Fix #2459: qm: Make info about core limit clear

[pve-docs.git] / qm.adoc

diff --git a/qm.adoc b/qm.adoc
index 4fc83718bdaa47504acde1e234e12802851f2b05..b13f0f4ccb419222bb8dd3729e77801eb515a5a0 100644 (file)
--- a/qm.adoc
+++ b/qm.adoc
@@ -117,16 +117,42 @@ OS Settings
 
 [thumbnail="screenshot/gui-create-vm-os.png"]
 
 
 [thumbnail="screenshot/gui-create-vm-os.png"]
 

-When creating a VM, setting the proper Operating System(OS) allows {pve} to
-optimize some low level parameters. For instance Windows OS expect the BIOS
-clock to use the local time, while Unix based OS expect the BIOS clock to have
-the UTC time.
+When creating a virtual machine (VM), setting the proper Operating System(OS)
+allows {pve} to optimize some low level parameters. For instance Windows OS
+expect the BIOS clock to use the local time, while Unix based OS expect the
+BIOS clock to have the UTC time.

 
 

+[[qm_system_settings]]
+System Settings
+~~~~~~~~~~~~~~~
+
+On VM creation you can change some basic system components of the new VM. You
+can specify which xref:qm_display[display type] you want to use.
+[thumbnail="screenshot/gui-create-vm-system.png"]
+Additionally, the xref:qm_hard_disk[SCSI controller] can be changed.
+If you plan to install the QEMU Guest Agent, or if your selected ISO image
+already ships and installs it automatically, you may want to tick the 'Qemu
+Agent' box, which lets {pve} know that it can use its features to show some
+more information, and complete some actions (for example, shutdown or
+snapshots) more intelligently.
+
+{pve} allows to boot VMs with different firmware and machine types, namely
+xref:qm_bios_and_uefi[SeaBIOS and OVMF]. In most cases you want to switch from
+the default SeabBIOS to OVMF only if you plan to use
+xref:qm_pci_passthrough[PCIe pass through]. A VMs 'Machine Type' defines the
+hardware layout of the VM's virtual motherboard. You can choose between the
+default https://en.wikipedia.org/wiki/Intel_440FX[Intel 440FX] or the
+https://ark.intel.com/content/www/us/en/ark/products/31918/intel-82q35-graphics-and-memory-controller.html[Q35]
+chipset, which also provides a virtual PCIe bus, and thus may be desired if
+one want's to pass through PCIe hardware.

 
 [[qm_hard_disk]]
 Hard Disk
 ~~~~~~~~~
 
 
 [[qm_hard_disk]]
 Hard Disk
 ~~~~~~~~~
 

+[[qm_hard_disk_bus]]
+Bus/Controller
+^^^^^^^^^^^^^^

 Qemu can emulate a number of storage controllers:
 
 * the *IDE* controller, has a design which goes back to the 1984 PC/AT disk
 Qemu can emulate a number of storage controllers:
 
 * the *IDE* controller, has a design which goes back to the 1984 PC/AT disk


@@ -159,6 +185,10 @@ is an older type of paravirtualized controller. It has been superseded by the
 VirtIO SCSI Controller, in terms of features.
 
 [thumbnail="screenshot/gui-create-vm-hard-disk.png"]
 VirtIO SCSI Controller, in terms of features.
 
 [thumbnail="screenshot/gui-create-vm-hard-disk.png"]

+
+[[qm_hard_disk_formats]]
+Image Format
+^^^^^^^^^^^^

 On each controller you attach a number of emulated hard disks, which are backed
 by a file or a block device residing in the configured storage. The choice of
 a storage type will determine the format of the hard disk image. Storages which
 On each controller you attach a number of emulated hard disks, which are backed
 by a file or a block device residing in the configured storage. The choice of
 a storage type will determine the format of the hard disk image. Storages which


@@ -177,6 +207,9 @@ either the *raw disk image format* or the *QEMU image format*.
  * the *VMware image format* only makes sense if you intend to import/export the
  disk image to other hypervisors.
 
  * the *VMware image format* only makes sense if you intend to import/export the
  disk image to other hypervisors.
 

+[[qm_hard_disk_cache]]
+Cache Mode
+^^^^^^^^^^

 Setting the *Cache* mode of the hard drive will impact how the host system will
 notify the guest systems of block write completions. The *No cache* default
 means that the guest system will be notified that a write is complete when each
 Setting the *Cache* mode of the hard drive will impact how the host system will
 notify the guest systems of block write completions. The *No cache* default
 means that the guest system will be notified that a write is complete when each


@@ -192,21 +225,36 @@ As of {pve} 5.0, replication requires the disk images to be on a storage of type
 `zfspool`, so adding a disk image to other storages when the VM has replication
 configured requires to skip replication for this disk image.
 
