INDEX
-----

* Boot parameters (initramfs stage)
  * hooks/archiso
  * hooks/archiso_pxe_common
  * hooks/archiso_pxe_nbd
  * hooks/archiso_pxe_http
  * hooks/archiso_pxe_nfs
  * hooks/archiso_loop_mnt
* Transfer ISO file to target medium (configs/releng)
  * To -> CD / DVD / BD
  * To -> USB-key / SD / HDD / SSD
    * PC-BIOS (MBR)
    * PC-BIOS (ISOHYBRID-MBR)
    * PC-EFI (GPT) [x86_64 only]
* Alternative boot methods (configs/releng)
  * ISO in loopback mode
  * ISO in memdisk mode
  * Network booting (PXE) [first stage]
    * DHCP + TFTP
    * DHCP + HTTP
    * HTTP/NFS/NBD [second stage]
* Build requirements
* Image types generated by mkarchiso.
* File format for aitab.
* Why the /isolinux and /arch/boot/syslinux directories?
* Know issues
* Building the most basic Arch Linux live media. (configs/baseline)
* Building official Arch Linux live media. (configs/releng)



*** Boot parameters (initramfs stage)

** hooks/archiso

* archisolabel=     Set the filesystem label where archiso files reside.
                    Default: (unset)
* archisodevice=    Set the device node where archiso medium is located.
                    Default: "/dev/disk/by-label/${archisolabel}"
* archisobasedir=   Set the base directory where all files reside.
                    Default: "arch"
* aitab=            Set the path for "aitab" file.
                    Default: ${archisobasedir}/aitab
* copytoram=        If set to "y" or just "copytoram" without arguments,
                    all SquashFS are copied to "RAM".
                    Default: (unset)
* checksum=         If set to "y" or just "checksum" without arguments,
                    performs a self-test of all files inside ${install_dir},
                    and continue booting if ok.
                    Default: (unset)
* cow_label=        Set the filesystem label where COW (dm-snapshot)
                    files must be stored.
                    Default: (unset)
* cow_device=       Set the device node where COW (dm-snapshot) files
                    must be stored.
                    Default: (unset) or "/dev/disk/by-label/${cow_label}"
* cow_directory=    Set a directory inside ${cow_device}.
                    Default: "/persistent_${archisolabel}/${arch}"
* cow_persistent=   Set if snapshots are persistent "P" or non-persistent "N".
                    Default: "N" (if no ${cow_device} is used) otherwise "P".
* cowspace_size=    Set the size of tmpfs /cowspace. This space is used for
                    Copy-On-Write files of dm-snapshot.
                    Size is in bytes (suffix with "k", "m" and "g") or
                    in percentage of available RAM.
                    Default: "75%"
* copytoram_size=   Set the size of tmpfs. This space is used for
                    copy of all SquashFS images used, if copytoram=y.
                    Size is in bytes (suffix with "k", "m" and "g") or
                    in percentage of available RAM.
                    Default: "75%"
* dm_snap_prefix=   Set a prefix for device-mapper snapshot node names.
                    Default: "arch"
* arch=             Force an architecture type (i686 | x86_64).
                    Do not set it for normal operations.
                    Useful for running a 64 bit kernel / 32 bit userspace.
                    Default: (architecture of running kernel)


** hooks/archiso_pxe_common

* ip=               This parameter is setup automatically by PXELINUX
                    when option "IPAPPEND" is set to 1 or 2 in config.
                    ip=<client-ip>:<boot-server-ip>:<gw-ip>:<netmask>
                    Default: (set via PXE server)
* BOOTIF=           This parameter is setup automatically by PXELINUX
                    when option "IPAPPEND" is set to 2 or 3 in config.
                    BOOTIF=<hardware-address-of-boot-interface>
                    Default: (set via PXELINUX)
* copy_resolvconf=  Copy /etc/resolv.conf from initramfs to live-enviroment.
                    Set to "n" to skip them.
                    Default: "y"


** hooks/archiso_pxe_nbd

* archiso_nbd_name= Set NBD export name used by the server.
                    Default: archiso
* archiso_nbd_srv=  Set an IP address where NBD reside.
                    If ${pxeserver} is used, PXE IP will be used.
                    Default: (unset)


** hooks/archiso_pxe_http

* archiso_http_srv= Set an HTTP URL (must end with /) where ${archisobasedir}
                    is found with all *.sfs files.
                    In the IP/domain part if ${pxeserver} is used, use PXE IP.
                    Default: (unset)
* archiso_http_spc= Set the size of tmpfs where *.sfs files are downloaded.
                    Default: "75%"


