LinuxPC

The available scripts install a Live CD version of the Linux PC for the Internet Lab on a "baremetal" PC system.
The process described here assumes that the installation is done in Virtualbox on a Mac or Windows or Linux system (The scripts also run on a native Linux installation).

Version: July 2025

1. Install Ubuntu server

For installing Ubuntu server in Virtualbox, there are excellent instructions available at https://hibbard.eu/install-ubuntu-virtual-box/ . Follow the instructions until you get to "Up and Running with SSH".

Consider the following points during the installation:

a. Download Ubuntu Server 20.04 LTS from https://ubuntu.com/download/server

b. Create a new VM. If you start the name with "Ubu", Virtualbox automatically selects Ubuntu (64-bit). Go to Settings→Ports→USB and select USB 3.0 Controller.

c. Install the Ubuntu server from the downloaded .iso file as a VM in Virtualbox (the development was done with Virtualbox 6.1). Allocate min. 2048 MB memory and min. 20 GB for the virtual disk.

During the installation, use the default settings.

• For the user name password, select Name: Labuser, username: labuser, password: labuser.
• Agree to the installation of OpenSSH server
• Once the installation is complete, Ubuntu often does not reboot. In this case, force a shut down from Virtualbox.
• In Virtualbox, check that the (virtual) optical drive containing the .iso file is removed. If not, remove it.

2. Install software on Ubuntu server

a. Start the Ubuntu server in Virtualbox and log in as labuser.

b. From the home directory of labuser clone this repository using the command

$ git clone https://github.com/Internet-lab/LinuxPC.git

c. Change to the directory LinuxPC with the command

$ cd LinuxPC

d. Execute the script with the command

$ bash InstallBaremetalPC.sh

• The script installs software packages and sets configuration files needed in the Internet Lab (as well as some additional software).
• Answer Y when prompted and select <Yes> in the screen Configuring wireshark-common.
• The script reboots the OS, when the system reboots it will show a login screen of the Gnome Desktop. Login as labuser and verify that the software installation is completed.

e. Touch up the VM

• If not already logged in, start the (Build) VM and log in as labuser.

• Change the screen background. There are templates available for PC1, PC2, ...

• Change the power saving mode to prevent that the system locks the screen after an idle period or suspends. In the Ubuntu desktop go to Settings→ Power. In Power Saving, select Never. In Suspend & Power Button, set Automatic Suspend to Off.

• In the file /usr/share/applications/wireshark.desktop, change the line Exec=wireshark %f to Exec=sudo wireshark %f.

• The snap daemon delays the shutdown process up to 90 seconds. The following instructions set the delay to 10 seconds. To do this open the file /etc/systemd/system.conf with sudo privileges, e.g., Find the line with #DefaultTimeoutStopSec=90s:

  $ sudo vi /etc/systemd/system.conf
  

  Find the line with #DefaultTimeoutStopSec=90s:

  (1) Remove #.

  (2) Change 90s to 10s.

• We want to make sure that the following services are not started at boot time:

      avahi-daemon   named  bgpd   ospfd   ospf6d  pimd   ripd   ripngd   isisd   zebra 
  

  To do this we should disable them with the commands

  $ sudo systemctl disable avahi-daemon
  $ sudo systemctl disable named
  $ sudo systemctl disable bgpd
  $ sudo systemctl disable ospfd
  $ sudo systemctl disable ospf6d
  $ sudo systemctl disable pimd
  $ sudo systemctl disable ripd
  $ sudo systemctl disable rpingd
  $ sudo systemctl disable isisd    
  $ sudo systemctl disable zebra
  

  In addition, we need to edit the service files for all of the above services and comment out a line. In each of the following files, go to the Install section of the files and put a # in front of Wanted by:

  /lib/systemd/system/avahi-daemon.service    
  /lib/systemd/system/named.service
  /lib/systemd/system/bgpd.service
  /lib/systemd/system/ospfd.service
  /lib/systemd/system/ospf6d.service
  /lib/systemd/system/pimd.service
  /lib/systemd/system/ripd.service
  /lib/systemd/system/ripngd.service
  /lib/systemd/system/isisd.service
  /lib/systemd/system/zebra.service  
  

3. Create an ISO LiveCD image

The following instructions create a LiveCD ISO image, which has the same configuration as the customized Ubuntu server.

3.1 (Optional, but highly recommended) Avoid increasing the size of VM when creating a new LiveCD.