 `zfspool`, so adding a disk image to other storages when the VM has replication
 configured requires to skip replication for this disk image.
 

+[[qm_hard_disk_discard]]
+Trim/Discard
+^^^^^^^^^^^^

 If your storage supports _thin provisioning_ (see the storage chapter in the
 If your storage supports _thin provisioning_ (see the storage chapter in the

-{pve} guide), and your VM has a *SCSI* controller you can activate the *Discard*
-option on the hard disks connected to that controller. With *Discard* enabled,
-when the filesystem of a VM marks blocks as unused after removing files, the
-emulated SCSI controller will relay this information to the storage, which will
-then shrink the disk image accordingly.
-
-.IO Thread
+{pve} guide), you can activate the *Discard* option on a drive. With *Discard*
+set and a _TRIM_-enabled guest OS footnote:[TRIM, UNMAP, and discard
+https://en.wikipedia.org/wiki/Trim_%28computing%29], when the VM's filesystem
+marks blocks as unused after deleting files, the controller will relay this
+information to the storage, which will then shrink the disk image accordingly.
+For the guest to be able to issue _TRIM_ commands, you must enable the *Discard*
+option on the drive. Some guest operating systems may also require the
+*SSD Emulation* flag to be set. Note that *Discard* on *VirtIO Block* drives is
+only supported on guests using Linux Kernel 5.0 or higher.
+
+If you would like a drive to be presented to the guest as a solid-state drive
+rather than a rotational hard disk, you can set the *SSD emulation* option on
+that drive. There is no requirement that the underlying storage actually be
+backed by SSDs; this feature can be used with physical media of any type.
+Note that *SSD emulation* is not supported on *VirtIO Block* drives.
+
+
+[[qm_hard_disk_iothread]]
+IO Thread
+^^^^^^^^^

 The option *IO Thread* can only be used when using a disk with the
 *VirtIO* controller, or with the *SCSI* controller, when the emulated controller
  type is  *VirtIO SCSI single*.
 With this enabled, Qemu creates one I/O thread per storage controller,
 The option *IO Thread* can only be used when using a disk with the
 *VirtIO* controller, or with the *SCSI* controller, when the emulated controller
  type is  *VirtIO SCSI single*.
 With this enabled, Qemu creates one I/O thread per storage controller,

-instead of a single thread for all I/O, so it increases performance when
-multiple disks are used and each disk has its own storage controller.
-Note that backups do not currently work with *IO Thread* enabled.
+instead of a single thread for all I/O, so it can increase performance when
+multiple isks are used and each disk has its own storage controller.

 
 
 [[qm_cpu]]
 
 
 [[qm_cpu]]


@@ -235,8 +283,8 @@ is greater than the number of cores on the server (e.g., 4 VMs with each 4
 cores on a machine with only 8 cores). In that case the host system will
 balance the Qemu execution threads between your server cores, just like if you
 were running a standard multithreaded application. However, {pve} will prevent
 cores on a machine with only 8 cores). In that case the host system will
 balance the Qemu execution threads between your server cores, just like if you
 were running a standard multithreaded application. However, {pve} will prevent

-you from assigning more virtual CPU cores than physically available, as this will
-only bring the performance down due to the cost of context switches.
+you from starting VMs with more virtual CPU cores than physically available, as
+this will only bring the performance down due to the cost of context switches.

 
 [[qm_cpu_resource_limits]]
 Resource Limits
 
 [[qm_cpu_resource_limits]]
 Resource Limits


@@ -427,7 +475,7 @@ will allow proper distribution of the VM resources on the host system.
 This option is also required to hot-plug cores or RAM in a VM.
 
 If the NUMA option is used, it is recommended to set the number of sockets to
 This option is also required to hot-plug cores or RAM in a VM.
 
 If the NUMA option is used, it is recommended to set the number of sockets to

-the number of sockets of the host system.
+the number of nodes of the host system.

 
 vCPU hot-plug
 ^^^^^^^^^^^^^
 
 vCPU hot-plug
 ^^^^^^^^^^^^^


@@ -590,6 +638,40 @@ traffic increases. We recommend to set this option only when the VM has to
 process a great number of incoming connections, such as when the VM is running
 as a router, reverse proxy or a busy HTTP server doing long polling.
 
 process a great number of incoming connections, such as when the VM is running
 as a router, reverse proxy or a busy HTTP server doing long polling.
 

