Difference between revisions of "PXE"

From ArchWiki
Jump to: navigation, search
m (pxelinux.0 is no longer available on iso but lpxelinux.0 is (see http://www.syslinux.org/wiki/index.php/Syslinux_5_Changelog))
m (NBD: Use Install and Start links)
 
(44 intermediate revisions by 20 users not shown)
Line 4: Line 4:
 
[[es:PXE]]
 
[[es:PXE]]
 
[[fr:Install PXE]]
 
[[fr:Install PXE]]
[[ru:Install Arch from network via PXE (Русский)]]
+
[[ja:PXE]]
{{Article summary start}}
+
[[ru:Install Arch from network via PXE]]
{{Article summary text|Detailed guide to booting official installation media via PXE.}}
+
[[zh-CN:PXE]]
{{Article summary heading|Related}}
+
{{Related articles start}}
{{Article summary wiki|Network Installation Guide}}
+
{{Related|Diskless system}}
{{Article summary end}}
+
{{Related articles end}}
 
From [[Wikipedia:Preboot Execution Environment]]:
 
From [[Wikipedia:Preboot Execution Environment]]:
 
:''The Preboot eXecution Environment (PXE, also known as Pre-Execution Environment; sometimes pronounced "pixie") is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems.''
 
:''The Preboot eXecution Environment (PXE, also known as Pre-Execution Environment; sometimes pronounced "pixie") is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems.''
  
In this guide, PXE is used to boot the installation media with an appropriate option-rom that supports PXE on the target.
+
In this guide, PXE is used to boot the installation media with an appropriate option-rom that supports PXE on the target. This works well when you already have a server set up.
  
 
== Preparation ==
 
== Preparation ==
  
Download the latest official install media from [https://www.archlinux.org/download/ here].
+
Get the latest official install media from [https://www.archlinux.org/download/ download page].
  
 
Next mount the image:
 
Next mount the image:
Line 27: Line 27:
 
== Server setup ==
 
== Server setup ==
  
You'll need to setup a DHCP, TFTP, and HTTP server to configure networking, load pxelinux/kernel/initramfs, and finally load the root filesystem (respectively).
+
You will need to setup a DHCP, TFTP, and HTTP server to configure networking, load pxelinux/kernel/initramfs, and finally load the root filesystem (respectively).
  
 
=== Network ===
 
=== Network ===
Line 39: Line 39:
 
=== DHCP + TFTP ===
 
=== DHCP + TFTP ===
  
You'll need both a DHCP and TFTP server to configure networking on the install target and to facilitate the transfer of files between the PXE server and client; dnsmasq does both, and is extremely easy to set up.
+
You will need both a DHCP and TFTP server to configure networking on the install target and to facilitate the transfer of files between the PXE server and client; ''dnsmasq'' does both, and is extremely easy to set up.
  
Install {{pkg|dnsmasq}}:
+
[[Install]] the {{pkg|dnsmasq}} package.
  
{{bc|# pacman -S dnsmasq}}
+
Configure ''dnsmasq'':
  
Configure {{pkg|dnsmasq}}:
+
{{hc|# /etc/dnsmasq.conf|2=
 
+
{{hc|# vim /etc/dnsmasq.conf|2=
+
 
port=0
 
port=0
 
interface=eth0
 
interface=eth0
Line 55: Line 53:
 
dhcp-option-force=209,boot/syslinux/archiso.cfg
 
dhcp-option-force=209,boot/syslinux/archiso.cfg
 
dhcp-option-force=210,/arch/
 
dhcp-option-force=210,/arch/
 +
dhcp-option-force=66,192.168.0.1
 
enable-tftp
 
enable-tftp
 
tftp-root=/mnt/archiso}}
 
tftp-root=/mnt/archiso}}
  
Start {{pkg|dnsmasq}}:
+
[[Start]] {{ic|dnsmasq.service}}.
 
+
{{bc|# systemctl start dnsmasq.service}}
+
  
 
=== HTTP ===
 
=== HTTP ===
  
Thanks to recent changes in [[Archiso|archiso]], it is now possible to boot from HTTP (archiso_pxe_http initcpio hook) or NFS (archiso_pxe_nfs initcpio hook); among all alternatives, darkhttpd is by far the most trivial to setup (and the lightest-weight).
+
Thanks to recent changes in [[archiso]], it is now possible to boot from HTTP (archiso_pxe_http initcpio hook) or NFS (archiso_pxe_nfs initcpio hook); among all alternatives, darkhttpd is by far the most trivial to setup (and the lightest-weight).
  