** hooks/archiso_pxe_nfs

* archiso_nfs_srv=  Set the NFS-IP:/path of the server
                    In the IP part if ${pxeserver} is used, PXE IP will be used.
                    Default: (unset)
* archiso_nfs_opt=  Set NFS mount options separated by comma.
                    Default: (unset, see below)
                    These are the implicit options:
                      port            = as given by server portmap daemon
                      rsize           = 1024
                      wsize           = 1024
                      timeo           = 7
                      retrans         = 3
                      acregmin        = 3
                      acregmax        = 60
                      acdirmin        = 30
                      acdirmax        = 60
                      flags           = hard, nointr, noposix, cto, ac


** hooks/archiso_loop_mnt

* img_label=        Set the filesystem label where archiso-image.iso.
                    Default: (unset)
* img_dev=          Device where archiso-image.iso reside.
                    Default: (unset) or "/dev/disk/by-label/${img_label}"
* img_loop=         Full path where archiso-image.iso is located on ${img_dev}
                    Default: (unset)



*** Transfer ISO image to target medium (configs/releng)

ISO images names consist of: archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso

Where:
    <YYYY> Year
    <MM> Month
    <DD> Day
    <ARCH> i686 | x86_64 | dual(*)

(*) "dual" includes both i686 and x86_64 architectures.


** To -> CD / DVD / BD

Note: All ISO images are booteable on a PC-BIOS via "El Torito" in no-emulation mode,
      All x86_64 ISO images are booteable on a PC-EFI via "El Torito" in no-emulation mode.

Nomeclature:
    <B> scsibus number
    <T> target number
    <L> lun number
    (Note: see cdrecord -scanbus, for these numbers)


1) Write it directly using your favorite recording program.
# cdrecord dev=<B>,<T>,<L> -dao archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso


** To -> USB Flash Drive (USB-key) / Memory card (SD) /
         Hard-Disk Drive (HDD) / Solid-State Drive (SSD)

Note: These steps are the general workflow, you can skip some of them,
      using another filesystem if your bootloader supports it,
      installing to another directory than "arch/" or using more than
      one partition. Just ensure that main boot params options
      (archisolabel= and archisobasedir=) are set correctly according to your setup.

Nomeclature:
<DEV-TARGET>:   Device node of the drive where ISO contents should be copied
                (example: /dev/sdx)
<DEV-TARGET-N>: Device node of the partition on <DEV-TARGET>
                (example: /dev/sdx1)
<MNT-TARGET-N>: Mount point path where <DEV-TARGET-N> is mounted
                (example: /mnt/sdx/1)
<ISO-SOURCE>:   Path to the ISO file archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso
                (example: ~/archlinux-2012.07.22-x86_64.iso)
<FS-LABEL>:     Represents the filesystem label of the <ISO-SOURCE>
                (example: ARCH_201207 [for all ~/archlinux-2012.07.*.iso])


* PC-BIOS (MBR):

Note: Using here a MBR partition mode as example, but GPT should also works
      if machine firmware is not broken.
      Just ensure that partition is set with attribute "2: legacy BIOS bootable"
      and use gptmbr.bin instead of mbr.bin for syslinux.

1) Create one partition entry in MBR (of type "b" for FAT32 or "83" for EXTFS)
   and mark it as "active" (bootable).
# fdisk <DEV-TARGET>

2) Create a FAT32 or EXTFS filesystem on such partition and setup a label.
# mkfs.vfat -F 32 -n <FS-LABEL> <DEV-TARGET-N>
# mkfs.ext4 -L <FS-LABEL> <DEV-TARGET-N>

3) Mount target filesystem.
# mount <DEV-TARGET-N> <MNT-TARGET-N>

4) Extract ISO image on target filesystem.
# bsdtar -x --exclude=isolinux/ --exclude=EFI/ --exclude=loader/ -f <ISO-SOURCE> -C <MNT-TARGET-N>

5) Install syslinux bootloader on target filesystem. (See know issue (2) if using FAT)
# extlinux -i <MNT-TARGET-N>/arch/boot/syslinux

6) Unmount target filesystem.
# umount <MNT-TARGET-N>

7) Install syslinux MBR boot code on target drive.
# dd bs=440 count=1 conv=notrunc if=/usr/lib/syslinux/mbr.bin of=<DEV-TARGET>


* PC-BIOS (ISOHYBRID-MBR):

Note: This method is the most easily, quick and dirty, but is the most limited
      if you want to use your target medium for other purposes.

