2. Installation

  • Popular Linux distros

  • Linux installation steps

  • Ubuntu software packages (DEB packaging)

  • KVM virtualization

  • Virtual machine (VM) setup

  • Ubuntu installation on a VM

2.2. Ubuntu distributions

Available Ubuntu Releases (Links to an external site.).

21.04, 20.10, 20.04 LTS, 18.04 LTS, 16.04 LTS – The Ubuntu version numbering scheme is based on the date of the release of the distribution, October 2020, April 2020, April 2018, etc

18.04 LTS (Links to an external site.) – The LTS means long-term support (5 years). (Links to an external site.) The interim production releases are supported for 9 months.

Release – Server and Desktop editions. They have similar packages. The server may have no X-desktop environment installed.

To check what version of Ubuntu is running on your system run command: cat /etc/lsb-release Supported architectures – x86, ARM (32 bit), x86_64, amd64 (64 bit).


2.3. Installation steps, media, files.

Installation Steps:

  • Boot-up

  • Ubuntu-installer (Debian-installer)

  • Post-install base configuration

Installation boot media:

  • CD-ROM/DVD-ROM, ISO files.

  • Hard Disk

  • USB Memory Stick

  • Network

  • bootstrap from Unix system

The installation files/packages can be located on:

  • Local CD-ROM/DVD-ROM

  • Local Hard Disk

  • Remote server (HTTP, FTP, NFS)

Note: we will be installing Ubuntu on a virtual host by using a remote HTTP server (Ubuntu mirror) and an ISO file on a Hard Drive.


2.4. Boot up and installation

installation steps

2.5. Ubuntu installer stages

Hardware detection
Check available RAM
Language Chooser
Country Chooser
Choosing a Keyboard
Configuring Network
Choosing Ubuntu mirror
Downloading the Ubuntu Installer components
Partitioning Disks
Configuring Logical Volume Manager and RAID
Configuring Time Zone
Configuring the Clock
Setting Up Users And Passwords
Base System Installation
Installing Additional Software
Install the Grub Boot Loader on a Hard Disk
Finish the Installation and Reboot

Alt-F* keys
Check error messages Left Alt-F4
Get shell prompt Left Alt-F2
Go back to the installer Left Alt-F1

The error messages are logged in /var/log/syslog. After installation, this log is copied to /var/log/installer/syslog on the new system.


2.6. Disk partitioning in Linux

There are two types of drive partitioning schemes on a PC based x86_64 architecture: MBR (Master Boot Record), and GPT (GUID Partition Table).

In MBR (also known as DOS or MS-DOS partition table), there are maximum 4 primary partitions on a hard drive.

/dev/sda1
/dev/sda2
/dev/sda3
/dev/sda4

One of them can be of “extended” type and doesn’t contain a file system, but can contain logical partitions. Say,

/dev/sda1 - primary
/dev/sda2 - extended
/dev/sda5 - logical
/dev/sda6 - logical
/dev/sda7 - logical

Max number of logical partitions is 12. Their sequence number can not be skipped, unlike that for the primary partitions.

The major limitation in MBR is 2TB drive limit.

GUID Partition Table (GPT) was designed by Intel to fit into the Unified Extensible Firmware Interface (UEFI) specification, which becomes the old BIOS replacement. GPT can handle disks of 8 zebibytes, or 8.6 billion TiB capacity. It has many superior features.

fdisk, cfdisk, gdisk, and parted can be used for partitioning a drive.

File systems can be created with mkfs command

mkfs -t ext4 /dev/sda1

To create a swap partition, use mkswap

mkswap /dev/sda5

References:

Partitioning (Links to an external site.)

Make the most of large drives with GPT and Linux


2.7. Disk partitioning for OS installation

Minimum required number of partitions on Linux is 2: / and swap (starting from Ubuntu 18.04 swap it can be a file in the root file system)
For Desktops it is recommended at least 3: /, swap, /home
For Multi-user workstation – at least 6: /, /home, /usr, /var, /tmp, swap

Partitioning scheme Minimum space

Installation type

Suggested partitions

All files in one partition 600MB

/, swap

Desktop machine 1.7GB

/, /home, swap

Multi-user workstation 1.7GB +

/, /home, /usr, /var, /tmp, swap

Linux generic partition types: swap, ext2, ext3, ext4 Additional supported types: Raiser FS, jfs, xfs, zfs


2.8. Ubuntu packages

Ubuntu OS components and most of the GNU software are available in form of packages. A package file contains:

  • Software

  • Info (control) file

  • Scripts (pre/post install/remove)

Naming convention:

(package-name)_(source version)-(package-version)_(architecture).deb

For example:

g++-7_7.3.0-27ubuntu1~18.04_amd64.deb

Package name is g+±7. The source version is 7.3.0 of GNU C++ 7 series, package version (revision): 27 - debian and 1~18.04 -ubuntu, architecture: amd64.

