292 lines
8.7 KiB
Nix
292 lines
8.7 KiB
Nix
# Xen hypervisor (Dom0) support.
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{ config, lib, pkgs, ... }:
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with lib;
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let
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cfg = config.virtualisation.xen;
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xen = pkgs.xen;
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in
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{
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###### interface
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options = {
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virtualisation.xen.enable =
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mkOption {
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default = false;
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description =
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''
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Setting this option enables the Xen hypervisor, a
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virtualisation technology that allows multiple virtual
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machines, known as <emphasis>domains</emphasis>, to run
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concurrently on the physical machine. NixOS runs as the
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privileged <emphasis>Domain 0</emphasis>. This option
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requires a reboot to take effect.
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'';
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};
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virtualisation.xen.bootParams =
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mkOption {
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default = "";
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description =
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''
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Parameters passed to the Xen hypervisor at boot time.
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'';
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};
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virtualisation.xen.domain0MemorySize =
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mkOption {
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default = 0;
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example = 512;
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description =
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''
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Amount of memory (in MiB) allocated to Domain 0 on boot.
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If set to 0, all memory is assigned to Domain 0.
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'';
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};
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virtualisation.xen.bridge =
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mkOption {
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default = "xenbr0";
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description =
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''
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Create a bridge for the Xen domUs to connect to.
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'';
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};
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virtualisation.xen.stored =
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mkOption {
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type = types.path;
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description =
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''
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Xen Store daemon to use. Defaults to oxenstored of the xen package.
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'';
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};
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virtualisation.xen.trace =
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mkOption {
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default = false;
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description =
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''
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Enable Xen tracing.
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'';
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};
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};
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###### implementation
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config = mkIf cfg.enable {
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assertions = [ {
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assertion = pkgs.stdenv.isx86_64;
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message = "Xen currently not supported on ${pkgs.stdenv.system}";
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} {
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assertion = config.boot.loader.grub.enable && (config.boot.loader.grub.efiSupport == false);
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message = "Xen currently does not support EFI boot";
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} ];
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virtualisation.xen.stored = mkDefault "${xen}/bin/oxenstored";
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environment.systemPackages = [ xen ];
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# Make sure Domain 0 gets the required configuration
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#boot.kernelPackages = pkgs.boot.kernelPackages.override { features={xen_dom0=true;}; };
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boot.kernelModules =
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[ "xen-evtchn" "xen-gntdev" "xen-gntalloc" "xen-blkback" "xen-netback"
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"xen-pciback" "evtchn" "gntdev" "netbk" "blkbk" "xen-scsibk"
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"usbbk" "pciback" "xen-acpi-processor" "blktap2" "tun" "netxen_nic"
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"xen_wdt" "xen-acpi-processor" "xen-privcmd" "xen-scsiback"
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"xenfs"
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];
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# The radeonfb kernel module causes the screen to go black as soon
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# as it's loaded, so don't load it.
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boot.blacklistedKernelModules = [ "radeonfb" ];
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# Increase the number of loopback devices from the default (8),
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# which is way too small because every VM virtual disk requires a
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# loopback device.
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boot.extraModprobeConfig =
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''
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options loop max_loop=64
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'';
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virtualisation.xen.bootParams = [] ++
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optionals cfg.trace [ "loglvl=all" "guest_loglvl=all" ] ++
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optional (cfg.domain0MemorySize != 0) "dom0_mem=${toString cfg.domain0MemorySize}M";
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system.extraSystemBuilderCmds =
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''
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ln -s ${xen}/boot/xen.gz $out/xen.gz
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echo "${toString cfg.bootParams}" > $out/xen-params
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'';
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# Mount the /proc/xen pseudo-filesystem.
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system.activationScripts.xen =
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''
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if [ -d /proc/xen ]; then
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${pkgs.kmod}/bin/modprobe xenfs 2> /dev/null
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${pkgs.utillinux}/bin/mountpoint -q /proc/xen || \
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${pkgs.utillinux}/bin/mount -t xenfs none /proc/xen
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fi
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'';
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# Domain 0 requires a pvops-enabled kernel.
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system.requiredKernelConfig = with config.lib.kernelConfig;
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[ (isYes "XEN")
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(isYes "X86_IO_APIC")
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(isYes "ACPI")
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(isYes "XEN_DOM0")
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(isYes "PCI_XEN")
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(isYes "XEN_DEV_EVTCHN")
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(isYes "XENFS")
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(isYes "XEN_COMPAT_XENFS")
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(isYes "XEN_SYS_HYPERVISOR")
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(isYes "XEN_GNTDEV")
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(isYes "XEN_BACKEND")
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(isModule "XEN_NETDEV_BACKEND")
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(isModule "XEN_BLKDEV_BACKEND")
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(isModule "XEN_PCIDEV_BACKEND")
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(isYes "XEN_BALLOON")
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(isYes "XEN_SCRUB_PAGES")
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];
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environment.etc =
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[ { source = "${xen}/etc/xen/xl.conf";
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target = "xen/xl.conf";
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}
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];
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# Xen provides udev rules.
