Why doesn't automatic mounting of shared packages work in Ubuntu?

Question

linux

Hello. Installed VirtualBox on win7. Raised Ubuntu Server v16.04 on a virtual machine and decided to make shared directories between the axes. I did everything according to the manual
After running the command
sudo mount -t vboxsf domains /var/www/domains
I checked - everything works. But I don’t want to mount it manually every time, so, as indicated in the article, I made automatic mounting:
sudo echo domains /var/www/domains vboxsf defaults 0 0 >> /etc/fstab
After rebooting, the message flies:
Welcome to emergency mode! After logging in, type "journalctl -xb" to view system logs, "systemctl reboot" to reboot, "systemctl default" to try again to boot into default mode.
Give root password for maintenance
(or type Control-D to continue):
If you comment out the line in /etc/fstab that is responsible for automatically mounting the shared dir, then everything loads without errors, but you have to mount it manually. How to be?
===== SOLUTION =====
1. Do not add anything to etc/fstab !!!
2. sudo nano /etc/modules (add the line: vboxsf )
3. sudo nano /etc/rc.local
Before exit 0 add the line mount.vboxsf domains /var/www/domains vboxsf

Answer 1

add the mount command to /etc/rc.local before exit
mount -t vboxsf share /media/share

Answer 2

At boot time, the mount can (and does) happen before the VirtualBox support extensions are loaded. Therefore it fails to mount.
Systemd rules this issue - this is where you need to configure the mount after loading the VirtualBox extensions.

Answer 3

had the same problem. NOT decided. I created a shell script and added the mount command to it. Now, at the start of the virtual machine, I execute ./mnt, under the root. Haven't found anything better yet.

Answer 4

went vzhoposhny kostyling ...
it is necessary to add drivers for vboxsf to initramfs, when loading the system does not find the driver for shared folders and naturally gives a mount error.
the solution
to the file /etc/initramfs-tools/modules
is to enter the line
vboxsf at the end
and after starting the update of the initramfs
sudo update-initramfs -cu
then mounting vboxsf will become possible at any stage of loading