The official Ubuntu distribution located in the Ubuntu archive,
folders main and Restricted.
In folder Restricted, there are packages with restricted vendor licensing, for example, nvidia-361.

Universe: Free software available from the network, but not officialy maintained by Ubuntu development team. For example, a2ps (“Anything to PS”), xemacs21. No guarantee of security fixes and support.

Multiverse: Packages in the archive have some onerous license condition restricting use or redistribution of the software. For example, dvd-slideshow.

You can run synaptic package manager to see what package belongs to what folder:

sudo -s
synaptic

Click on Origin to see the folders in the top left window and their packages in the top right one.

Reference: Ubuntu Repositories


2.9. Package management (dpkg)

Installation:

dpkg -i linux-image-4.15.0-43-generic_4.15.0-43_amd64.deb

Removal:

dpkg --purge linux-image-4.15.0-43-generic_4.15.0-43_amd64.deb 

queries (list of all packages):

dpkg -l '*'
dpkg -l '*kernel*'

List files in the package:

dpkg -L  ncurses-term

Info on a package:

dpkg -s ncurses-term

To find out what package owns the file:

dpkg -S ncurses-term

2.10. Advanced Package Tool (APT)

Configuration of /etc/apt/sources.list file in our class

deb http://us.archive.ubuntu.com/ubuntu/ bionic main restricted

deb http://us.archive.ubuntu.com/ubuntu/ bionic universe

deb http://us.archive.ubuntu.com/ubuntu/ bionic multiverse

deb http://us.archive.ubuntu.com/ubuntu/ bionic-updates universe main multiverse restricted

deb http://us.archive.ubuntu.com/ubuntu/ bionic-backports universe main multiverse restricted

deb http://security.ubuntu.com/ubuntu/ bionic-security universe main multiverse restricted

After updating config files and periodically, run

apt-get update

Upgrade packages

apt-get upgrade

Search for string in known packages

apt-cache search ncurses
apt-cache search --names-only ncurses

Install a package

apt-get install libcurses-perl

Check if a package has been installed and can be updated

apt-cache policy libcurses-perl

Clean the cached deb packages after installations

apt-get autoclean

More instructions on APT are available in APT manual


2.11. APT enhancements

Aptitude is a menu-driven, text-based front-end to the Advanced Packaging Tool (APT) system.

Synaptic is a graphical package management front-end for APT. It provides the same features as the apt-get command line utility with a GUI front-end based on Gtk+.

Tasksel ia a tool for selecting installation of a group of packages for specific tasks. For example, DNS, SMTP, etc.


2.12. Automatic Ubuntu Installation Overview

Preconfiguration file method preseeding

fishy
  • Installation answers are stored in preseed.cfg file.

  • File preseed.cfg can be stored on URL, CD, HD, floppy.

  • Limitations by preseed.cfg config options.

  • Only one HD can be partitioned.

PXE boot, then restores from archived image on an NFS server.

fishy
  • Install OS then archive it (tar-gzip) onto NFS server.

  • PXE boot: gets IP from a DHCP, kernel and initrd from a TFTP server.

  • Partitions disks, mounts NFS, then restores the file system from the archive.

  • No need for Ubuntu mirror.

  • Needs custom initrd.

  • The OS may not be up-to-date after the installation.

Fully Automatic Installation FAI

fishy
  • Configure the installer root on the NFS server.

  • PXE boot: gets IP from a DHCP, kernel and initrd from a TFTP server.

  • Mounts the installer root from the NFS server.

  • Very customizable installation classes.

  • The installed OS is up-to date.

  • Takes time to learn FAI.


2.13. Purpose of Virtualization

In computing, a virtualization is the facility that allows multiple operating systems (VMs) to run simultaneously on a computer in a safe and efficient manner.

virtualization

Virtualization purposes:

  • Application development and testing on a separate system,

  • Server consolidation on one platform,

  • Virtual appliances (download a VM applience for specific application or service)

  • Prototyping and setting VMs to run on a remote server or/and cloud.

  • Multiple Operating systems on a desktop.


2.14. Virtualization with KVM

KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V).

KVM

Exercise To see if the processor supports hardware virtualization:

egrep -c '(vmx|svm)' /proc/cpuinfo

If 0 it means that your CPU doesn’t support hardware virtualization. If 1 or more it does - but you still need to make sure that virtualization is enabled in the BIOS.

