 1ce6b05ea1
			
		
	
	
		1ce6b05ea1
		
	
	
	
	
		
			
			At the moment, it's not possible to override the libvirtd package used without supplying a nixpkgs overlay. Adding a package option makes libvirtd more consistent and allows enabling e.g. ceph and iSCSI support more easily.
		
			
				
	
	
		
			290 lines
		
	
	
		
			9.0 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			290 lines
		
	
	
		
			9.0 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.qemuOvmf ''
 | |
|       nvram = ["/run/libvirt/nix-ovmf/OVMF_CODE.fd:/run/libvirt/nix-ovmf/OVMF_VARS.fd"]
 | |
|     ''}
 | |
|     ${optionalString (!cfg.qemuRunAsRoot) ''
 | |
|       user = "qemu-libvirtd"
 | |
|       group = "qemu-libvirtd"
 | |
|     ''}
 | |
|     ${cfg.qemuVerbatimConfig}
 | |
|   '';
 | |
|   dirName = "libvirt";
 | |
|   subDirs = list: [ dirName ] ++ map (e: "${dirName}/${e}") list;
 | |
| 
 | |
| in {
 | |
| 
 | |
|   imports = [
 | |
|     (mkRemovedOptionModule [ "virtualisation" "libvirtd" "enableKVM" ]
 | |
|       "Set the option `virtualisation.libvirtd.qemuPackage' instead.")
 | |
|   ];
 | |
| 
 | |
|   ###### interface
 | |
| 
 | |
|   options.virtualisation.libvirtd = {
 | |
| 
 | |
|     enable = mkOption {
 | |
|       type = types.bool;
 | |
|       default = false;
 | |
|       description = ''
 | |
|         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> command line tool, among others.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     package = mkOption {
 | |
|       type = types.package;
 | |
|       default = pkgs.libvirt;
 | |
|       defaultText = "pkgs.libvirt";
 | |
|       description = ''
 | |
|         libvirt package to use.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     qemuPackage = mkOption {
 | |
|       type = types.package;
 | |
|       default = pkgs.qemu;
 | |
|       description = ''
 | |
|         Qemu package to use with libvirt.
 | |
|         `pkgs.qemu` can emulate alien architectures (e.g. aarch64 on x86)
 | |
|         `pkgs.qemu_kvm` saves disk space allowing to emulate only host architectures.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     extraConfig = mkOption {
 | |
|       type = types.lines;
 | |
|       default = "";
 | |
|       description = ''
 | |
|         Extra contents appended to the libvirtd configuration file,
 | |
|         libvirtd.conf.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     qemuRunAsRoot = mkOption {
 | |
|       type = types.bool;
 | |
|       default = true;
 | |
|       description = ''
 | |
|         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.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     qemuVerbatimConfig = mkOption {
 | |
|       type = types.lines;
 | |
|       default = ''
 | |
|         namespaces = []
 | |
|       '';
 | |
|       description = ''
 | |
|         Contents written to the qemu configuration file, qemu.conf.
 | |
|         Make sure to include a proper namespace configuration when
 | |
|         supplying custom configuration.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     qemuOvmf = mkOption {
 | |
|       type = types.bool;
 | |
|       default = true;
 | |
|       description = ''
 | |
|         Allows libvirtd to take advantage of OVMF when creating new
 | |
|         QEMU VMs with UEFI boot.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     extraOptions = mkOption {
 | |
|       type = types.listOf types.str;
 | |
|       default = [ ];
 | |
|       example = [ "--verbose" ];
 | |
|       description = ''
 | |
|         Extra command line arguments passed to libvirtd on startup.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     onBoot = mkOption {
 | |
|       type = types.enum ["start" "ignore" ];
 | |
|       default = "start";
 | |
|       description = ''
 | |
|         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 = ''
 | |
|         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.
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|     allowedBridges = mkOption {
