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iscsi-init LINUX boot

                iSCSI boot initialization module for Linux
		              version 4.0.2.*

    The module iSCSI-init may be helpful if you intend to get your root filesystem on
iSCSI LUN. There is nothing tricky, you just need to build the Initial RAM Disk right.
You'll have to load your network interface card driver as a module from INITRD, iSCSI
initiator module iscsi_sfnet (see http://linux-iscsi.sourceforge.net/), and then just
load iscsi_init module which is doing all dirty work of initializing the network
interface, configuring need environment and controlling iSCSI module to start iSCSI
boot session. DHCP/BOOTP code for iSCSI-init is mostly derived from ipconfig.c kernel
module. There are four kernel arguments supported by iscsi_init module:

 - iscsi-if=<if_name1>[:<ip_addr1>:<netmask1>:<gateway>][,<if_name2>[:<ip_addr2>:<netmask2>]]
   initializes specified network interface like eth0, eth1, etc. This is not mandatory
   parameter and you can omit it. In this case the first available interface will be
   chosen. As an optional parameters you can specify an IP address, netmask, and default
   gateway for the interface. In this case the module will skip dynamic interface
   initialization via DHCP and assign an IP address to the interface statically.
   Multiple interfaces can be listed in this parameter via comma. Please keep in mind
   that interfaces will be configured in the same order as they listed in this option.

 - iscsi-initiator=<initiator_name>
   this is not mandatory parameter. The initiator name should be specified here. This
   parameter can be obtained via DHCP "option root-path" as well. Just keep in mind
   that kernel arguments take precedence over parameters retrieved via DHCP.

 - iscsi-target=[if_name1:]<target_ip1>:<target_name1>[,[if_name2:]<target_ip2>:<target_name2>]
       or
   iscsi-target=[if_name1:]<target_ip1>[,[if_name2:]<target_ip2>]:<target_name>
   this is not mandatory parameter. You can omit it here and specify in "option root-path"
   of your DHCP server configuration. This kernel argument also takes precedence over
   parameter retrieved via DHCP. You can specify here multiple targets or multiple IP's
   for targets. Use comma as separator. Prefixed if_name's will induce routing table setup
   for target IP's which don't belong to subnets on these interfaces. It may be useful for
   multipath configurations.

 - iscsi-timeout=<seconds>
   In most cases you don't have to specify this option. Default value 5 sec. is quite
   reasonable timeout for most environments. Use this option to increase timeout
   in very congested network environments.

The format of DHCP "option root-path" is next:
--
option root-path "[if_name1:]<target_ip1>[,[if_name2:]<target_ip2>]:/<target_name>[/<initiator_name>]";
--
For example:
--
option root-path "192.168.1.2:/iqn.1992-08.com.netapp:sn.16804546/iqn.1987-05.com.cisco:01.26ffb046ec";
--
or without initiator name:
--
option root-path "192.168.1.2:/iqn.1992-08.com.netapp:sn.16804546";
--
or with multiple targets listed via comma:
--
option root-path "192.168.1.2:/iqn.1992-08.com.netapp:sn.16804546,192.168.2.2:/iqn.1992-08.com.netapp:sn.16804874";
--
or with multiple portal groups and binding to interfaces eth0 and eth1:
--
option root-path "eth0:192.168.1.2,eth1:192.168.2.2:/iqn.1992-08.com.netapp:sn.16804546:/iqn.1992-08.com.netapp:sn.16804874";
--
Please keep in mind that multiple targets can be also obtained via multiple interfaces for DHCP "root-path".

