nixpkgs/nixos/modules/virtualisation/libvirtd.nix

542 lines
17 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.virtualisation.libvirtd;
vswitch = config.virtualisation.vswitch;
configFile = pkgs.writeText "libvirtd.conf" ''
auth_unix_ro = "polkit"
auth_unix_rw = "polkit"
${cfg.extraConfig}
'';
qemuConfigFile = pkgs.writeText "qemu.conf" ''
${optionalString cfg.qemu.ovmf.enable ''
nvram = [ "/run/libvirt/nix-ovmf/AAVMF_CODE.fd:/run/libvirt/nix-ovmf/AAVMF_VARS.fd", "/run/libvirt/nix-ovmf/OVMF_CODE.fd:/run/libvirt/nix-ovmf/OVMF_VARS.fd" ]
''}
${optionalString (!cfg.qemu.runAsRoot) ''
user = "qemu-libvirtd"
group = "qemu-libvirtd"
''}
${cfg.qemu.verbatimConfig}
'';
dirName = "libvirt";
subDirs = list: [ dirName ] ++ map (e: "${dirName}/${e}") list;
ovmfModule = types.submodule {
options = {
enable = mkOption {
type = types.bool;
default = true;
description = lib.mdDoc ''
Allows libvirtd to take advantage of OVMF when creating new
QEMU VMs with UEFI boot.
'';
};
# mkRemovedOptionModule does not work in submodules, do it manually
package = mkOption {
type = types.nullOr types.package;
default = null;
internal = true;
};
packages = mkOption {
type = types.listOf types.package;
default = [ pkgs.OVMF.fd ];
defaultText = literalExpression "[ pkgs.OVMF.fd ]";
example = literalExpression "[ pkgs.OVMFFull.fd pkgs.pkgsCross.aarch64-multiplatform.OVMF.fd ]";
description = lib.mdDoc ''
List of OVMF packages to use. Each listed package must contain files names FV/OVMF_CODE.fd and FV/OVMF_VARS.fd or FV/AAVMF_CODE.fd and FV/AAVMF_VARS.fd
'';
};
};
};
swtpmModule = types.submodule {
options = {
enable = mkOption {
type = types.bool;
default = false;
description = lib.mdDoc ''
Allows libvirtd to use swtpm to create an emulated TPM.
'';
};
package = mkPackageOption pkgs "swtpm" { };
};
};
qemuModule = types.submodule {
options = {
package = mkPackageOption pkgs "qemu" {
extraDescription = ''
`pkgs.qemu` can emulate alien architectures (e.g. aarch64 on x86)
`pkgs.qemu_kvm` saves disk space allowing to emulate only host architectures.
'';
};
runAsRoot = mkOption {
type = types.bool;
default = true;
description = lib.mdDoc ''
If true, libvirtd runs qemu as root.
If false, libvirtd runs qemu as unprivileged user qemu-libvirtd.
Changing this option to false may cause file permission issues
for existing guests. To fix these, manually change ownership
of affected files in /var/lib/libvirt/qemu to qemu-libvirtd.
'';
};
verbatimConfig = mkOption {
type = types.lines;
default = ''
namespaces = []
'';
description = lib.mdDoc ''
Contents written to the qemu configuration file, qemu.conf.
Make sure to include a proper namespace configuration when
supplying custom configuration.
'';
};
ovmf = mkOption {
type = ovmfModule;
default = { };
description = lib.mdDoc ''
QEMU's OVMF options.
'';
};
swtpm = mkOption {
type = swtpmModule;
default = { };
description = lib.mdDoc ''
QEMU's swtpm options.
'';
};
vhostUserPackages = mkOption {
type = types.listOf types.package;
default = [ ];
example = lib.literalExpression "[ pkgs.virtiofsd ]";
description = lib.mdDoc ''
Packages containing out-of-tree vhost-user drivers.
'';
};
};
};
hooksModule = types.submodule {
options = {
daemon = mkOption {
type = types.attrsOf types.path;
default = { };
description = lib.mdDoc ''
Hooks that will be placed under /var/lib/libvirt/hooks/daemon.d/
and called for daemon start/shutdown/SIGHUP events.
Please see https://libvirt.org/hooks.html for documentation.
'';
};
qemu = mkOption {
type = types.attrsOf types.path;
default = { };
description = lib.mdDoc ''
Hooks that will be placed under /var/lib/libvirt/hooks/qemu.d/
and called for qemu domains begin/end/migrate events.