First, install {{pkg|darkhttpd}}:
+
First, [[install]] the {{pkg|darkhttpd}} package.
  
{{bc|# pacman -S darkhttpd}}
+
Then start ''darkhttpd'' using our {{ic|/mnt/archiso}} as the document root:
  
Then start {{pkg|darkhttpd}} using our /mnt/archiso as the document root:
+
{{hc|# darkhttpd /mnt/archiso|
 
+
{{hc|# darkhttpd /mnt/archiso|2=
+
 
darkhttpd/1.8, copyright (c) 2003-2011 Emil Mikulic.
 
darkhttpd/1.8, copyright (c) 2003-2011 Emil Mikulic.
listening on: http://0.0.0.0:80/}}
+
listening on: <nowiki>http://0.0.0.0:80/</nowiki>}}
 +
 
 +
Note that it is important that the server is running on port 80. If you start ''darkhttpd'' without root access it will default to 8080. The client will try to access port 80 and the boot will fail.
  
 
== Installation ==
 
== Installation ==
  
For this portion you'll need to figure out how to tell the client to attempt a PXE boot; in the corner of the screen along with the normal post messages, usually there will be some hint on which key to press to try PXE booting first. On an IBM x3650 ''F12'' brings up a boot menu, the first option of which is ''Network''; on a Dell PE 1950/2950 pressing ''F12'' initiates PXE booting directly.
+
For this portion you will need to figure out how to tell the client to attempt a PXE boot; in the corner of the screen along with the normal post messages, usually there will be some hint on which key to press to try PXE booting first. On an IBM x3650 ''F12'' brings up a boot menu, the first option of which is ''Network''; on a Dell PE 1950/2950 pressing ''F12'' initiates PXE booting directly.
  
 
=== Boot ===
 
=== Boot ===
Line 102: Line 99:
 
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/splash.png to 192.168.0.110</nowiki>}}
 
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/splash.png to 192.168.0.110</nowiki>}}
  
After you load {{ic|pxelinux.0}} and {{ic|archiso.cfg}} via TFTP, you'll (hopefully) be presented with a [[Syslinux|syslinux]] boot menu with several options, two of which are of potential usefulness to us.
+
After you load {{ic|pxelinux.0}} and {{ic|archiso.cfg}} via TFTP, you will (hopefully) be presented with a [[syslinux]] boot menu with several options, two of which are of potential usefulness to us.
  
Select either
+
Select either ''Boot Arch Linux (x86_64) (HTTP)'' or ''Boot Arch Linux (i686) (HTTP)'' depending on your CPU architecture.  
 
+
{{bc|Boot Arch Linux (x86_64) (HTTP)}}
+
 
+
or
+
 
+
{{bc|Boot Arch Linux (i686) (HTTP)}}
+
 
+
depending on your CPU architecture.  
+
  
 
Next the kernel and initramfs (appropriate for the architecture you selected) will be transferred, again via TFTP:
 
Next the kernel and initramfs (appropriate for the architecture you selected) will be transferred, again via TFTP:
Line 128: Line 117:
 
1348347588 192.168.0.110 "GET /arch/any/usr-share.fs.sfs" 200 63693037 "" "curl/7.27.0"}}
 
1348347588 192.168.0.110 "GET /arch/any/usr-share.fs.sfs" 200 63693037 "" "curl/7.27.0"}}
  
After the root filesystem is downloaded via HTTP, you'll eventually end up at a root zsh prompt with that fancy [https://www.archlinux.org/packages/extra/any/grml-zsh-config/ grml config].
+
After the root filesystem is downloaded via HTTP, you will eventually end up at the normal live system root [[zsh]] prompt.
  
 
=== Post-boot ===
 
=== Post-boot ===
  
Unless you want all traffic to be routed through your PXE server (which won't work anyway unless you [[Simple Stateful Firewall#Setting up a NAT gateway|set it up properly]]), you'll want to kill {{pkg|dnsmasq}} and get a new lease on the install target, as appropriate for your network layout.
+
Unless you want all traffic to be routed through your PXE server (which will not work anyway unless you [[Simple stateful firewall#Setting up a NAT gateway|set it up properly]]), you will want to [[stop]] {{ic|dnsmasq.service}} and get a new lease on the install target, as appropriate for your network layout.
  