Your bootloader configuration could be like this:
--
title Fedora Core (2.6.10-1.741)
      root (hd0,0)
      kernel /vmlinuz-2.6.10-1.741 ro root=/dev/sda1 iscsi-if=eth0 iscsi-initiator=iqn.1987-05.com.cisco:01.26ffb046ec iscsi-target=192.168.1.2:iqn.1992-08.com.netapp:sn.16804546
      initrd /initrd-2.6.10-1.741-iscsi.img
--
or if you want to assign an IP statically:
--
title Fedora Core (2.6.10-1.741)
      root (hd0,0)
      kernel /vmlinuz-2.6.10-1.741 ro root=/dev/sda1 iscsi-if=eth0:192.168.1.10:255.255.255.0:192.168.1.1 iscsi-initiator=iqn.1987-05.com.cisco:01.26ffb046ec iscsi-target=192.168.1.2:iqn.1992-08.com.netapp:sn.16804546
      initrd /initrd-2.6.10-1.741-iscsi.img
--
or for multiple static interfaces:
--
title Fedora Core (2.6.10-1.741)
      root (hd0,0)
      kernel /vmlinuz-2.6.10-1.741 ro root=/dev/sda1 iscsi-if=eth0:192.168.1.10:255.255.255.0:192.168.1.1,eth1:192.168.2.10:255.255.255.0 iscsi-initiator=iqn.1987-05.com.cisco:01.26ffb046ec iscsi-target=192.168.1.2:iqn.1992-08.com.netapp:sn.16804546
      initrd /initrd-2.6.10-1.741-iscsi.img
--
or if you prefer to get everything via DHCP:
--
title Fedora Core (2.6.10-1.741)
      root (hd0,0)
      kernel /vmlinuz-2.6.10-1.741 ro root=/dev/sda1 iscsi-if=eth0
      initrd /initrd-2.6.10-1.741-iscsi.img
--
or via DHCP with multiple interfaces:
--
title Fedora Core (2.6.10-1.741)
      root (hd0,0)
      kernel /vmlinuz-2.6.10-1.741 ro root=/dev/sda1 iscsi-if=eth0,eth1
      initrd /initrd-2.6.10-1.741-iscsi.img
--

    You can run iscsid daemon later on after booting. However, you must use different
initiator name for your iscsid sessions.

    The module has the same facilities as CONFIG_IP_PNP kernel option, i.e. it will assign
nodename, domainname, and support /proc/net/pnp for your name services configuration
according to the parameters obtained via DHCP. The sample of dhcpd.conf for isc-dhcpd v3
you will find in this package. A modified Initial Ram Disk for Fedora Core could be like
below:
--
bin
  *insmod
  @hotplug -> /sbin/nash
  @modprobe -> /sbin/nash
  *nash
  *udev
  @udevstart -> udev
dev
  -console
  -null
  +ram
  -sstty
  -tty1
  -tty2
  -tty3
  -tty4
etc
  udev
     udev.conf
  iscsi.conf
lib
  crc32c.ko
  e1000.ko
  ext3.ko
  iscsi_init.ko
  iscsi_sfnet.ko
  jbd.ko
  libcrc32c.ko
  md5.ko
  scsi_mod.ko
  scsi_transport_iscsi.ko
  sd_mod.ko
loopfs
proc
~sbin -> bin
sys
sysroot
*init
--

For SuSE Linux it could be like below:
--
bin
  *ash
  *cat
  *mount
  *umount
dev
  -console
  -fb0
  +md0
  -null
  @ram -> ram0
  +ram0
  +ram1
  +ram2
  @ramdisk -> ram0
  +sda1
  -tty1
  -tty2
  -zero
etc
  fstab
  iscsi.conf
lib
  ld-2.3.3.so
  @ld-linux.so.2 -> ld-2.3.3.so
  libc-2.3.3.so
  @libc.so.6 -> libc-2.3.3.so
  modules
    2.6.6-1.427
      kernel
        crypto
          md5.ko
          crc32c.ko
          libcrc32c.ko
        drivers
          net
            tg3.ko
          scsi
            megaraid.ko
            scsi_mod.ko
            sd_mod.ko
          fs
            jbd
              jbd.ko
            reiserfs
              reiserfs.ko
      misc
        iscsi_init.ko
        iscsi_sfnet.ko
	scsi_transport_iscsi.ko
mnt
proc
sbin
  *insmod
*linuxrc
--

Please note that linix-iscsi-4.* requires crypt and crc32c kernel modules. You
need to copy libcrc32c.ko, md5.ko, and crc32c.ko to your Initial RAM Disk and
load them from linuxrc.

The sample of init script for Fedora Core you will also find in this package.

    Optionally, you can use iscsi.conf configuration file placed in the Initial
RAM Disk. The /etc/iscsi.conf file is similar to /etc/iscsi.conf used by iscsid
daemon from linux-iscsi package. See iscsi.conf.SAMPLE for details. Please keep
in mind that ImmediateData is turned on by default in iscsi-init. If your target
does not support this option, you will have to turn it off in /etc/iscsi.conf
of Initrd.

			Installation

    This module has been tested in Fedora Core-3  with linux-iscsi initiator
version 4.0.1.11. I believe it should work everywhere with kernel 2.6.10. If it
does not, please email me. The version number 4.0.1 means it supports linux-iscsi
initiator module version 4.0.1 and higher. Third digit is reserved for local
iscsi-init vesrion numbers. If there are significant changes in linux-iscsi
initiator module which require changes in iscsi-init module, first two digits
of the version number will be derived again from the version number of
linux-iscsi and so on.

			Licensing

    This module is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or  FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

---------------------------------------------------
Igor Feoktistov <[e-mail]>