1) Dump ISO file to target medium.
# dd if=<ISO-SOURCE> of=<DEV-TARGET>


* PC-EFI (GPT) [x86_64 only]

Note: Using here a GPT partition mode as example, but MBR should also works
      if machine firmware is not broken.

1) Create one partition entry in GPT (of type "ef00")
# gdisk <DEV-TARGET>

2) Create a FAT32 filesystem on such partition and setup a label.
# mkfs.vfat -F 32 -n <FS-LABEL> <DEV-TARGET-N>

3) Mount target filesystem.
# mount <DEV-TARGET-N> <MNT-TARGET-N>

4) Extract ISO image on target filesystem.
# bsdtar -x --exclude=isolinux/ --exclude=EFI/archiso/ --exclude=arch/boot/syslinux/ -f <ISO-SOURCE> -C <MNT-TARGET-N>

5) Unmount target filesystem.
# umount <MNT-TARGET-N>



*** Alternative boot methods (configs/releng)

** ISO in loopback mode.

Note: Described method is for using with GRUB2.
      GRUB2 is installed on target media and archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso
      is at path <TARGET-PATH> on disk <D> and partition <P>,
      where filesystem is labeled as <TARGET-FS-LABEL>.

menuentry "Arch Linux (x86_64)" {
    set isofile="/<TARGET-PATH>/archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso"
    loopback loop (hd<D>,<P>)$isofile
    linux (loop)/arch/boot/x86_64/vmlinuz archisolabel=<FS-LABEL> img_label=<TARGET-FS-LABEL> img_loop=$isofile
    initrd (loop)/arch/boot/x86_64/archiso.img
}

menuentry "Arch Linux (i686)" {
    set isofile="/<TARGET-PATH>/archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso"
    loopback loop (hd<D>,<P>)$isofile
    linux (loop)/arch/boot/i686/vmlinuz archisolabel=<FS-LABEL> img_label=<TARGET-FS-LABEL> img_loop=$isofile
    initrd (loop)/arch/boot/i686/archiso.img
}


** ISO in memdisk mode.

Note: Described method is for using with SYSLINUX. Anyway MEMDISK from SYSLINUX can work
      with other bootloaders.
      SYSLINUX is installed on target media and archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso
      is at path <TARGET-PATH>.
      On 32-bit systems, is needed to pass vmalloc=nnM to the kernel, where nn is the size
      of the ISO image plus 64 MiB (or 128 MiB).


LABEL arch_x64
   LINUX memdisk
   INITRD /<TARGET-PATH>/archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso
   APPEND iso

LABEL arch_x32
   LINUX memdisk
   INITRD /<TARGET-PATH>/archlinux-<YYYY>.<MM>.<DD>-<ARCH>.iso
   APPEND iso


** Network booting (PXE).

All ISOs are ready to act as PXE server, some manual steps are needed
to setup the desired PXE boot mode.
Alternatively it is possible to use an existing PXE server following the same logic.
Note: Setup network first, adjust IP adresses, and respect all slashes "/".

First stage is for loading kernel and initramfs via PXE, two methods described here:

* DHCP + TFTP

Note: All NIC firmwares should support this.

# dnsmasq --port=0 \
          --enable-tftp \
          --tftp-root=/run/archiso/bootmnt \
          --dhcp-range=192.168.0.2,192.168.0.254,86400 \
          --dhcp-boot=/arch/boot/syslinux/gpxelinux.0 \
          --dhcp-option-force=209,boot/syslinux/archiso.cfg \
          --dhcp-option-force=210,/arch/

* DHCP + HTTP

Note: Not all NIC firmware supports HTTP and DNS (if domain name is used).
      At least this works with iPXE and gPXE.

# dnsmasq --port=0 \
          --dhcp-range=192.168.0.2,192.168.0.254,86400 \
          --dhcp-boot=http://192.168.0.7/arch/boot/syslinux/gpxelinux.0 \
          --dhcp-option-force=209,boot/syslinux/archiso.cfg \
          --dhcp-option-force=210,http://192.168.0.7/arch/


Once the kernel is started from PXE, SquashFS files and other misc files
inside "arch" directory must be loaded (second stage). One of the following
methods can be used to serve the rest of live-medium.

* HTTP

# darkhttpd /run/archiso/bootmnt


* NFS

# echo "/run/archiso/bootmnt 192.168.0.*(ro,no_subtree_check,no_root_squash)" >> /etc/exports
# rc.d start rpcbind nfs-common nfs-server


* NBD

Note: Adjust ARCH_201207 as needed.

