可以根据注释说明修改，注意把我的ip修改成你自己的基本问题不大，此处特别讲以下我选择了默认安装的软件：
d-i pkgsel/include string openssh-server build-essential
保存文件后在initerd下执行命令，将在～/下生成新的initrd.gz，然后复制到tftp路径
find . | cpio -o -H newc |gzip -9 >../initrd.gz
sudo cp ../initrd.gz /srv/tftp/ubuntu-installer/amd64/
自动选择Install
此时你已经可以自动配置安装了。
但是还有个问题，就是客户机开机后会显示Install boot menu，仍然需要手工确认Install选项才开始安装。
下面继续修改：
sudo vi /srv/tftp/pxelinux.cfg/default
主要修改其中的timeout项，先确认默认选项已经为Install，只需要设置超时自动确认当前选中项即可，timeout单位为1/10秒。这里我使用的是1秒后自动进入安装。
此修改存在风险，任何接入的PC都可能被重装系统，所以根据需要调整。为0时无限等待手动选择。
# D-I config version 2.0
include ubuntu-installer/amd64/boot-screens/menu.cfg
default ubuntu-installer/amd64/boot-screens/vesamenu.c32
prompt 0
timeout 10