chroot

1. Mount some necessary resources

ARCH_ROOT=/home/fancy/archlinux-root

# mount necessary resources
sudo mount --bind $ARCH_ROOT $ARCH_ROOT
sudo mount -t proc 	/proc 	$ARCH_ROOT/proc
sudo mount --rbind 	/sys 	$ARCH_ROOT/sys
sudo mount --rbind 	/dev 	$ARCH_ROOT/dev
sudo mount --bind -o ro /tmp/.X11-unix $ARCH_ROOT/tmp/.X11-unix
sudo cp /etc/resolv.conf $ARCH_ROOT/etc/resolv.conf

# umount
sudo umount --recursive $ARCH_ROOT
#sudo umount $ARCH_ROOT/dev 
#sudo umount $ARCH_ROOT/proc 
#sudo umount $ARCH_ROOT/sys 
#sudo umount $ARCH_ROOT
#sudo umount $ARCH_ROOT/tmp/.X11-unix
#sudo chmod 1777 /dev/shm

2. X related to enable GUI in chroot

# in host, authorize clients
xauth extract $ARCH_ROOT/root/.Xauthority :0

# chroot to guest
sudo chroot $ARCH_ROOT

# in guest
export XAUTHORITY=/root/.Xauthority
# test in guest, assume arch
pacman -S xorg-eyes  #xorg-xauth xorg-server
xeyes

3. Another way to display in current X window

# in host, need bind /tmp/.X11-unix
# disable access control
xhost +

# in guest
xeyes

Another way to display in a nested X window

# in host,need bind /tmp/.X11-unix
sudo apt install xserver-xephyr
Xephyr -screen 1024x768 :1 &

# in guest
DISPLAY=:1
xeyes