{{bc|# systemctl stop dnsmasq.service}}
+
You can also kill ''darkhttpd''; the target has already downloaded the root filesystem, so it is no longer needed. While you are at it, you can also unmount the installation image:
 
+
You can also kill {{pkg|darkhttpd}}; the target has already downloaded the root filesystem, so it's no longer needed. While you're at it, you can also unmount the installation image:
+
  
 
{{bc|# umount /mnt/archiso}}
 
{{bc|# umount /mnt/archiso}}
  
At this point you can follow the [[Installation_Guide|official installation guide]].
+
At this point you can follow the [[Installation guide|official installation guide]].
  
 
== Alternate Methods ==
 
== Alternate Methods ==
Line 148: Line 135:
 
=== NFS ===
 
=== NFS ===
  
You will need to set up an [[NFS|NFS server]] with an export at the root of your mounted installation media, which would be {{ic|/mnt/archiso}} if you followed the [[PXE#Preparation|earlier sections]] of this guide.  After setting up the server, add the following line to your {{ic|/etc/exports}} file:
+
You will need to set up an [[NFS|NFS server]] with an export at the root of your mounted installation media, which would be {{ic|/mnt/archiso}} if you followed the [[#Preparation|earlier sections]] of this guide.  After setting up the server, add the following line to your {{ic|/etc/exports}} file:
  
 
{{hc|/etc/exports|/mnt/archiso 192.168.0.0/24(ro,no_subtree_check)}}
 
{{hc|/etc/exports|/mnt/archiso 192.168.0.0/24(ro,no_subtree_check)}}
Line 164: Line 151:
 
=== NBD ===
 
=== NBD ===
  
{{Accuracy|verify}}
+
[[Install]] the {{pkg|nbd}} package and configure it:
{{Expansion}}
+
 
+
Install {{pkg|nbd}} and configure it:
+
  
 
{{hc|# vim /etc/nbd-server/config|2=
 
{{hc|# vim /etc/nbd-server/config|2=
Line 175: Line 159:
 
     exportname = /srv/archlinux-2013.02.01-dual.iso}}
 
     exportname = /srv/archlinux-2013.02.01-dual.iso}}
  
=== Low memory ===
+
[[Start]] {{ic|nbd.service}}.
  
The {{ic|copytoram}} [[mkinitcpio|initramfs]] option can be used to control whether the root filesystem should be copied to ram in its entirety in early-boot.
+
=== Existing PXE Server ===
 +
 
 +
If you have an existing PXE server with a syslinux system setup (e.g. a combination of BIND+DHCPd+TFTPd), you can add the following menu items to your pxelinux.cfg file in order to boot Arch via your preferred method:
 +
 
 +
{{hc|# vim /srv/tftp/arch.menu|2=
 +
LABEL 2
 +
        MENU LABEL Arch Linux x86_64
 +
        LINUX /path/to/extracted/Arch/ISO/arch/boot/x86_64/vmlinuz
 +
        INITRD /path/to/extracted/Arch/ISO/arch/boot/intel_ucode.img,/path/to/extracted/Arch/ISO/arch/boot/x86_64/archiso.img
 +
        APPEND archisobasedir=arch archiso_nfs_srv=${nfsserver}:/path/to/extracted/Arch/ISO/ ip=:::::eth0:dhcp
 +
        SYSAPPEND 3
 +
        TEXT HELP
 +
        Arch Linux 2016.03 x86_64
 +
        ENDTEXT}}
 +
 
 +
Replace x86_64 with i686 to boot the 32-bit variant. You can also replace archiso_nfs_srv with any of the supported methods listed above (HTTP, NBD). Adding the ip= instruction is necessary to instruct the kernel to bring up the network interface before it attempts to mount the installation medium over the network.
 +
 
 +
=== DHCP interface rename bug ===
 +
 
 +
As of November 2015 there is {{Bug|36749}} that causes default [http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ predictable network interface renaming] to fail and then dhcp client to fail because of it. A workaround is to add the kernel boot parameter net.ifnames=0 to disable predictable interface names.
 +
 
 +
=== Low memory systems ===
 +
 
 +
The {{ic|copytoram}} [[initramfs]] option can be used to control whether the root filesystem should be copied to ram in its entirety in early-boot.
  
 
It highly recommended to leave this option alone, and should only be disabled if entirely necessary (systems with less than ~256MB physical memory). Append {{ic|<nowiki>copytoram=n</nowiki>}} to your kernel line if you wish to do so.
 
