Linux Professional Institute Certification I



Chapter 5 Booting, Initializing, and Virtualizing Linux

Sommaire

  • Understanding the Boot Process
  • Looking at Firmware
  • Looking at Boot Loaders
  • The Initialization Process
  • Using the systemd Initialization Process
  • Using the SysV Initialization Process
  • Stopping the System
  • Notifying the Users
  • Virtualizing Linux

Understanding the Boot Process

Booting Steps

  1. Au boot le BIOS exécute le MBR (Master Boot Record) situé sur le premier secteur (512 octets) du support bootable choisi (disque, CD, clef USB, ...)
  2. Le MBR scanne le disque pour trouver la partition bootable (flag)
  3. Le MBR lance le boot loader (chargeur de démarrage) du secteur de boot (premier secteur) de la partition bootable
  4. Le bootloader charge le noyau en mémoire et l'exécute
  5. Le bootloader charge le ramdisk initrd.img en mémoire
  6. 2 bootloader possibles:
    - Lilo (Linux Loader)
    - Grub (Grand Unified Bootloader)
  7. Une fois le noyau chargé en mémoire, il lance le premier processus /bin/init
  8. init est le père de tous les autres processus qui seront créés par l'appel system fork()
  9. init lit le fichier /etc/inittab pour savoir :
    - quel est le fichier à exécuter pour continuer le chargement du système
    - quel est le runlevel (niveau d'exécution) par défault
    - comment lancer les services pour un runlevel donné

Looking at Firmware

Looking at Boot Loaders

The Initialization Process

Using the systemd Initialization Process

Using the SysV Initialization Process

Stopping the System

Notifying the Users

Virtualizing Linux

Virtualization

Goal

To create and use Red Hat Enterprise Linux virtual machines with Kernel-based Virtual Machine (KVM) and libvirt.

Red Hat’s default virtual machine (VM) solution,
the Kernel-based Virtual Machine (KVM)

Before installing Red Hat Enterprise Linux (RHEL), you need the right hardware.
You’ll need to have a physical system with a 64-bit CPU capable of hardware Virtualization

Qemu= virtualization emulator = red hat hypervisor
KVM= software which use qemu

If you want to know if your machine support virtualization open /proc/cpuinfo if you see flags:vmx,svm then your machine support virtualization Vmx (intel) svm (AMD)

Files and directories

/var/lib/libvirt
/var/lib/libvirt/images/ default directory to save virtual OS images
/etc/init.d/libvirtd virtualisation service
/etc/libvirt/qemu
/etc/libvirt/qemu/networks/….xml virtual network config file

Managing VMs

virt-manager open GUI VM manager
virt-install

virt-install [+]
virsh [+]

Kernel-based Virtual Machine (KVM)

Installation

Essentials Packages
qemu-kvm KVM principal package
python-virtinst command line tools and libraries for VMs creation
virt-manager GUI VM administration tool
virt-top VMs statistics commands
virt-viewer graphical connection to configured Vms
libvirt C language tools with libvirtd service
libvirt-client C language toolkit for VM clients

Principals Packages to install
qemu-kvm modules de virtualization, hypervisor
virt-manager VMs GUI manager
libvirt libvirtd service package

To create and use Red Hat Enterprise Linux virtual machines with Kernel-based Virtual Machine (KVM) and libvirt. Red Hat’s default virtual machine (VM) solution, the Kernel-based Virtual Machine (KVM) Before installing Red Hat Enterprise Linux (RHEL), you need the right hardware. You’ll need to have a physical system with a 64-bit CPU capable of hardware Virtualization Qemu= virtualization emulator = red hat hypervisor KVM= software which use qemu If youwant to know if your machine support virtualization open /proc/cpuinfo if you see flags:vmx,svm then your machine support virtualization Vmx (intel) svm (AMD) Necessary Packages qemu-kvm KVM principal package python-virtinst command line tools and libraries for VMs creation virt-manager GUI VM administration tool virt-top VMs statistics commands virt-viewer graphical connection to configured Vms libvirt C language tools with libvirtd service libvirt-client C language toolkit for VM clients Principals Packages to install qemu-kvm modules de virtualization, hypervisor virt-manager VMs GUI manager libvirt libvirtd service package Important files and directories /var/lib/libvirt /var/lib/libvirt/images/ default directory to save virtual OS images /etc/init.d/libvirtd virtualisation service /etc/libvirt/qemu /etc/libvirt/qemu/networks/….xml virtual network config file Commands virt-manager open GUI VM manager virt-install - -prompt install OS in interactive style virt-install options -n machine name -r RAM capacity in MB - - disk path= image path size= size in Go -l OS source -x extra arguments file virsh Options list- - all show all machines status autostart machinename start VM at host boot autostart -disable machinename deactivate VM autostart at host boot start machinename start VM shutdown machinename destroy machinename force machine stop
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