How to set up a chroot environment for openSUSE and SUSE Linux Enterprise

Setting up a chroot environment on openSUSE or SUSE Linux Enterprise provides an isolated system environment. It allows you to perform tasks like system recovery, package building, or testing without impacting your host system. The chroot command changes the root directory, creating a confined space where commands and processes only affect the chroot environment.

The process involves installing a minimal system with zypper, mounting essential filesystems, and accessing the chroot environment. This setup is useful for creating a clean and safe system space to handle various operations. It helps isolate your host environment from changes made inside the chroot.

The following steps guide you through installing a minimal openSUSE or SUSE system, preparing it for chroot, and entering the environment for operations. After completing your tasks, you will unmount the filesystems to safely exit.

1. Create a directory for the chroot environment.

   $ sudo mkdir /mnt/chroot

2. Install a minimal system in the new directory.

   $ sudo zypper --root /mnt/chroot install --no-recommends --type pattern minimal_base
   Loading repository data...  
   Reading installed packages...  
   Resolving package dependencies...  
   The following NEW packages are going to be installed:  
   bash coreutils filesystem glibc libgcc_s1...  
   ...  

   This command installs the minimal_base pattern, which includes the core packages needed for a basic system.

3. Mount the /proc filesystem for the chroot environment.

   $ sudo mount -t proc /proc /mnt/chroot/proc

4. Mount the /sys filesystem.

   $ sudo mount --rbind /sys /mnt/chroot/sys

5. Mount the /dev filesystem.

   $ sudo mount --rbind /dev /mnt/chroot/dev

6. Bind /dev/pts for pseudo terminals.

   $ sudo mount --bind /dev/pts /mnt/chroot/dev/pts

7. Copy DNS information for internet access in the chroot.

   $ sudo cp -L /etc/resolv.conf /mnt/chroot/etc/

8. Enter the chroot environment.

   $ sudo chroot /mnt/chroot /bin/bash  
   source /etc/profile  
   export PS1="(chroot) $PS1"

   You are now operating inside the chroot environment. Any operations you perform will only affect the chroot environment and not your host system.

9. Install necessary software inside the chroot (optional).

   $ zypper install gcc make

10. Exit the chroot environment.

    $ exit

11. Unmount /dev filesystems when finished.

    $ sudo umount -l /mnt/chroot/dev{/shm,/pts,}

12. Unmount /proc filesystem.

    $ sudo umount -l /mnt/chroot/proc

13. Unmount /sys filesystem.

    $ sudo umount -l /mnt/chroot/sys