It highly recommended to leave this option alone, and should only be disabled if entirely necessary (systems with less than ~256MB physical memory). Append {{ic|<nowiki>copytoram=n</nowiki>}} to your kernel line if you wish to do so.
 +
 +
{{note|As this requires loop-mounting squashfs from a mounted remote filesystem, {{ic|<nowiki>copytoram=n</nowiki>}} and {{ic|[[#HTTP|archiso_pxe_http]]}} are mutually exclusive.}}

Latest revision as of 05:00, 14 November 2016

Related articles

From Wikipedia:Preboot Execution Environment:

The Preboot eXecution Environment (PXE, also known as Pre-Execution Environment; sometimes pronounced "pixie") is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems.

In this guide, PXE is used to boot the installation media with an appropriate option-rom that supports PXE on the target. This works well when you already have a server set up.

Preparation

Get the latest official install media from download page.

Next mount the image:

# mkdir -p /mnt/archiso
# mount -o loop,ro archlinux-2013.11.01-dual.iso /mnt/archiso

Server setup

You will need to setup a DHCP, TFTP, and HTTP server to configure networking, load pxelinux/kernel/initramfs, and finally load the root filesystem (respectively).

Network

Bring up your wired NIC, and assign it an address appropriately.

# ip link set eth0 up
# ip addr add 192.168.0.1/24 dev eth0

DHCP + TFTP

You will need both a DHCP and TFTP server to configure networking on the install target and to facilitate the transfer of files between the PXE server and client; dnsmasq does both, and is extremely easy to set up.

Install the dnsmasq package.

Configure dnsmasq:

# /etc/dnsmasq.conf
port=0
interface=eth0
bind-interfaces
dhcp-range=192.168.0.50,192.168.0.150,12h
dhcp-boot=/arch/boot/syslinux/lpxelinux.0
dhcp-option-force=209,boot/syslinux/archiso.cfg
dhcp-option-force=210,/arch/
dhcp-option-force=66,192.168.0.1
enable-tftp
tftp-root=/mnt/archiso

Start dnsmasq.service.

HTTP

Thanks to recent changes in archiso, it is now possible to boot from HTTP (archiso_pxe_http initcpio hook) or NFS (archiso_pxe_nfs initcpio hook); among all alternatives, darkhttpd is by far the most trivial to setup (and the lightest-weight).

First, install the darkhttpd package.

Then start darkhttpd using our /mnt/archiso as the document root:

# darkhttpd /mnt/archiso
darkhttpd/1.8, copyright (c) 2003-2011 Emil Mikulic.
listening on: http://0.0.0.0:80/

Note that it is important that the server is running on port 80. If you start darkhttpd without root access it will default to 8080. The client will try to access port 80 and the boot will fail.

Installation

For this portion you will need to figure out how to tell the client to attempt a PXE boot; in the corner of the screen along with the normal post messages, usually there will be some hint on which key to press to try PXE booting first. On an IBM x3650 F12 brings up a boot menu, the first option of which is Network; on a Dell PE 1950/2950 pressing F12 initiates PXE booting directly.

Boot

Looking at journald on the PXE server will provide some additional insight to what exactly is going on during the early stages of the PXE boot process:

# journalctl -u dnsmasq -f
dnsmasq-dhcp[2544]: DHCPDISCOVER(eth1) 00:1a:64:6a:a2:4d 
dnsmasq-dhcp[2544]: DHCPOFFER(eth1) 192.168.0.110 00:1a:64:6a:a2:4d 
dnsmasq-dhcp[2544]: DHCPREQUEST(eth1) 192.168.0.110 00:1a:64:6a:a2:4d 
dnsmasq-dhcp[2544]: DHCPACK(eth1) 192.168.0.110 00:1a:64:6a:a2:4d 
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/pxelinux.0 to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/whichsys.c32 to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso_pxe_choose.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/ifcpu64.c32 to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso_pxe_both_inc.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso_head.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso_pxe32.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso_pxe64.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/archiso_tail.cfg to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/vesamenu.c32 to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/syslinux/splash.png to 192.168.0.110

After you load pxelinux.0 and archiso.cfg via TFTP, you will (hopefully) be presented with a syslinux boot menu with several options, two of which are of potential usefulness to us.

Select either Boot Arch Linux (x86_64) (HTTP) or Boot Arch Linux (i686) (HTTP) depending on your CPU architecture.

