KVM: Difference between revisions

Revision as of 23:38, 25 April 2019

KVM is an free and open source virtualization solution in a kernel module. Although it is often simply referred to as KVM, the actual hypervisor is QEMU. QEMU runs from user-space, but can integrate with KVM, providing better performance by leveraging the hardware from kernel-space. QEMU can virtualize x86, PowerPC, and S390 guests, amongst others. Libvirt is a management framework that integrates with QEMU/KVM, LXC, Xen and others.

Installation

The following commands provide libvirt as well as QEMU with emulation for x86_64 and qemu-img, a necessary component for using various disk formats such as qcow2. Without qemu-img, only raw disks are available. It can also convert images between several formats like vhdx and vmdk.

# apk add libvirt qemu-img qemu-system-x86_64 # rc-update add libvirtd

Networking

By default, libvirt uses NAT for VM connectivity. If you want to use the default configuration, you need to load the tun module.

# modprobe tun

If you prefer bridging a guest over your Ethernet interface, you need to make a bridge.

Management

For (non-root) management, you will need to add your user to the libvirt group.

# addgroup user libvirt

The libvirt project provides a GUI for managing hosts, called virt-manager. It handles local systems as well as remote ones via SSH.

# apk add dbus polkit virt-manager # rc-update add dbus

In order to use libvirtd to remotely control KVM over ssh PolicyKit needs a .pkla informing it that this is allowed. Write the following file to /etc/polkit-1/localauthority/50-local.d/50-libvirt-ssh-remote-access-policy.pkla

[Remote libvirt SSH access] Identity=unix-group:libvirt Action=org.libvirt.unix.manage ResultAny=yes ResultInactive=yes ResultActive=yes

@@ Line 1: / Line 1: @@
-[https://www.linux-kvm.org/page/Main_Page KVM] is an open source virtualization solution in a kernel module. KVM can virtualize x86, PowerPC, and S390 guests.
+[https://www.linux-kvm.org/page/Main_Page KVM] is an free and open source virtualization solution in a kernel module. Although it is often simply referred to as KVM, the actual hypervisor is [https://www.qemu.org QEMU]. QEMU runs from user-space, but can integrate with KVM, providing better performance by leveraging the hardware from kernel-space. QEMU can virtualize x86, PowerPC, and S390 guests, amongst others. [https://libvirt.org Libvirt] is a management framework that integrates with QEMU/KVM, [https://wiki.alpinelinux.org/wiki/LXC LXC], [https://wiki.alpinelinux.org/wiki/Xen_Dom0 Xen] and others.
-== Installing KVM ==
+== Installation ==
-It is possible to install just qemu and libvirt for local management
+The following commands provide '''libvirt''' as well as '''QEMU with emulation for x86_64''' and '''qemu-img''', a necessary component for using various disk formats such as qcow2. Without qemu-img, only raw disks are available. It can also convert images between several formats like vhdx and vmdk.
-{{Cmd|sudo apk add qemu-system-x86_64 libvirt}}
+{{Cmd|<nowiki># apk add libvirt qemu-img qemu-system-x86_64
-but most users will probably want to manage it via a GUI with virt-manager (remotely or not).
+# rc-update add libvirtd</nowiki>}}
-{{Cmd|sudo apk add libvirt-daemon dbus polkit}}
-If you want to use other disk image formats than raw, you need qemu-img
-{{Cmd|sudo apk add qemu-img}}
-Enable the KVM kernel module
+== Networking ==
-{{Cmd|sudo modprobe kvm-intel}}
+By default, libvirt uses NAT for VM connectivity. If you want to use the default configuration, you need to load the tun module.
-or
+{{Cmd|# modprobe tun}}
-{{Cmd|sudo modprobe kvm-amd}}
-=== Service start on boot ===
+If you prefer bridging a guest over your Ethernet interface, you need to make a [https://wiki.alpinelinux.org/wiki/Bridge#Configuration_file bridge].
-Set libvirtd and dbus to start on startup
-{{Cmd|sudo rc-update add libvirtd
-sudo rc-update add dbus}}
-== Networking ==
+== Management ==
-by defaults kvm use bridge to nat vm, if you want network with the default configuration, you need to load the tun module
+For (non-root) management, you will need to add your user to the libvirt group.
-{{Cmd|sudo modprobe tun}}
+{{Cmd|# addgroup user libvirt}}
-but if you prefer bridging kvm over your ethernet interface, you need to make a [https://wiki.alpinelinux.org/wiki/Bridge#Configuration_file bridge]
-== Groups and user ==
+The libvirt project provides a GUI for managing hosts, called virt-manager. It handles local systems as well as remote ones via SSH.
-Add your user to the follwing groups so you can mange the vms
+{{Cmd|<nowiki># apk add dbus polkit virt-manager
-{{Cmd|sudo addgroup user libvirt}}
+# rc-update add dbus</nowiki>}}
-=== PolicyKit for Remote User ===
 In order to use libvirtd to remotely control KVM over ssh PolicyKit needs a .pkla informing it that this is allowed.
 Write the following file to /etc/polkit-1/localauthority/50-local.d/50-libvirt-ssh-remote-access-policy.pkla