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--- sanboot:debian_etch_iscsi [2007/10/25 10:06]
gervystar
+++ sanboot:debian_etch_iscsi [2007/11/06 08:25]
gervystar
@@ Line 10: / Line 10: @@
 This howto is based on the following assumptions:
-   * a base debian >= etch with all the security updates
+   * a base debian etch with all the security updates
    * the system is installed on a single partition "/" on /dev/sda1
    * there is an already done iscsi target on an iscsi server
    * there is a working dhcp server
-Install the ''open-iscsi'' package.
+==== Compile iscsistart and fwparam_ibft ====
-   apt-get install open-iscsi
 Since two fundamental tools from open-iscsi are not included in the debian package, they have to be compiled from the sources with the following steps (i have used a different machine for all the compilation stuff).
@@ Line 35: / Line 33: @@
 The two files needed are ''usr/iscsistart'' and ''utils/fwparam_ibft/fwparam_ibft'' so they have to be copied in ''/usr/sbin''.
+==== Install the needed packages ====
+   apt-get install iproute
+==== Disable networking scripts ====
+The file ''/etc/network/interfaces'' must contain only the information needed to setup the loopback adapter or some additional network cards not used in the iSCSI boot process.
+If you have only one interface (in example eth0), be sure to have a stanza like this in ''/etc/network/interfaces''
+<code>
+auto eth0
+iface eth0 inet manual
+</code>
+So ifupdown will report the network card as "up", otherwise some script will not work well (in exemple the nfs mount).
+==== Create the initramfs scripts ====
 Create two scripts shown below. These scripts have to be executable.
@@ Line 45: / Line 61: @@
 you can update the initial ramdisk:
    dpkg-reconfigure linux-image-$(uname -r)
+If the modifications were applied to a physical disk on the client
+machine, you can now [[sanboot:transfer|transfer the contents of your
+physical disk to the SAN target]].
+If the image you wish to export to client systems was modified directly,,
+you can now [[sanboot:iscsitarget|make the contents of that image available
+via iSCSI]].
+==== Hint ====
+   * If the system hangs before the root device has been mounted, passing ''break=mount'' on the command line will spawn a shell before ''scripts/local-top/iscsi_tcp'' is run. This should allow for further debugging.
+==== Scripts ====
+=== /etc/initramfs-tools/hooks/iscsi_tcp ===
+<code bash>
+#!/bin/sh
+set  -e
+PREREQ=""
+prereqs()
+{
+        echo "$PREREQ"
+}
+case $1 in
+prereqs)
+        prereqs
+        exit 0
+        ;;
+esac
+. /usr/share/initramfs-tools/hook-functions
+[ -x /usr/sbin/iscsistart ] && copy_exec /usr/sbin/iscsistart /sbin
+[ -x /usr/sbin/fwparam_ibft ] && copy_exec /usr/sbin/fwparam_ibft /sbin
+[ -x /sbin/ip ] && copy_exec /sbin/ip /sbin
+manual_add_modules iscsi_tcp
+manual_add_modules ib_iser
+</code>
+=== /etc/initramfs-tools/scripts/local-top/iscsi_tcp ===
+<code bash>
+#!/bin/sh
+set -e
+PREREQ="udev"
+prereqs()
+{
+        echo "$PREREQ"
+}
+case $1 in
+prereqs)
+        prereqs
+        exit 0
+        ;;
+esac
+case $ROOT in
+/dev/sd*)
+        # Evaluate IBFT parameters
+        for i in $(fwparam_ibft -b); do export $i; done
+        #Bring up the interface used to boot
+        for i in $(ls /sys/class/net); do
+                IFADDR=$(cat /sys/class/net/$i/address)
+                if [ $IFADDR = $iSCSI_INITIATOR_HWADDR ]; then
+                        echo "Using $i with MAC $IFADDR"
+                        export iSCSI_INITIATOR_IF=$i
+                fi
+        done
+        modprobe -q iscsi_tcp
+        modprobe -q ib_iser
+        echo "Bringing up $iSCSI_INITIATOR_IF for iSCSI..."
+        ip link set $iSCSI_INITIATOR_IF up
+        echo "Setting up networking on $iSCSI_INITIATOR_IF..."
+        ip addr add $iSCSI_INITIATOR_IPADDR/$iSCSI_INITIATOR_MASK brd + dev $iSCSI_INITIATOR_IF
+        ip route add default via $iSCSI_INITIATOR_GATEWAY
+        echo "Connecting to iSCSI target $iSCSI_TARGET_NAME on $iSCSI_TARGET_IPADDR..."
+        iscsistart -i $iSCSI_INITIATOR_NAME -t $iSCSI_TARGET_NAME -g 1 -a $iSCSI_TARGET_IPADDR
+        sleep 5
+        ;;
+esac
+</code>
+===== Using gPXE to boot over iSCSI =====
+Since my network cards don't support booting via iSCSI, I've used the great gPXE, loading it after a "standard" PXE request.
+This is called [[:pxechaining|PXE Chainloading]]
+A separate stanza containing the right ''root-path'' option should be created for each host in ''/etc/dhcp3/dhcpd.conf'', like in the example.
+<code>
+host iscsi-test {
+                hardware ethernet 00:0C:29:5C:53:C2;
+                fixed-address 192.168.23.195;
+                filename "";
+                option root-path "iscsi:192.168.23.2::::iqn.2007-10.org.appliedgenomics:test.disk1";
+}
+</code>

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