Please see https://libvirt.org/hooks.html for documentation.
'';
};
lxc = mkOption {
type = types.attrsOf types.path;
default = { };
description = lib.mdDoc ''
Hooks that will be placed under /var/lib/libvirt/hooks/lxc.d/
and called for lxc domains begin/end events.
Please see https://libvirt.org/hooks.html for documentation.
'';
};
libxl = mkOption {
type = types.attrsOf types.path;
default = { };
description = lib.mdDoc ''
Hooks that will be placed under /var/lib/libvirt/hooks/libxl.d/
and called for libxl-handled xen domains begin/end events.
Please see https://libvirt.org/hooks.html for documentation.
'';
};
network = mkOption {
type = types.attrsOf types.path;
default = { };
description = lib.mdDoc ''
Hooks that will be placed under /var/lib/libvirt/hooks/lxc.d/
and called for networks begin/end events.
Please see https://libvirt.org/hooks.html for documentation.
'';
};
};
};
nssModule = types.submodule {
options = {
enable = mkOption {
type = types.bool;
default = false;
description = lib.mdDoc ''
This option enables the older libvirt NSS module. This method uses
DHCP server records, therefore is dependent on the hostname provided
by the guest.
Please see https://libvirt.org/nss.html for more information.
'';
};
enableGuest = mkOption {
type = types.bool;
default = false;
description = lib.mdDoc ''
This option enables the newer libvirt_guest NSS module. This module
uses the libvirt guest name instead of the hostname of the guest.
Please see https://libvirt.org/nss.html for more information.
'';
};
};
};
in
{
imports = [
(mkRemovedOptionModule [ "virtualisation" "libvirtd" "enableKVM" ]
"Set the option `virtualisation.libvirtd.qemu.package' instead.")
(mkRenamedOptionModule
[ "virtualisation" "libvirtd" "qemuPackage" ]
[ "virtualisation" "libvirtd" "qemu" "package" ])
(mkRenamedOptionModule
[ "virtualisation" "libvirtd" "qemuRunAsRoot" ]
[ "virtualisation" "libvirtd" "qemu" "runAsRoot" ])
(mkRenamedOptionModule
[ "virtualisation" "libvirtd" "qemuVerbatimConfig" ]
[ "virtualisation" "libvirtd" "qemu" "verbatimConfig" ])
(mkRenamedOptionModule
[ "virtualisation" "libvirtd" "qemuOvmf" ]
[ "virtualisation" "libvirtd" "qemu" "ovmf" "enable" ])
(mkRemovedOptionModule
[ "virtualisation" "libvirtd" "qemuOvmfPackage" ]
"If this option was set to `foo`, set the option `virtualisation.libvirtd.qemu.ovmf.packages' to `[foo.fd]` instead.")
(mkRenamedOptionModule
[ "virtualisation" "libvirtd" "qemuSwtpm" ]
[ "virtualisation" "libvirtd" "qemu" "swtpm" "enable" ])
];
###### interface
options.virtualisation.libvirtd = {
enable = mkOption {
type = types.bool;
default = false;
description = lib.mdDoc ''
This option enables libvirtd, a daemon that manages
virtual machines. Users in the "libvirtd" group can interact with
the daemon (e.g. to start or stop VMs) using the
{command}`virsh` command line tool, among others.
'';
};
package = mkPackageOption pkgs "libvirt" { };
extraConfig = mkOption {
type = types.lines;
default = "";
description = lib.mdDoc ''
Extra contents appended to the libvirtd configuration file,
libvirtd.conf.
'';
};
extraOptions = mkOption {
type = types.listOf types.str;
default = [ ];
example = [ "--verbose" ];
description = lib.mdDoc ''
Extra command line arguments passed to libvirtd on startup.
'';
};
onBoot = mkOption {
type = types.enum [ "start" "ignore" ];
default = "start";
description = lib.mdDoc ''
Specifies the action to be done to / on the guests when the host boots.
The "start" option starts all guests that were running prior to shutdown
regardless of their autostart settings. The "ignore" option will not
start the formerly running guest on boot. However, any guest marked as
autostart will still be automatically started by libvirtd.
'';
};
onShutdown = mkOption {
type = types.enum [ "shutdown" "suspend" ];
default = "suspend";
description = lib.mdDoc ''
When shutting down / restarting the host what method should
be used to gracefully halt the guests. Setting to "shutdown"
will cause an ACPI shutdown of each guest. "suspend" will
attempt to save the state of the guests ready to restore on boot.
