Install Ubuntu Linux on VirtualBox

As a quick start of trying Linux, I set up a virtual machine (VM) with Ubuntu installed.

Environment

• macOS Big Sur, Version 11.5.2.
• VirtualBox 6.1.30.

Install VirtualBox

VirtualBox is an open-source virtual machine manager. It can be downloaded from: https://www.virtualbox.org/wiki/Downloads.

After the installation, unblock it in the macOS setting to avoid the error of “Kernel driver not installed (rc=-1908)” when starting a VM:

1. Open macOS System Preferences > Security & Privacy > General.
2. Unlock the setting via Click the lock to make changes.
3. Allow apps downloaded from: App Store and identified developers.
4. Click Allow to unblock System software from developer "Oracle, America Inc." was blocked from loading.
5. Restart macOS.

Create a new VM

Open VirtualBox and then follow the steps below:

1. Open Machine and then click New.
   • Name: (name of the VM)
   • Machine Folder: (where the VM will reside)
   • Type: Linux
   • Version: Ubuntu 64-bit
2. Select Memory size: (e.g., 10240 MB).
3. Config Hard disk.
   • Select Create a virtual hard disk now.
   • For Hard disk file type, select VDI (VirtualBox Disk Image).
   • For Storage on physical hard disk, select Dynamically allocated.
   • Select File location and size: (e.g., 100GB).
4. Click Create to create the VM.

Install Ubuntu Server

Download Ubuntu from https://ubuntu.com/download/server. We use 20.04.2 , the latest LTS (long term support) release.

To attach the ISO file to the VM, configure VirtualBox as below:

• Open Settings and then select Storage.
• Under the Storage Devices section, select the Empty item.
• Under the Attributes section, click the disk icon and select the Choose a disk file option.
• Open the ISO file.

Start the VM in the Normal Start mode to proceed with the Ubuntu installation. In case of the error: “Failed to open a session for the virtual machine”, kill the VirtualBox process (via Activity Monitor by selecting the virtualBox process and then clicking the Stop button) and then start VirtualBox again.

Install Ubuntu Desktop

The Ubuntu Desktop package is required for accessing the GUI (Graphical User Interface). One way to get the GUI is to use the ISO of Ubuntu Desktop for the Ubuntu installation on the VM. Since we already got Ubuntu Server installed, we can just install the Ubuntu Desktop package.

$ sudo apt-get update
$ sudo apt-get install ubuntu-desktop

Restart the VM in the “Normal Start” mode should direct it to the GUI.

GNOME is the default GUI for most Ubuntu installations. Now we should be able to check the version of GNOME as well.

$ gnome-shell --version
GNOME Shell 3.36.9

Access to the VM

One convenient way of accessing the VM is to use network port forwarding.

• Open Settings and then select Network.
• Under Adapter 1, unfold the Advanced option and then click Port Forwarding.
• Add the configuration (some examples as below).

With the above network port forwarding, the VM can be accessed via:

$ ssh username@localhost -p 2222

OpenSSH provides a way to record such SSH option for each remote machine through a per-user configuration located at ~/.ssh/config. A new entry can be added for this VM:

Host vm
    HostName localhost
    User username
    Port 2222

Then the VM can be accessed by:

$ ssh vm

To avoid typing the password every time, we can use SSH keys for authenticating hosts and users.

1. Create an SSH key pair on the host machine. I leave all prompts empty (i.e., using the default location to save the key and ignoring the passphrase).

   $ ssh-keygen
   Generating public/private rsa key pair.
   Enter file in which to save the key (/home/username/.ssh/id_rsa): 
   Created directory '/home/username/.ssh'.
   Enter passphrase (empty for no passphrase): 
   Enter same passphrase again: 
   

2. From the host machine, copy its public key to the VM.

   ssh-copy-id -i ~/.ssh/id_rsa.pub username@vm