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WoJ
Asked: 2020-02-22 05:41:10 +0800 CST

How to install the OS when testing a bare-metal recovery?

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I run a home server on Ubuntu 18.04. It boots from a M2 internal drive (/dev/sda1) and basically

  • mounts another drive (/dev/sdc1)
  • mounts an LVM partition (/dev/mapper/data-data)
  • starts docker which in turn runs a set of containers

I would like to test a disaster scenario where the M2 (boot) drive fails. My backup is stored on /dev/sdc1 (and also remotely, which is the same type of testing).

In order to perform the test I would like to

  • remove the M2 drive (this is to simulate its failure, and also protect from a mistake which would damage it)
  • plug in an external USB drive (USB drive 1)
  • boot from a Ubuntu ISO (flashed on USB drive 2)
  • install Ubuntu on the external drive (= on USB drive 1, and then remove and forget USB drive 2)
  • install docker and other utilities, recover the backup, start the containers etc. ← that part is simpler as I (hopefully) understand how to orchestrate the activities.

My main concern (there may be others I am not aware of) is whether the external USB drive will be recognized as a "proper" drive to install the system. Are there limitation on the kind of connectivity for an installation?

The alternative is to borrow an M2 drive and swap the existing one with the "recovery" one but I would prefer to do the testing on the USB one, which I already have.

Additionally - are there any possible problems with the testing process above? (especially the part from "disaster" to having a shell prompt and start the last point -- I am sure I will discover a lot of problems in the last one but I will be able to handle them fine, the booting process which I am not that acquired with is the one I do not feel comfortable with)

system-installation data-recovery backup hard-drive

1 Answers

  1. Best Answer

    Sample grub menu entry to run live Ubuntu ISO-image:

    menuentry "Try Ubuntu without installing 18.04.3" {
  loopback loop /boot/images/ubuntu-18.04.3-desktop-amd64.iso
    set gfxpayload=keep
    linux   (loop)/casper/vmlinuz iso-scan/filename=/boot/images/ubuntu-18.04.3-desktop-amd64.iso   file=(loop)/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
    initrd  (loop)/casper/initrd
}

    Sample for installing Ubuntu from mini-ISO:

    menuentry "Ubuntu mini 18.04 64bit cli expert" {
 loopback loop /boot/images/ubuntu__18.04__mini64.iso
 linux (loop)/linux iso-scan/filename=/boot/images/ubuntu__18.04__mini64.iso tasks=standard pkgsel/language-pack-patterns= pkgsel/install-language-support=false priority=low --
 initrd (loop)/initrd.gz
}

    And howto install grub onto USB

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