I have figured it out, linux and rootfs.gz can be copied to all site servers without any modification but to get linux pe to use the correct pxe host the pxelinux.cfg\default needs to be updated individualy on all site servers.
And I found a way to use the same rootfs.gz on other altiris installations,
Edit etc/rc.agent
vim etc/rc.agent
Find the section
cp /tmp/.aex-agent-install-config.xml $AGENT_INSTALL_DIR/
Before that line add the following text:
for x in `cat /proc/cmdline`; do echo "$x"|grep 'NS_SERVER'&&eval export $x; done
for x in `cat /proc/cmdline`; do echo "$x"|grep 'PXE_SERVER'&&eval export $x; done
if [ "$NS_SERVER" != "" ];then
cat /tmp/.aex-agent-install-config.xml|sed s:\<NSName\>.*\</NSName\>:\<NSName\>$NS_SERVER\</NSName\>:g >/tmp/.aex-agent-install-config.xml.new
mv /tmp/.aex-agent-install-config.xml.new /tmp/.aex-agent-install-config.xml
elif [ "$PXE_SERVER" != "" ];then
cat /tmp/.aex-agent-install-config.xml|sed s:\<NSName\>.*\</NSName\>:\<NSName\>$NS_SERVER\</NSName\>:g >/tmp/.aex-agent-install-config.xml.new
mv /tmp/.aex-agent-install-config.xml.new /tmp/.aex-agent-install-config.xml
fi
And on the siteservers add the following text last in the "append initrd" line in pxelinux.cfg\default file:
NS_SERVER=[your nsserver hostname/ip]
To edit your rootfs you can follow the following guide:
1.Copy rootfs.gz from to you Linux build environment.
C:\Program Files\Altiris\Altiris Agent\Agents\Deployment\SBS\Images\Linux-serial-115200\x86PC\
2.Run the following commands:
mkdir rootfs_mount
gunzip rootfs.gz
mount -o loop rootfs rootfs_mount
3. Do your changes to your roosfs.
4.Then run the following commands to create the new rootfs.gz
cd ..
umount rootfs_mount
fsck.ext2 -fpcv rootfs
gzip -9 rootfs