 | |
|       type = types.listOf types.str;
 | |
|       default = [ "virbr0" ];
 | |
|       description = ''
 | |
|         List of bridge devices that can be used by qemu:///session
 | |
|       '';
 | |
|     };
 | |
| 
 | |
|   };
 | |
| 
 | |
| 
 | |
|   ###### implementation
 | |
| 
 | |
|   config = mkIf cfg.enable {
 | |
| 
 | |
|     environment = {
 | |
|       # this file is expected in /etc/qemu and not sysconfdir (/var/lib)
 | |
|       etc."qemu/bridge.conf".text = lib.concatMapStringsSep "\n" (e:
 | |
|         "allow ${e}") cfg.allowedBridges;
 | |
|       systemPackages = with pkgs; [ libressl.nc iptables cfg.package cfg.qemuPackage ];
 | |
|       etc.ethertypes.source = "${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 = {
 | |
|       source = "/run/${dirName}/nix-helpers/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 ${cfg.package}/var/lib && echo \
 | |
|             libvirt/qemu/networks/*.xml libvirt/qemu/networks/autostart/*.xml \
 | |
|             libvirt/nwfilter/*.xml );
 | |
|         do
 | |
|             mkdir -p /var/lib/$(dirname $i) -m 755
 | |
|             cp -npd ${cfg.package}/var/lib/$i /var/lib/$i
 | |
|         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.qemuPackage}/bin/qemu-kvm ${cfg.qemuPackage}/bin/qemu-system-*; do
 | |
|           ln -s --force "$emulator" /run/${dirName}/nix-emulators/
 | |
|         done
 | |
| 
 | |
|         for helper in libexec/qemu-bridge-helper bin/qemu-pr-helper; do
 | |
|           ln -s --force ${cfg.qemuPackage}/$helper /run/${dirName}/nix-helpers/
 | |
|         done
 | |
| 
 | |
|         ${optionalString cfg.qemuOvmf ''
 | |
|           ln -s --force ${pkgs.OVMF.fd}/FV/OVMF_CODE.fd /run/${dirName}/nix-ovmf/
 | |
|           ln -s --force ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd /run/${dirName}/nix-ovmf/
 | |
|         ''}
 | |
|       '';
 | |
| 
 | |
|       serviceConfig = {
 | |
|         Type = "oneshot";
 | |
|         RuntimeDirectoryPreserve = "yes";
 | |
|         LogsDirectory = subDirs [ "qemu" ];
 | |
|         RuntimeDirectory = subDirs [ "nix-emulators" "nix-helpers" "nix-ovmf" ];
 | |
|         StateDirectory = subDirs [ "dnsmasq" ];
 | |
|       };
 | |
|     };
 | |
| 
 | |
|     systemd.services.libvirtd = {
 | |
|       requires = [ "libvirtd-config.service" ];
 | |
|       after = [ "libvirtd-config.service" ]
 | |
|               ++ optional vswitch.enable "ovs-vswitchd.service";
 | |
| 
 | |
|       environment.LIBVIRTD_ARGS = escapeShellArgs (
 | |
|         [ "--config" configFile
 | |
|           "--timeout" "120"     # from ${libvirt}/var/lib/sysconfig/libvirtd
 | |
|         ] ++ cfg.extraOptions);
 | |
| 
 | |
|       path = [ cfg.qemuPackage ] # libvirtd requires qemu-img to manage disk images
 | |
|              ++ optional vswitch.enable vswitch.package;
 | |
| 
 | |
|       serviceConfig = {
 | |
|         Type = "notify";
 | |
|         KillMode = "process"; # when stopping, leave the VMs alone
 | |
|         Restart = "no";
 | |
|       };
 | |
|       restartIfChanged = false;
 | |
|     };
 | |
| 
 | |
|     systemd.services.libvirt-guests = {
 | |
|       wantedBy = [ "multi-user.target" ];
 | |
|       path = with pkgs; [ coreutils gawk cfg.package ];
 | |
|       restartIfChanged = false;
 | |
| 
 | |
|       environment.ON_BOOT = "${cfg.onBoot}";
 | |
|       environment.ON_SHUTDOWN = "${cfg.onShutdown}";
 | |
|     };
 | |
| 
 | |
|     systemd.sockets.virtlogd = {
 | |
|       description = "Virtual machine log manager socket";
 | |
|       wantedBy = [ "sockets.target" ];
 | |
|       listenStreams = [ "/run/${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" ];
 | |
| 
 | |
|     security.polkit.extraConfig = ''
 | |
|       polkit.addRule(function(action, subject) {
 | |
|         if (action.id == "org.libvirt.unix.manage" &&
 | |
|           subject.isInGroup("libvirtd")) {
 | |
|           return polkit.Result.YES;
 | |
|         }
 | |
|       });
 | |
|     '';
 | |
|   };
 | |
| }
 |