# cat << EOF > /tmp/nbd-server.conf
[generic]
[archiso]
    readonly = true
    exportname = /dev/disk/by-label/ARCH_201207
EOF
# nbd-server -C /tmp/nbd-server.conf



*** Build requirements

** For mkarchiso script needs these packages (build host):
 + squashfs-tools          for mksquashfs
 + libisoburn              for xorriso
 + btrfs-progs             for mkfs.btrfs (optional)

** For configs/releng build.sh needs theses packages (build host):
 + dosfstools              for mkfs.vfat
 + patch                   for patch
 + lynx                    for fetching the latest installation guide

** For these hooks needs these packages (on target root-image)
* archiso
 + (none)
* archiso_loop_mnt
 + (none)
* archiso_pxe_common
 + mkinitcpio-nfs-utils    for ipconfig
* archiso_pxe_nbd
 + nbd                     for nbd-client
* archiso_pxe_http
 + curl                    for curl
* archiso_pxe_nfs
 + mkinitcpio-nfs-utils    for nfsmount
* archiso_shutdown
 + (none)


*** Image types generated by mkarchiso.

* image-name.sfs     SquashFS image with all files directly on it.
* image-name.fs.sfs  SquashFS with only one file inside (image-name.fs),
                     which is an image of some type of filesystem
                     (ext4, ext3, ext2, xfs), all files reside on it.


*** File format for aitab.

The aitab file holds information about the filesystems images that must be
created by mkarchiso and mounted at initramfs stage from the archiso hook.
It consists of some fields which define the behaviour of images.

# <img>         <mnt>                 <arch>   <sfs_comp>  <fs_type>  <fs_size>

<img>      Image name without extension (.fs .fs.sfs .sfs).
<mnt>      Mount point.
<arch>     Architecture { i686 | x86_64 | any }.
<sfs_comp> SquashFS compression type { gzip | lzo | xz }.
<fs_type>  Set the filesystem type of the image
           { ext4 | ext3 | ext2 | xfs | btrfs }.
           A special value of "none" denotes no usage of a filesystem.
           In that case all files are pushed directly to SquashFS filesystem.
<fs_size>  An absolute value of file system image size in MiB.
           (example: 100, 1000, 4096, etc)
           A relative value of file system free space [in percent].
           {1%..99%} (example 50%, 10%, 7%).
           This is an estimation, and calculated in a simple way.
           Space used + 10% (estimated for metadata overhead) + desired %


*** Why the /isolinux and /arch/boot/syslinux directories?

The /isolinux directory holds files needed for the ISOLINUX boot loader
module of SYSLINUX. ISOLINUX can not find config files on
/arch/boot/syslinux, like other boot loaders modules (EXTLINUX, SYSLINUX, etc).
When make your custom boot-pendrive, you need to copy /arch directory to it.
/isolinux/isolinux.cfg just holds /arch/boot/syslinux/syslinux.cfg


*** Know issues

** (1) On shutdown lots of messages from systemd like:

    "Could not unmount /run/archiso/<ABC>: Device or resource busy"
    "Could not delete loopback /dev/loop<N>: Device or resource busy"
    This is not a real issue since, all mounted filesystem, loopback devices
    and device mapper devices made by archiso will be "free" on "shutdown tmpfs"
    (A.K.A deinitramfs), build at initramfs by [archiso_shutdown] initcpio hook.
    Proper shutdown is mostly important when persistent is used.

** (2) syslinux 4.05 bug with relative directories on FAT:

    "Could not find kernel image: boot/syslinux/whichsys.c32"
    This should be fixed in 4.06. For now, workaround with:
    sed -i "s|../../|/arch|" /<MNT-TARGET-N>/arch/boot/syslinux/syslinux.cfg


*** Building the most basic Arch Linux live media. (configs/baseline)

* Install needed packages.
  # pacman -S git make squashfs-tools libisoburn rsync --needed

* Install archiso.
  # git clone git://projects.archlinux.org/archiso.git
  # make -C archiso install

* Build a basic iso.
  # /usr/share/archiso/configs/baseline/build.sh

Note: If you want to customize, just see the configs/releng directory which is
used to build official images with much more things.


*** Building official Arch Linux live media. (configs/releng)

* Install needed packages.
  # pacman -S git make squashfs-tools libisoburn dosfstools lynx patch --needed

* Install archiso.
  # git clone git://projects.archlinux.org/archiso.git
  # make -C archiso install

* Build them!
  # /usr/share/archiso/configs/releng/build.sh build all

Note: See build.sh -h for more options.
