Revision as of 16:33, 22 June 2018

Introduction

hypervisor

A hypervisor or virtual machine monitor (VMM) is computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine. The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems. Multiple instances of a variety of operating systems may share the virtualized hardware resources

• Type 1 hypervisor: hypervisors run directly on the system hardware – A “bare metal” embedded hypervisor,
• Type 2 hypervisor: hypervisors run on a host operating system that provides virtualization services, such as I/O device support and memory management.

KVM

Kernel-based Virtual Machine (KVM) is a virtualization infrastructure for the Linux kernel that turns it into a hypervisor. It was merged into the Linux kernel mainline in kernel version 2.6.20, which was released on February 5, 2007.KVM requires a processor with hardware virtualization extensions.

libvirt

libvirt is an open-source API, daemon and management tool for managing platform virtualization.[3] It can be used to manage KVM, Xen, VMware ESX, QEMU and other virtualization technologies. These APIs are widely used in the orchestration layer of hypervisors in the development of a cloud-based solution.

Virtual Machine Manager (app)

The virt-manager application is a desktop user interface for managing virtual machines through libvirt. It primarily targets KVM VMs, but also manages Xen and LXC (linux containers). It presents a summary view of running domains, their live performance & resource utilization statistics. Wizards enable the creation of new domains, and configuration & adjustment of a domain’s resource allocation & virtual hardware. An embedded VNC and SPICE client viewer presents a full graphical console to the guest domain.

Manage KVM

Manage networks

List all

# virsh net-list
 Name                 State      Autostart     Persistent
----------------------------------------------------------
 default              active     yes           yes
 docker-machines      active     yes           yes

# virsh net-info default
Name:           default
UUID:           3eb5cb82-b9ea-4a6e-8e54-1efea603f90c
Active:         yes
Persistent:     yes
Autostart:      yes
Bridge:         virbr0

Start networks

# virsh net-autostart default
# virsh net-start default

Add new network

Create the network description file:

<network>
  <name>default</name>
  <bridge name="virbr0"/>
  <forward mode="nat"/>
  <ip address="192.168.122.1" netmask="255.255.255.0">
    <dhcp>
      <range start="192.168.122.2" end="192.168.122.254"/>
    </dhcp>
  </ip>
</network>

Add the new network based on the new file:

# virsh net-define /tmp/default.xml
# virsh net-start default
# virsh net-autostart default