STEFFENS, Michael
2010-Mar-26 07:06 UTC
[syslinux] Availability of a variable of the TFTP server IP addressto be used in pxelinux.cfg/default
Hello Shao, Thank you for your hint. I saw this one already earlier but I wanted to avoid it for two reasons: - One of my images uses a CPIO INITRD which I found rather complicated editing (like I wrote I'm quite new to all that Linux stuff). - For each new release I will need to do the changes to the prebuilt images again. I'm not the one who creates the images. I'm downloading prebuilt open source tools and customize them to be PXE bootable, in some cases I also customize the INITRD which is simple when it can be mounted with the "mount -o loop ...". Also for the information passed to the Linux OS via the APPEND in pxelinux.cfg/default I don't even know how/where these are passed/executed. I expect to find it somewhere in the INITRD of the distributions but it could be also in the compressed kernel file which I simply don't know. Well, as you might have read in the lines above I try to avoid using IPAPPEND as it makes the whole thing quite complex for a novice. If there's nothing else that would be the way to go then but... Am I really the only one having the same boot images deployed to many different PXE/TFTP servers? How are others passing PXE/TFTP server specific information to the PXE bootable OS? Especially when I read in the docs that the usage of IPAPPEND is not recommended. Thanks, Michael This message may contain information that is confidential and/or protected by law. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution, copying or communication of this message is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete the message. Please note that although we will take all commercially reasonable efforts to prevent viruses from being transmitted from our systems, it is the responsibility of the recipient to check for and prevent adverse action by viruses on its own systems. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
Miller, Shao
2010-Mar-26 11:50 UTC
[syslinux] Availability of a variable of the TFTP server IPaddressto be used in pxelinux.cfg/default
Good day Michael, In regards to your challenge of passing the boot-server info on to Linux from PXELINUX: Items passed with the APPEND directive are available to Linux at /proc/cmdline . /proc/ should be mounted at some point during Linux' startup processes. IPAPPEND will add to what you find there. I've seen communications from H. Peter Anvin expressing an interest in supporting variables in Syslinux. It isn't implemented at this time. For some folks booting Linux, their Linux will itself perform another DHCP transaction... If you can use a Linux DHCP client to gain access to the boot-server information, that's another way your Linux can find out the boot server. An initramfs "initrd" can be extracted into a directory. You can modify the files and directory structure, then rebuild it. See linux/Documentation/filesystems/ramfs-rootfs-initramfs.txt for more information there. If you are customizing Linux distributions to be PXE-bootable, I'm under the impression you'd have to customize each new release anyway. If that's not the case, you might check to see if the distribution's author/vendor/distributor already has a preferred, network-bootable flavour. If so, you might be able to determine how they make use of the boot-server IP information. - Shao Miller
Ferenc Wagner
2010-Mar-26 13:14 UTC
[syslinux] Availability of a variable of the TFTP server IP addressto be used in pxelinux.cfg/default
"STEFFENS, Michael" <Michael.STEFFENS at newellco.com> writes:> Also for the information passed to the Linux OS via the APPEND in > pxelinux.cfg/default I don't even know how/where these are > passed/executed. I expect to find it somewhere in the INITRD of the > distributions but it could be also in the compressed kernel file which I > simply don't know. > > Well, as you might have read in the lines above I try to avoid using > IPAPPEND as it makes the whole thing quite complex for a novice. If > there's nothing else that would be the way to go then but... Am I really > the only one having the same boot images deployed to many different > PXE/TFTP servers? How are others passing PXE/TFTP server specific > information to the PXE bootable OS? Especially when I read in the docs > that the usage of IPAPPEND is not recommended.The solution detailed at http://syslinux.zytor.com/wiki/index.php/Comboot_API wasn't accepted. But that page mentions the -dhcpinfo option of linux.c32, which is available in the stock binaries. -- Cheers, Feri.
H. Peter Anvin
2010-Mar-29 22:52 UTC
[syslinux] Availability of a variable of the TFTP server IP addressto be used in pxelinux.cfg/default
On 03/26/2010 12:06 AM, STEFFENS, Michael wrote:> > Well, as you might have read in the lines above I try to avoid using > IPAPPEND as it makes the whole thing quite complex for a novice. If > there's nothing else that would be the way to go then but... Am I really > the only one having the same boot images deployed to many different > PXE/TFTP servers? How are others passing PXE/TFTP server specific > information to the PXE bootable OS? Especially when I read in the docs > that the usage of IPAPPEND is not recommended. >ipappend 1 is not recommended for anything long term because it means DHCP leases will not be renewed. This is a very bad thing, especially if the network you're on has short leases. However, all you need it for is something "immediate", i.e. download another file, it serves the purpose just fine. ipappend 2 has no such problem; all it does is identify the boot interface by its MAC address. -hpa
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- Availability of a variable of the TFTP server IP address to be used in pxelinux.cfg/default
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