Install package cpu-checker:
apt-get install cpu-checker

Verify that the kvm module is loaded into the kernel and the BIOS has virtualization enabled

kvm-ok

If it shows:
INFO: /dev/kvm does not exist
HINT: sudo modprobe kvm_intel
INFO: Your CPU supports KVM extensions
KVM acceleration can be used

Run commands:

modprobe kvm_intel
kvm-ok

You should see now:

INFO: Your CPU supports KVM extensions
INFO: /dev/kvm exists

KVM acceleration can be used

If it shows:

INFO: Your CPU supports KVM extensions
INFO: KVM is disabled by your BIOS

the Virtualization support needs to be enabled in the BIOS


2.15. Preparation for Ubuntu VM installation (Exercise)

Install KVM virtual director:

sudo -s
apt-get install virt-manager

Correct the ownership of the VM image directory:

chown hostadm:hostadm /var/lib/libvirt/images

Add user hostadm to group libvirt:

usermod -a -G libvirt hostadm

Install kvm packages:

apt-get install qemu-kvm qemu-system

Restart libvirtd service:

systemctl restart libvirtd 

Logout from the desktop, then login again. Create directory KVM within your home directory and download the installer, ubuntu-18.04.4-server-amd64.iso

mkdir KVM
cd KVM
wget http://cdimage.ubuntu.com/releases/18.04/release/ubuntu-18.04.5-server-amd64.iso

2.16. VM configuration in KVM manager (Exercise)

Launch the Virtual Machine manager: the Virtual Machine Manager will appear in Applications -> System Tools menu.
Click onto the top left icon to create a new virtual machine.

KVM director start


KVM director


2.17. Create a new virtual machine with the following parameters:

  • Name: kvm1

  • Local install media ISO

  • Use ISO image: /home/hostadm/KVM/ubuntu-18.04.5-server-amd64.iso

  • OS type: Linux

  • Version: 18.04

  • Memory (RAM): 512 MB

  • CPUs: 1

  • Disk image: 4.0 GB

  • Check in “Allocate entire disk now”

2.18. Ubuntu Interactive Installation (Exercise)

Click onto kvm1 in the KVM manager. It will bring up a virtual console for the VM with the installer running. After accepting ‘English Language’, press F4, which stands for “Modes” in the installer bottom menu line, and scroll down to “Install a minimal virtual machine” selection, press ENTER:

Choose “Install Ubuntu Server”, and press ENTER.

Choose language: English, United States. Choose ‘No’ for detecting keyboard layout, USA for the origin of the keyboard, USA for keyboard layout. In ‘Configure the network’ menu, set ‘kvm1’:

When the installer prompts you, set a new user account,

name: hostadm
passwd: unisys

Accept the “weak password” when prompted.

In ‘Configure the clock’, choose Eastern in the time zone list.

In the partition disks menu, select ‘Guided - use entire disk’ partitioning method.

Choose no encryption for home directory.

Select “No automatic updates”.

Do not select any additional software to install.

Keep everything in the list unchecked:

When prompted to Install the GRUB boot loader, choose the default option, “Install the GRUB boot loader to the master boot record” .

Accept setting the system clock to UTC.

Click on ‘continue’ when the installation completes.

After the system reboots, login as user hostadm

Install SSH server by using apt

sudo -s
apt-get install openssh-server

Install the latest 4.x Linux kernel available in Ubuntu 18.04 LTS repository:

apt-get update
apt-get install linux-virtual

Install editor nano. The editor is very intuitive to use. The detailed HOWTO can be found here (Links to an external site.)

apt-get install nano

Edit file /etc/default/grub

nano /etc/default/grub

and increase the GRUB prompt timeout from 2 to 10: GRUB_TIMEOUT=10:

GRUB_TIMEOUT=10

Change the value of GRUB_TIMEOUT_STYLE from hidden to menu

GRUB_TIMEOUT_STYLE=menu

Run the commands to update the boot loader configuration, then reboot:

update-grub
reboot

You should be able to see the boot loader prompt when the system boots up.

Login to kvm1 and make sure it is running the kernel you just have installed:

uname -a

It should show Linux kvm1 4.15.0-135-generic…

Uninstall the old kernel related packages:

apt-get remove linux-image-4.15.0-112-generic 
apt-get remove linux-headers-4.15.0-112
apt-get remove linux-modules-4.15.0-112-generic
update-grub

After you are done with the exercise, shutdown the virtual machine by issuing shutdown in its command prompt:

shutdown now -h

References: Ubuntu Installation Guide