deutrino's picture

Hi folks, long story short I have clients who prefer some "mom & pop" cloud providers who have to manually add a .iso image to their control panel before one can boot a VPS from a custom image with them. This provider offers all manner of images and are fine with Turnkey so I'm not trying to bend the rules, just cut down on waiting for a support ticket.

Curious if anyone has a surefire method to boot an arbitrary .iso from e.g. a stock Debian 9 or 10 system, or something like System Rescue CD. I tried a number of things with System Rescue CD, but never got anything to work. Seems like maybe the best method might be to use grub's isoboot capability, I'm just wondering if anyone knows of any guides or has any tips before I try to possibly reinvent the wheel.

deutrino's picture

um. apparently the forum ate my entire original post.

anyway, wondering if anyone has any surefire ways to boot an arbitrary .iso from either a generic Debian install, or something like System Rescue CD. I am working with a client's preferred host who is fine with us using Turnkey, but have to manually add .isos to their control panel, and I'm looking to cut down on waiting for a support ticket each time, and just be able to boot the Turnkey .isos (or .ova / .vmdk if somehow applicable, I haven't checked exactly what type of virtualization is in use yet) from within a boot .iso they already offer.

Jeremy Davis's picture

Re your post getting eaten, I was under the impression that it only happens (sometimes) with new users who are filtered by the spam filtering mechanisms (i.e. that I haven't modified their user account), but it seems I was wrong!? I wonder what happens when that occurs? I haven't hit it for a long time, but it appears to happen more with first post in a new thread (and that's something I rarely do).

Anyway, TBH, I'm not really sure. I know that grub can boot from an ISO, but it needs to know the name of the file, plus it needs to know where to find the file. AFAIK, that is often used on "multiboot" USB sticks with various ISO files copied onto the USB.

Whether that functionality could be somehow leveraged to support your desired boot scenario, I'm not sure. Possibly?

Also, I'm not sure if it's of any value, but Syslinux (which provides ISOlinux; the bootloader our ISO uses) is capable of chainloading ISOs too AFAIK. Although again, I'm not sure if that's of value...?

Alvaro Gilabert's picture

if they are using some sort of VPS, have you tried to boot using rescue mode? taking their wordpress iso as an example, you can write directly to disk

curl | dd of=/dev/sda

depending on their configuration, you can boot into rescue mode using /dev/sdb, download the iso file and then boot from /dev/sda

Jeremy Davis's picture

Thanks for sharing Alvaro. I've never considered an approach like that, but could be a winner?! Certainly worth a try.

Alvaro Gilabert's picture

20 years after being mentioned on bugtraq, 15 years after being thanked by Ponce de Leon, I am now being thanked by Jeremy Davis himself.

"See, honey? I'm an Internet super-star"



Alvaro Gilabert's picture

Hi Jeremy,

I have booted and installed your WordPress v16 on Linode, so let me recap the steps in an orderly fashion since I recall they will be the same for almost any VPS out there. Your VPS provider needs to have a graphic console option, which most do.

Since Linode uses kubernets by Google, you need to select Direct to Disk in all disks that you provision. That would be similar to selecting no kernel or a raw disk in a Hyper-V or similar installation.

1 - Provision a disk with 912Mb and label it "WordPress v16 Turnkey DVD"

2 - Provision a disk with at least 6Gb and label it "WordPress". This will end up being your webserver.

3 - Boot in rescue mode, with your "WordPress v16 Turnkey DVD" disk as /dev/sda

4 - Once you have the root bash, enter

curl | dd of=/dev/sda

5 - Follow the installation as you would do in local environment using the graphical console

6 - Shutdown the VPS

7 - Configure your VPS to run "WordPress" as /dev/sda and "WordPress v16 Turnkey DVD" as /dev/sdb. Make sure your root or boot device is /dev/sdb (that is, the disk that we created in Rescue Mode)

8 - Using the graphical console, install Turnkey WordPress on /dev/sda. Go with the suggested values (LVM, swap, 90%) and be sure to write grub on /dev/sda

9 - Shutdown the VPS

10 - Alter the configuration of the VPS so it boots from /dev/sda and disconnect /dev/sdb

11 - Optional: Keep /dev/sdb in place, just in case you need to reinstall or even create a second instance of Turnkey WordPress.




Jeremy Davis's picture

I'm sure that this will be of value to others! Thanks :)

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