Vagrant was unable to mount VirtualBox shared folders

After upgrading my ubuntu/focal64 box I got greeted by this wonderful message:

Vagrant was unable to mount VirtualBox shared folders. This is usually
because the filesystem "vboxsf" is not available. This filesystem is
made available via the VirtualBox Guest Additions and kernel module.
Please verify that these guest additions are properly installed in the
guest. This is not a bug in Vagrant and is usually caused by a faulty
Vagrant box. For context, the command attempted was:

mount -t vboxsf -o uid=1000,gid=1000 vagrant /vagrant

The error output from the command was:

: Invalid argument

The solution was rather simple: A sudo apt-get install -y virtualbox-guest-dkms inside the VirtualBox guest followed by a vagrant reload at the host.

In case it matters, the VirtualBox host machine was an Ubuntu 21.04.

resizing a vagrant box disk

[ I am about to do what others have done before me and blog about it one more time ]

While I do enjoy working with Windows 10, I am still not using WSL (waiting for WSL2) and work with either chocolatey or a vagrant Ubuntu box. It so happens that after pulling a few docker images the default 10G disk if full and you cannot work anymore. So, let’s resize the disk:

The disk on my ubuntu/bionic64 box, is a VMDK one. So before resizing, we need to transform it to a VDI first, which is easier for VirtualBox to handle:

VBoxManage clonehd .\ubuntu-bionic-18.04-cloudimg.vmdk .\ubuntu-bionic-18.04-cloudimg.vdi --format vdi

Now we can resize it, to say 20G:

VBoxManage modifymedium disk .\ubuntu-bionic-18.04-cloudimg.vdi --resize 20000

We’re almost there. We need to tell vagrant to boot from the VDI disk now. To do so open VirtualBox and visit the storage settings of the vagrant VM. Remove the VDMK disk(s) there and add the VDI on SCSI0 port. That’s it. We’re one step closer. Close VirtualBox and vagrant up now to boot from the VDI.

Now you have a 20G disk, but still a 10G partition. parted to the rescue:

$ sudo parted /dev/sda
(parted) resizepart 

It will ask you the partition number. You answer 1 (which is the /dev/sda1). It will ask you for the end of the partition. You answer -1 (which means until the end of disk). quit and you’re out.

You have changed the partition size, but still the filesystem reports the old size. resize2fs (assuming a compatible filesystem) and:

$ sudo resize2fs /dev/sda1

Now you’re done. You may want to vagrant reload to check whether everything works fine. Once you’re sure of that you can delete the old VMDK disk.

Funny OpenDNS, VirtualBox and Debian weirdness

I was trying to install a virtual machine using the latest VirtualBox on a Windows 7 Host. The host was also running OpenDNS DNSCrypt 0.0.6 client. The guest operating system should be Debian/LXDE. Installation went fine until the installer tried to contact Debian mirrors to fetch missing packages.

It couldn’t find them. Like the common system administration mantra says:

Everything is a DNS problem.

So at the OpenDNS DNSCrypt client dashboard I (temporarily) disabled the DNS over TCP option and the installation continued smoothly. The same thing does not happen with OS X Mavericks as the host operating system. After the installation is finished, you can reenable DNS over TCP for DNSCrypt. The guest operating system’s resolver sees no issues with this.

I am posting this short note because it may bite others out there.