+[[qm_display]]
+Display
+~~~~~~~
+
+QEMU can virtualize a few types of VGA hardware. Some examples are:
+
+* *std*, the default, emulates a card with Bochs VBE extensions.
+* *cirrus*, this was once the default, it emulates a very old hardware module
+with all its problems. This display type should only be used if really
+necessary footnote:[https://www.kraxel.org/blog/2014/10/qemu-using-cirrus-considered-harmful/
+qemu: using cirrus considered harmful], e.g., if using Windows XP or earlier
+* *vmware*, is a VMWare SVGA-II compatible adapter.
+* *qxl*, is the QXL paravirtualized graphics card. Selecting this also
+enables https://www.spice-space.org/[SPICE] (a remote viewer protocol) for the
+VM.
+
+You can edit the amount of memory given to the virtual GPU, by setting
+the 'memory' option. This can enable higher resolutions inside the VM,
+especially with SPICE/QXL.
+
+As the memory is reserved by display device, selecting Multi-Monitor mode
+for SPICE (e.g., `qxl2` for dual monitors) has some implications:
+
+* Windows needs a device for each monitor, so if your 'ostype' is some
+version of Windows, {pve} gives the VM an extra device per monitor.
+Each device gets the specified amount of memory.
+
+* Linux VMs, can always enable more virtual monitors, but selecting
+a Multi-Monitor mode multiplies the memory given to the device with
+the number of monitors.
+
+Selecting `serialX` as display 'type' disables the VGA output, and redirects
+the Web Console to the selected serial port. A configured display 'memory'
+setting will be ignored in that case.

 
 [[qm_usb_passthrough]]
 USB Passthrough
 
 [[qm_usb_passthrough]]
 USB Passthrough


@@ -633,8 +715,12 @@ BIOS and UEFI
 ~~~~~~~~~~~~~
 
 In order to properly emulate a computer, QEMU needs to use a firmware.
 ~~~~~~~~~~~~~
 
 In order to properly emulate a computer, QEMU needs to use a firmware.

-By default QEMU uses *SeaBIOS* for this, which is an open-source, x86 BIOS
-implementation. SeaBIOS is a good choice for most standard setups.
+Which, on common PCs often known as BIOS or (U)EFI, is executed as one of the
+first steps when booting a VM. It is responsible for doing basic hardware
+initialization and for providing an interface to the firmware and hardware for
+the operating system. By default QEMU uses *SeaBIOS* for this, which is an
+open-source, x86 BIOS implementation. SeaBIOS is a good choice for most
+standard setups.

 
 There are, however, some scenarios in which a BIOS is not a good firmware
 to boot from, e.g. if you want to do VGA passthrough. footnote:[Alex Williamson has a very good blog entry about this.
 
 There are, however, some scenarios in which a BIOS is not a good firmware
 to boot from, e.g. if you want to do VGA passthrough. footnote:[Alex Williamson has a very good blog entry about this.


@@ -660,6 +746,51 @@ you need to set the client resolution in the OVMF menu(which you can reach
 with a press of the ESC button during boot), or you have to choose
 SPICE as the display type.
 
 with a press of the ESC button during boot), or you have to choose
 SPICE as the display type.
 

+[[qm_ivshmem]]
+Inter-VM shared memory
+~~~~~~~~~~~~~~~~~~~~~~
+
+You can add an Inter-VM shared memory device (`ivshmem`), which allows one to
+share memory between the host and a guest, or also between multiple guests.
+
+To add such a device, you can use `qm`:
+
+  qm set <vmid> -ivshmem size=32,name=foo
+
+Where the size is in MiB. The file will be located under
+`/dev/shm/pve-shm-$name` (the default name is the vmid).
+
+NOTE: Currently the device will get deleted as soon as any VM using it got
+shutdown or stopped. Open connections will still persist, but new connections
+to the exact same device cannot be made anymore.
+
+A use case for such a device is the Looking Glass
+footnote:[Looking Glass: https://looking-glass.hostfission.com/] project,
+which enables high performance, low-latency display mirroring between
+host and guest.
+
+[[qm_audio_device]]
+Audio Device
+~~~~~~~~~~~~
+
+To add an audio device run the following command:
+
+----
+qm set <vmid> -audio0 device=<device>
+----
+
+Supported audio devices are:
+
+* `ich9-intel-hda`: Intel HD Audio Controller, emulates ICH9
+* `intel-hda`: Intel HD Audio Controller, emulates ICH6
+* `AC97`: Audio Codec '97, useful for older operating systems like Windows XP
+
+NOTE: The audio device works only in combination with SPICE. Remote protocols
+like Microsoft's RDP have options to play sound. To use the physical audio
+device of the host use device passthrough (see
+xref:qm_pci_passthrough[PCI Passthrough] and
+xref:qm_usb_passthrough[USB Passthrough]).
+

 [[qm_startup_and_shutdown]]
 Automatic Start and Shutdown of Virtual Machines
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 [[qm_startup_and_shutdown]]
 Automatic Start and Shutdown of Virtual Machines
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


@@ -704,6 +835,70 @@ start after those where the parameter is set. Further, this parameter can only
 be enforced between virtual machines running on the same host, not
 cluster-wide.
 
 be enforced between virtual machines running on the same host, not
 cluster-wide.
 