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services.udev.packages = [ xen ];
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services.udev.path = [ pkgs.bridge-utils pkgs.iproute ];
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systemd.services.xen-store = {
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description = "Xen Store Daemon";
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wantedBy = [ "multi-user.target" ];
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after = [ "network.target" "xen-store.socket" ];
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requires = [ "xen-store.socket" ];
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preStart = ''
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export XENSTORED_ROOTDIR="/var/lib/xenstored"
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rm -f "$XENSTORED_ROOTDIR"/tdb* &>/dev/null
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mkdir -p /var/run
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${optionalString cfg.trace "mkdir -p /var/log/xen"}
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grep -q control_d /proc/xen/capabilities
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'';
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serviceConfig.ExecStart = ''
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${cfg.stored}${optionalString cfg.trace " -T /var/log/xen/xenstored-trace.log"} --no-fork
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'';
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postStart = ''
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time=0
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timeout=30
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# Wait for xenstored to actually come up, timing out after 30 seconds
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while [ $time -lt $timeout ] && ! `${pkgs.xen}/bin/xenstore-read -s / >/dev/null 2>&1` ; do
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time=$(($time+1))
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sleep 1
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done
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# Exit if we timed out
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if ! [ $time -lt $timeout ] ; then
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echo "Could not start Xenstore Daemon"
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exit 1
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fi
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${pkgs.xen}/bin/xenstore-write "/local/domain/0/name" "Domain-0"
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${pkgs.xen}/bin/xenstore-write "/local/domain/0/domid" 0
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'';
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};
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systemd.sockets.xen-store = {
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description = "XenStore Socket for userspace API";
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wantedBy = [ "sockets.target" ];
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socketConfig = {
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ListenStream = [ "/var/run/xenstored/socket" "/var/run/xenstored/socket_ro" ];
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SocketMode = "0660";
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SocketUser = "root";
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SocketGroup = "root";
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};
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};
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systemd.services.xen-console = {
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description = "Xen Console Daemon";
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wantedBy = [ "multi-user.target" ];
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after = [ "xen-store.service" ];
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preStart = ''
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mkdir -p /var/run/xen
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${optionalString cfg.trace "mkdir -p /var/log/xen"}
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grep -q control_d /proc/xen/capabilities
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'';
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serviceConfig = {
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ExecStart = ''
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${pkgs.xen}/bin/xenconsoled${optionalString cfg.trace " --log=all --log-dir=/var/log/xen"}
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'';
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};
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};
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systemd.services.xen-qemu = {
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description = "Xen Qemu Daemon";
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wantedBy = [ "multi-user.target" ];
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after = [ "xen-console.service" ];
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serviceConfig.ExecStart = ''
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${pkgs.xen}/lib/xen/bin/qemu-system-i386 -xen-domid 0 -xen-attach -name dom0 -nographic -M xenpv \
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-monitor /dev/null -serial /dev/null -parallel /dev/null
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'';
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};
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systemd.services.xen-watchdog = {
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description = "Xen Watchdog Daemon";
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wantedBy = [ "multi-user.target" ];
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after = [ "xen-qemu.service" ];
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serviceConfig.ExecStart = "${pkgs.xen}/bin/xenwatchdogd 30 15";
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serviceConfig.Type = "forking";
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serviceConfig.RestartSec = "1";
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serviceConfig.Restart = "on-failure";
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};
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systemd.services.xen-bridge = {
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description = "Xen bridge";
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wantedBy = [ "multi-user.target" ];
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before = [ "xen-domains.service" ];
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serviceConfig.RemainAfterExit = "yes";
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serviceConfig.ExecStart = ''
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${pkgs.bridge-utils}/bin/brctl addbr ${cfg.bridge}
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${pkgs.inetutils}/bin/ifconfig ${cfg.bridge} up
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'';
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serviceConfig.ExecStop = ''
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${pkgs.inetutils}/bin/ifconfig ${cfg.bridge} down
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${pkgs.bridge-utils}/bin/brctl delbr ${cfg.bridge}
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'';
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};
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systemd.services.xen-domains = {
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description = "Xen domains - automatically starts, saves and restores Xen domains";
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wantedBy = [ "multi-user.target" ];
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after = [ "xen-bridge.service" "xen-qemu.service" ];
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## To prevent a race between dhcpcd and xend's bridge setup script
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## (which renames eth* to peth* and recreates eth* as a virtual
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## device), start dhcpcd after xend.
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before = [ "dhcpd.service" ];
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restartIfChanged = false;
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serviceConfig.RemainAfterExit = "yes";
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path = [ pkgs.xen ];
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environment.XENDOM_CONFIG = "${pkgs.xen}/etc/sysconfig/xendomains";
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preStart = "mkdir -p /var/lock/subsys -m 755";
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serviceConfig.ExecStart = "${pkgs.xen}/etc/init.d/xendomains start";
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serviceConfig.ExecStop = "${pkgs.xen}/etc/init.d/xendomains stop";
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};
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};
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}
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