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Lpar_netboot IBM POWER lpar to install Fedora23 ends with GRUB Rescue Prompt

asked 2016-09-27 10:36:35 -0500

aixandy gravatar image

Because IBM POWER LPARs send bootp requests rather than dhcp when they are netbooted, I have decided to utilise my existing AIX NIM Master management server’s bootp and tftp services as part of my Network Install infrastructure for performing automated installs of Fedora23 linux, onto LPARs created within my POWER hardware.

Everything I have set up so far has worked:

  1. I’ve added the GRUB binary from my Fedora23 install ISO into my /tftpboot folder.
  2. Copied what I understand to be supporting pieces of software for GRUB, located at /boot on the ISO image to a /boot directory on my NIM server. I’ve located these outside my /tftpboot directory as using tcpdump I can see file being requested as /boot/?/?
  3. Updated /etc/tftpaccess.ctl to include the new /boot directory
  4. Added a customised menuentry to grub.cfg within the /boot directory.

menuentry “Install Fedora 23 (64-bit kernel)" --class fedora --class gnu-linux --class gnu --class os { linux /tftpboot/ppc/ppc64/vmlinuz ro ip=[0e:5d:44:4f:ca:0a]:none nameserver= inst.ks=nfs:nfsvers=3: initrd /tftpboot/ppc/ppc64/initrd.img }

  1. Copied the Linux kernel and initrd.img into tftpboot
  2. Added an entry to the bootp config file /etc/bootptab to ensure incoming requests from my to-be netbooted lpar are answered.


  1. Created a link to the grub binary in /tftpboot for my lpar, which is used as the boot file (bf) parameter in the above bootptab file
  2. Copied the Fedora ISO image to an NFS share, which is referenced in my kickstart file
  3. Created a customised kickstart file to configure my build

So, if I now manually condition my node, i.e. open a console window, boot to SMS mode, pick my Ethernet adapter, configure IP and do a netboot, I see it request files from the bootp server, grub take over and then install successfully, fully configured as per my kickstart file. What I have configured so far therefore works. The only issue with this is that I want to automate the builds from a centrally run script on my NIM Master, as I do with my AIX installs, so this means replacing the manual SMS steps with a call to lpar_netboot.

HMC> lpar_netboot -t ent -m 0e5d444fca0a -S -G -C -K -s auto -d auto -f -i -E LPAR_NETBOOT_DEBUG -T off "test01-mgt" "normal" "T814-1"

The LPAR_NETBOOT_DEBUG give lots of helpful information along with tcpdump .At the point where I can see, via tcpdump, approximately half of the files from /boot have downloaded, but not all, and from the debug output that ... (mais)

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answered 2016-10-03 02:20:28 -0500

aixandy gravatar image

Ok, solved it !!

Having walked away from this for a day or two, I've just reviewed my tcpdump output again. This time I realised that the problem was downloading the grub.cfg file. i.e. it hadn't got quite as far in the install process as I had first thought. To cut a long story short, when I manually conditioned the node, the boot process looked for the grub.cfg as "/boot/grub/grub.cfg", but when I use the lpar_netboot command it looks for it as "/tftpboot/grub.cfg-01-<mac_addr>. So, there is obviously some logic within the lpar_netboot command that assumes the grub.cfg will come from the same location as the grub binary. Interestingly though, it goes back to /boot/grub/PowerPC-ieee1275/* for the grub supporting software.

The plus side of this, is that now it uniquely identifies the grub.cfg to the node that's being installed, I can now execute multiple install simultaneously, each having a uniquely customized grub.cfg and named according to the lpar name.

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Asked: 2016-09-27 10:35:54 -0500

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Last updated: Oct 03 '16