The creation of a LiveCD from a VM expands the size of the virtual machine substantially. The reason is that for the creation of the ISO image, large parts of the Master VM are copied in a temporary directory. For this, the virtual disk of the Master VM is dynamically increased. To avoid increasing the size of the original VM of the Ubuntu server from Step 2 (Install software on Ubuntu server), create a copy of VM. We call the original VM the Master VM and the copied VM the Build VM. Proceed as follows:

• After making changes to the Master VM (running InstallBaremetalPC.sh or installing/removing packages), create a clone of the VM. The clone becomes the Build VM.
• Repeat Step 1b, i.e., selecting USB 3.0 Controller for the Build VM.
• Start the Build VM and log in as `labuser'.
• Next run the scripts to create an ISO LiveCD image and burn the ISO file to a flash drive.
• Once the flash drive is created, delete the Build VM.

Hint: Create four BuildVMs, one for each PC (PC1, PC2, PC3, PC4) and create four USB flash drives that each hold a LiveCD for one of the PCs. Label the flash drives and use them to configure the PCs in the Internet lab.

3.2 Check desktop background

Check the desktop background. Change it to match one of PC1, PC2, P3, PC4.

3.3 Run script that creates ISO image

• Check whether the Build VM has Internet access. If not, find the network interface name by typing ip link and identify the virtual network interface. Then enable the network interface (say with name enp0s3) and start a DHCP client with

  $ sudo ifconfig enp0s3 up
  $ sudo dhclient enp0s3
  

• Change the hostname. To configure a LiveCD for PC1, type

  sudo hostnamectl set-hostname PC1
  

• The script makeLiveCD.sh is in the ~/LinuxPC directory you cloned from git repository in section 2. Change to this directory with the command

cd ~/LinuxPC

• The shelll script makeLiveCD.sh creates an .iso image (“liveCD.iso”) from the current virtual machine. Run the script with the command

$ bash makeLiveCD.sh

The script asks a few times for information. If you do not know otherwise, select the default option. The default location of the ISO script is /tmp/liveCD/liveCD.iso. When prompted for the hostname, enter one of PC1, PC2, PC3, PC4.

Note: Since the default location of liveCD.iso is in a subdirectory of /tmp, the ISO image is lost after rebooting.

4. Create a bootable flash drive with LiveCD

4.1 Insert flash drive

Insert a flash drive (min. 16 GB) into a USB port of the computer where Virtualbox is running. The flash drive must be mounted in the Build VM. Sometimes the Ubuntu VM is unable to grab the flash drive, i.e., it does not appear as a drive. In this case, select the Ubuntu VM in the VM Manager and go to Settings→ Ports → USB, and add the flash drive. Then removing and re-inserting the flash drive should show it in the Ubuntu VM.

Note: Using USB flash drives on a Virtualbox VM requires the installation of the Virtualbox Extension Pack. Follow the online instructions fo installing the pack.

Note: For Linux hosts: If the Build VM cannot find the flash drive, then the user labuser may need to be added to the vboxusers group. Go to the Linux host and issue

$ sudo adduser labuser vboxusers

After this, restart Virtualbox. It may be a good idea to also reboot the Linux host system.

4.2 Install LiveCD on flash drive

a. The script createBootableUSB.sh is in ~/LinuxPC directory you cloned from git in section 2.

cd ~/LinuxPC

b. Identify the device name of the flash drive with the command

$ sudo lsblk -p

Typically, the device name is /dev/sdb with one partition /dev/sdb1 (It can be /dev/sdc or /dev/sdc1).

c. From the ~/LinuxPC directory, run the script with the command

$ bash createBootableUSB.sh

The script prompts for hardware specific information. In particular, the script requests to enter the device name of the flash drive (/dev/sdb). Once the script is completed, remove the flash drive. The flash drive contains the ISO image (liveCD.iso) and grub configuration files.

5. Installing the LiveCD on the hard drive

Thee following instructions install the LiveCD on the hard drive of the target machine.

Note: Copying the LiveCD to the hard drive will delete all partitions on the hard disk. All data on the hard disk will be lost.

a. Check if the BIOS of the target machine is set so that the system first tries to boot from a flash drive.

b. Insert the flash drive from Step 4 into the target system. Rebooting the target system starts the LiveCD from the flash drive. Log in as labuser.

c. You need to copy the shell script createBootableUSB.sh to the home directory of labuser. One option is to copy the file on a flash drive (different flash drive than created in Step 4). An alternative is to connect the target machine to the Internet and download the file.

• To get Internet access, connect one of the Ethernet interfaces to an network with access to a DHCP server und run the command

$ sudo dhclient

d. Identify the device names of the hard disk on the target system.

$ sudo lsblk -p

In many cases the hard disk is /dev/sda. Verify that this is the case.

e. From the home directory of labuser, run the script with the command

$ bash createBootableUSB.sh

When the script requests to enter the device name of the target drive, enter /dev/sda. If entered for the path of the ISO file, enter /isodevice/.
f. Once the script has completed, reboot the target machine and remove the flash drive.