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Chained iPXE and ISO via http
2014-07-21, 10:17
Post: #2
RE: Chained iPXE and ISO via http
Most likely you're dealing with a web server that isn't configured to allow Range-Requests, which is required for sanboot from HTTP to work. Both apache and nginx allow this in the default configuration, but you haven't shared which web server you're using. You can verify that your web-server is actually allowing range-requests using wget or curl. If you specify a range of say 1024 bytes and it actually downloads the entire file, then your web server is not supporting that request properly. If so, figure out how to configure it for it or switch to another web server software.

Also, be aware that sanboot only loads tiny chunks of the file into memory as it is requested, unlike memdisk that reads it all in before the MBR is executed. It shouldn't really make a difference in the end. The only thing that is different is that memdisk mounts your image read-write, while sanboot mounts it read-only. I've noticed this difference using floppy images, but for ISO images it shouldn't really make any difference.

Also, sidenote - any reason why you aren't just loading the kernel directly from iPXE instead of wrapping it in an ISO with an MBR and a bootloader?

Also, if this is a custom Linux "distro", I'm very curious as to how you build it, as I've been thinking about doing this myself for a custom utility I'd like to boot up into a bunch of machines, but I haven't really found a build-tool I like yet. What are you using?

The absolutely last thing I want to mention is that you can use memdisk from iPXE as well. Load memdisk as a kernel and specify the ISO you want to load as the initrd. I believe there is already an example of that in my example script (which you mentioned you have looked at).
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RE: Chained iPXE and ISO via http - robinsmidsrod - 2014-07-21 10:17

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