Next the kernel and initramfs (appropriate for the architecture you selected) will be transferred, again via TFTP:

dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/x86_64/vmlinuz to 192.168.0.110
dnsmasq-tftp[2544]: sent /mnt/archiso/arch/boot/x86_64/archiso.img to 192.168.0.110

If all goes well, you should then see activity on darkhttpd coming from the PXE-target; at this point the kernel would be loaded on the PXE-target, and in init:

1348347586 192.168.0.110 "GET /arch/aitab" 200 678 "" "curl/7.27.0"
1348347587 192.168.0.110 "GET /arch/x86_64/root-image.fs.sfs" 200 107860206 "" "curl/7.27.0"
1348347588 192.168.0.110 "GET /arch/x86_64/usr-lib-modules.fs.sfs" 200 36819181 "" "curl/7.27.0"
1348347588 192.168.0.110 "GET /arch/any/usr-share.fs.sfs" 200 63693037 "" "curl/7.27.0"

After the root filesystem is downloaded via HTTP, you will eventually end up at the normal live system root zsh prompt.

Post-boot

Unless you want all traffic to be routed through your PXE server (which will not work anyway unless you set it up properly), you will want to stop dnsmasq.service and get a new lease on the install target, as appropriate for your network layout.

You can also kill darkhttpd; the target has already downloaded the root filesystem, so it is no longer needed. While you are at it, you can also unmount the installation image:

# umount /mnt/archiso

At this point you can follow the official installation guide.

Alternate Methods

As implied in the syslinux menu, there are several other alternatives:

NFS

You will need to set up an NFS server with an export at the root of your mounted installation media, which would be /mnt/archiso if you followed the earlier sections of this guide. After setting up the server, add the following line to your /etc/exports file:

/etc/exports
/mnt/archiso 192.168.0.0/24(ro,no_subtree_check)

If the server was already running, re-export the filesystems with exportfs -r -a -v.

The default settings in the installer expect to find the NFS at /run/archiso/bootmnt, so you will need to edit the boot options. To do this, press Tab on the appropriate boot menu choice and edit the archiso_nfs_srv option accordingly:

archiso_nfs_srv=${pxeserver}:/mnt/archiso

Alternatively, you can use /run/archiso/bootmnt for the entire process.

After the kernel loads, the Arch bootstrap image will copy the root filesystem via NFS to the booting host. This can take a little while. Once this completes, you should have a running system.

NBD

Install the nbd package and configure it:

# vim /etc/nbd-server/config
[generic]
[archiso]
    readonly = true
    exportname = /srv/archlinux-2013.02.01-dual.iso

Start nbd.service.

Existing PXE Server

If you have an existing PXE server with a syslinux system setup (e.g. a combination of BIND+DHCPd+TFTPd), you can add the following menu items to your pxelinux.cfg file in order to boot Arch via your preferred method:

# vim /srv/tftp/arch.menu
LABEL 2
        MENU LABEL Arch Linux x86_64
        LINUX /path/to/extracted/Arch/ISO/arch/boot/x86_64/vmlinuz
        INITRD /path/to/extracted/Arch/ISO/arch/boot/intel_ucode.img,/path/to/extracted/Arch/ISO/arch/boot/x86_64/archiso.img
        APPEND archisobasedir=arch archiso_nfs_srv=${nfsserver}:/path/to/extracted/Arch/ISO/ ip=:::::eth0:dhcp
        SYSAPPEND 3
        TEXT HELP
        Arch Linux 2016.03 x86_64
        ENDTEXT

Replace x86_64 with i686 to boot the 32-bit variant. You can also replace archiso_nfs_srv with any of the supported methods listed above (HTTP, NBD). Adding the ip= instruction is necessary to instruct the kernel to bring up the network interface before it attempts to mount the installation medium over the network.

DHCP interface rename bug

As of November 2015 there is FS#36749 that causes default predictable network interface renaming to fail and then dhcp client to fail because of it. A workaround is to add the kernel boot parameter net.ifnames=0 to disable predictable interface names.

Low memory systems

The copytoram initramfs option can be used to control whether the root filesystem should be copied to ram in its entirety in early-boot.

It highly recommended to leave this option alone, and should only be disabled if entirely necessary (systems with less than ~256MB physical memory). Append copytoram=n to your kernel line if you wish to do so.

Note: As this requires loop-mounting squashfs from a mounted remote filesystem, copytoram=n and archiso_pxe_http are mutually exclusive.