'';
};
parallelShutdown = mkOption {
type = types.ints.unsigned;
default = 0;
description = lib.mdDoc ''
Number of guests that will be shutdown concurrently, taking effect when onShutdown
is set to "shutdown". If set to 0, guests will be shutdown one after another.
Number of guests on shutdown at any time will not exceed number set in this
variable.
'';
};
allowedBridges = mkOption {
type = types.listOf types.str;
default = [ "virbr0" ];
description = lib.mdDoc ''
List of bridge devices that can be used by qemu:///session
'';
};
qemu = mkOption {
type = qemuModule;
default = { };
description = lib.mdDoc ''
QEMU related options.
'';
};
hooks = mkOption {
type = hooksModule;
default = { };
description = lib.mdDoc ''
Hooks related options.
'';
};
nss = mkOption {
type = nssModule;
default = { };
description = lib.mdDoc ''
libvirt NSS module options.
'';
};
};
###### implementation
config = mkIf cfg.enable {
assertions = [
{
assertion = config.virtualisation.libvirtd.qemu.ovmf.package == null;
message = ''
The option virtualisation.libvirtd.qemu.ovmf.package is superseded by virtualisation.libvirtd.qemu.ovmf.packages.
If this option was set to `foo`, set the option `virtualisation.libvirtd.qemu.ovmf.packages' to `[foo.fd]` instead.
'';
}
{
assertion = config.security.polkit.enable;
message = "The libvirtd module currently requires Polkit to be enabled ('security.polkit.enable = true').";
}
];
environment = {
# this file is expected in /etc/qemu and not sysconfdir (/var/lib)
etc."qemu/bridge.conf".text = lib.concatMapStringsSep "\n"
(e:
"allow ${e}")
cfg.allowedBridges;
systemPackages = with pkgs; [ libressl.nc iptables cfg.package cfg.qemu.package ];
etc.ethertypes.source = "${pkgs.iptables}/etc/ethertypes";
};
boot.kernelModules = [ "tun" ];
users.groups.libvirtd.gid = config.ids.gids.libvirtd;
# libvirtd runs qemu as this user and group by default
users.extraGroups.qemu-libvirtd.gid = config.ids.gids.qemu-libvirtd;
users.extraUsers.qemu-libvirtd = {
uid = config.ids.uids.qemu-libvirtd;
isNormalUser = false;
group = "qemu-libvirtd";
};
security.wrappers.qemu-bridge-helper = {
setuid = true;
owner = "root";
group = "root";
source = "${cfg.qemu.package}/libexec/qemu-bridge-helper";
};
systemd.packages = [ cfg.package ];
systemd.services.libvirtd-config = {
description = "Libvirt Virtual Machine Management Daemon - configuration";
script = ''
# Copy default libvirt network config .xml files to /var/lib
# Files modified by the user will not be overwritten
for i in $(cd ${cfg.package}/var/lib && echo \
libvirt/qemu/networks/*.xml \
libvirt/nwfilter/*.xml );
do
mkdir -p /var/lib/$(dirname $i) -m 755
if [ ! -e /var/lib/$i ]; then
cp -pd ${cfg.package}/var/lib/$i /var/lib/$i
fi
done
# Copy generated qemu config to libvirt directory
cp -f ${qemuConfigFile} /var/lib/${dirName}/qemu.conf
# stable (not GC'able as in /nix/store) paths for using in <emulator> section of xml configs
for emulator in ${cfg.package}/libexec/libvirt_lxc ${cfg.qemu.package}/bin/qemu-kvm ${cfg.qemu.package}/bin/qemu-system-*; do
ln -s --force "$emulator" /run/${dirName}/nix-emulators/
done
for helper in bin/qemu-pr-helper; do
ln -s --force ${cfg.qemu.package}/$helper /run/${dirName}/nix-helpers/
done
${optionalString cfg.qemu.ovmf.enable (let
ovmfpackage = pkgs.buildEnv {
name = "qemu-ovmf";
paths = cfg.qemu.ovmf.packages;
};
in
''
ln -s --force ${ovmfpackage}/FV/AAVMF_CODE.fd /run/${dirName}/nix-ovmf/
