Step 1: Download Ubuntu 18.04 from Link:

Step 2: Install Ubuntu.

  • Select install Open SSH
  • Set the hard disk. You should give all hardisk you have for ubuntu_lv

Step 3: Login as root:

  • Login by account you use to create ubuntu 18.04
  • go to root by command sudo -i
  • Set password for root by command: passwd
  • Allow root access over SSH run command: sed -i -e "s/.*PermitRootLogin .*/PermitRootLogin yes/" /etc/ssh/sshd_config
  • Run command: service sshd restart
  • Delete account you created:
    • exit
    • login by root account
    • userdel [username you created]

Step 2: Add repository to end of file: /etc/apt/sources.list

deb [trusted=yes] ./

Step 3: 

  • Make sure your server can connect to internet
  • Run bellow commands
    • echo "nameserver" > /etc/resolv.conf
    • apt-get update
    • apt-get purge
    • apt-get install pnetlab -y

Note: May be get error in installing process. run apt-get update then install pnetlab again  apt-get install pnetlab -y

  • Reboot

Step 4: Upgrade to the latest version.