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I have a PXE menu configuration that I'm working on. It incorporates the RHEL6 Rescue option in order to perform repairs after booting from the network. The Rescue boot environment asks three basic questions to set itself up: Language, Keymap, and source for the rescue image.

I have the first two sorted by adding the "lang=" and "keymap=" options to the "append" line in the PXE menu:

label rescue
    kernel /images/rhel6-3/vmlinuz
    ipappend 2
    append initrd=/images/rhel6-3/initrd.img LANG=en_US.UTF-8 KEYMAP=us rescue

What I'm curious about now is how to tell the rescue environment to get the rescue image from a URL. I'm unfamiliar with all of the kernel options and Rescue mode seems to be a special case anyway. I tried "URL=", but that doesn't do anything.

Is this possible?

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up vote 3 down vote accepted

In my PXEBoot setup, I use DHCP and a ksdevice specification to tell the booting kernel where to go and get its info.

For example:

  APPEND text initrd=images/centos/4/i386/initrd.img ramdisk_size=128000 ip=dhcp ksdevice=eth1 method=nfs:
l/centos/4/i386 rescue

Here I am using NFS over the private network but a URL should work as well. If you are using domains, then your DHCP will also need to setup the DNS which is why I use IP addresses.

On our DHCP server-side, we have all server's MAC addresses mapped so they get the same IPs.

We have a pxeboot menu that lets us drop into any install image (CentOS 4-6 (i386/x86_64) as well as their corresponding rescue modes.

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I was just about to answer this myself indicating that Redhat has provided information which is identical to what you've stated. – theillien Jun 14 '13 at 10:25

I think not. You would need to boot diskless for that. And it would not be an url - when the kernel start the machine does not even have an IP address, so it has to make do with the bootp protocol.

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