ln -s --force ${ovmfpackage}/FV/OVMF_CODE.fd /run/${dirName}/nix-ovmf/
ln -s --force ${ovmfpackage}/FV/AAVMF_VARS.fd /run/${dirName}/nix-ovmf/
ln -s --force ${ovmfpackage}/FV/OVMF_VARS.fd /run/${dirName}/nix-ovmf/
'')}
# Symlink hooks to /var/lib/libvirt
${concatStringsSep "\n" (map (driver:
''
mkdir -p /var/lib/${dirName}/hooks/${driver}.d
rm -rf /var/lib/${dirName}/hooks/${driver}.d/*
${concatStringsSep "\n" (mapAttrsToList (name: value:
"ln -s --force ${value} /var/lib/${dirName}/hooks/${driver}.d/${name}") cfg.hooks.${driver})}
'') (attrNames cfg.hooks))}
'';
serviceConfig = {
Type = "oneshot";
RuntimeDirectoryPreserve = "yes";
LogsDirectory = subDirs [ "qemu" ];
RuntimeDirectory = subDirs [ "nix-emulators" "nix-helpers" "nix-ovmf" ];
StateDirectory = subDirs [ "dnsmasq" ];
};
};
systemd.services.libvirtd = {
wantedBy = [ "multi-user.target" ];
requires = [ "libvirtd-config.service" ];
after = [ "libvirtd-config.service" ]
++ optional vswitch.enable "ovs-vswitchd.service";
environment.LIBVIRTD_ARGS = escapeShellArgs (
[
"--config"
configFile
"--timeout"
"120" # from ${libvirt}/var/lib/sysconfig/libvirtd
] ++ cfg.extraOptions
);
path = [ cfg.qemu.package pkgs.netcat ] # libvirtd requires qemu-img to manage disk images
++ optional vswitch.enable vswitch.package
++ optional cfg.qemu.swtpm.enable cfg.qemu.swtpm.package;
serviceConfig = {
Type = "notify";
KillMode = "process"; # when stopping, leave the VMs alone
Restart = "no";
OOMScoreAdjust = "-999";
};
restartIfChanged = false;
};
systemd.services.virtchd = {
path = [ pkgs.cloud-hypervisor ];
};
systemd.services.libvirt-guests = {
wantedBy = [ "multi-user.target" ];
path = with pkgs; [ coreutils gawk cfg.package ];
restartIfChanged = false;
environment.ON_BOOT = "${cfg.onBoot}";
environment.ON_SHUTDOWN = "${cfg.onShutdown}";
environment.PARALLEL_SHUTDOWN = "${toString cfg.parallelShutdown}";
};
systemd.sockets.virtlogd = {
description = "Virtual machine log manager socket";
wantedBy = [ "sockets.target" ];
listenStreams = [ "/run/${dirName}/virtlogd-sock" ];
};
systemd.services.virtlogd = {
description = "Virtual machine log manager";
serviceConfig.ExecStart = "@${cfg.package}/sbin/virtlogd virtlogd";
restartIfChanged = false;
};
systemd.sockets.virtlockd = {
description = "Virtual machine lock manager socket";
wantedBy = [ "sockets.target" ];
listenStreams = [ "/run/${dirName}/virtlockd-sock" ];
};
systemd.services.virtlockd = {
description = "Virtual machine lock manager";
serviceConfig.ExecStart = "@${cfg.package}/sbin/virtlockd virtlockd";
restartIfChanged = false;
};
# https://libvirt.org/daemons.html#monolithic-systemd-integration
systemd.sockets.libvirtd.wantedBy = [ "sockets.target" ];
systemd.tmpfiles.rules = let
vhostUserCollection = pkgs.buildEnv {
name = "vhost-user";
paths = cfg.qemu.vhostUserPackages;
pathsToLink = [ "/share/qemu/vhost-user" ];
};
in [ "L+ /var/lib/qemu/vhost-user - - - - ${vhostUserCollection}/share/qemu/vhost-user" ];
security.polkit = {
enable = true;
extraConfig = ''
polkit.addRule(function(action, subject) {
if (action.id == "org.libvirt.unix.manage" &&
subject.isInGroup("libvirtd")) {
return polkit.Result.YES;
}
});
'';
};
system.nssModules = optional (cfg.nss.enable or cfg.nss.enableGuest) cfg.package;
system.nssDatabases.hosts = builtins.concatLists [
(optional cfg.nss.enable "libvirt")
(optional cfg.nss.enableGuest "libvirt_guest")
];
};
}