Upgrading Linux With Debootstrap And Chroot

Best Case:

do-release-upgrade
do-release-upgrade -d  // dev version

Other Cases:

1. Format and Partition Hard Disk gparted - making first partition with: - fat32 format - ‘boot’ and ‘esp’ flags - including an extra partition for persistence later - likely use ext4 for linux

2. Bootstrap the OS

    ap_install binutils debootstrap
    mount /dev/hda1 /mnt
   
    /usr/sbin/debootstrap --arch $ARCH $RELEASE $MNT $URL_SRC
   

   • where:
     • $ARCH, e.g., amd64
     • $RELEASE, e.g., wily
     • $MNT, e.g., /mnt
     • $URL_SRC, e.g., http://archive.ubuntu.com/ubuntu

3. Prepare to chroot a. sysctl kernel.hostname=NEW_HOSTNAME b. Plan on copying fstab to target disk and using blkid to identify target disk UUID that will replace fstab source disk UUID c. Consider copying network info before rebooting: - /mnt/etc/network/interfaces - /mnt/etc/hosts - /mnt/etc/resolv.conf

4. Chroot into target disk/OS

    mount -t proc none /mnt2/proc; \
    mount -o bind /dev /mnt2/dev; \
    LANG= chroot /mnt2 /bin/bash
   
    passwd
    dpkg-reconfigure --default-priority passwd  // create a user and switch shadow password on
   

5. Installing Packages

   • Basics:
     • apt-get update
     • openssh-server
     • ubuntu-standard
     • linux-image-$ARCH
   • Perhaps copy “some” from existing system:
     • dpkg --get-selections | grep "install" | cut -f1
     • one list of transferred packages
   • Maybe set some environment vars

  locale-gen en_US.UTF-8
  echo 'LANG="en_US.UTF-8"' >> /etc/environment
  echo 'LANGUAGE="en_US:en"' >> /etc/environment
  ```

1. Gracefully end chroot

    exit
    cd /
   
    for i in /mnt/proc /mnt/dev /mnt
    do umount $i; done
   
   

(Primary Source)