+[[qm_spice_enhancements]]
+SPICE Enhancements
+~~~~~~~~~~~~~~~~~~
+
+SPICE Enhancements are optional features that can improve the remote viewer
+experience.
+
+To enable them via the GUI go to the *Options* panel of the virtual machine. Run
+the following command to enable them via the CLI:
+
+----
+qm set <vmid> -spice_enhancements foldersharing=1,videostreaming=all
+----
+
+NOTE: To use these features the <<qm_display,*Display*>> of the virtual machine
+must be set to SPICE (qxl).
+
+Folder Sharing
+^^^^^^^^^^^^^^
+
+Share a local folder with the guest. The `spice-webdavd` daemon needs to be
+installed in the guest. It makes the shared folder available through a local
+WebDAV server located at http://localhost:9843.
+
+For Windows guests the installer for the 'Spice WebDAV daemon' can be downloaded
+from the
+https://www.spice-space.org/download.html#windows-binaries[official SPICE website].
+
+Most Linux distributions have a package called `spice-webdavd` that can be
+installed.
+
+To share a folder in Virt-Viewer (Remote Viewer) go to 'File -> Preferences'.
+Select the folder to share and then enable the checkbox.
+
+NOTE: Folder sharing currently only works in the Linux version of Virt-Viewer.
+
+CAUTION: Experimental! Currently this feature does not work reliably.
+
+Video Streaming
+^^^^^^^^^^^^^^^
+
+Fast refreshing areas are encoded into a video stream. Two options exist:
+
+* *all*: Any fast refreshing area will be encoded into a video stream.
+* *filter*: Additional filters are used to decide if video streaming should be
+  used (currently only small window surfaces are skipped).
+
+A general recommendation if video streaming should be enabled and which option
+to choose from cannot be given. Your mileage may vary depending on the specific
+circumstances.
+
+Troubleshooting
+^^^^^^^^^^^^^^^
+
+.Shared folder does not show up
+
+Make sure the WebDAV service is enabled and running in the guest. On Windows it
+is called 'Spice webdav proxy'. In Linux the name is 'spice-webdavd' but can be
+different depending on the distribution.
+
+If the service is running, check the WebDAV server by opening
+http://localhost:9843 in a browser in the guest.
+
+It can help to restart the SPICE session.

 
 [[qm_migration]]
 Migration
 
 [[qm_migration]]
 Migration


@@ -786,7 +981,7 @@ migrate a VM to a totally different storage. You can also change the
 disk image *Format* if the storage driver supports several formats.
 +
 
 disk image *Format* if the storage driver supports several formats.
 +
 

-NOTE: A full clone need to read and copy all VM image data. This is
+NOTE: A full clone needs to read and copy all VM image data. This is

 usually much slower than creating a linked clone.
 +
 
 usually much slower than creating a linked clone.
 +
 


@@ -797,7 +992,7 @@ never includes any additional snapshots from the original VM.
 
 Linked Clone::
 
 
 Linked Clone::
 

-Modern storage drivers supports a way to generate fast linked
+Modern storage drivers support a way to generate fast linked

 clones. Such a clone is a writable copy whose initial contents are the
 same as the original data. Creating a linked clone is nearly
 instantaneous, and initially consumes no additional space.
 clones. Such a clone is a writable copy whose initial contents are the
 same as the original data. Creating a linked clone is nearly
 instantaneous, and initially consumes no additional space.


@@ -814,8 +1009,8 @@ can convert any VM into a read-only <<qm_templates, Template>>). Such
 templates can later be used to create linked clones efficiently.
 +
 
 templates can later be used to create linked clones efficiently.
 +
 

-NOTE: You cannot delete the original template while linked clones
-exists.
+NOTE: You cannot delete an original template while linked clones
+exist.

 +
 
 It is not possible to change the *Target storage* for linked clones,
 +
 
 It is not possible to change the *Target storage* for linked clones,


@@ -826,7 +1021,7 @@ The *Target node* option allows you to create the new VM on a
 different node. The only restriction is that the VM is on shared
 storage, and that storage is also available on the target node.
 
 different node. The only restriction is that the VM is on shared
 storage, and that storage is also available on the target node.
 

-To avoid resource conflicts, all network interface MAC addresses gets
+To avoid resource conflicts, all network interface MAC addresses get

 randomized, and we generate a new 'UUID' for the VM BIOS (smbios1)
 setting.
 
 randomized, and we generate a new 'UUID' for the VM BIOS (smbios1)
 setting.
 


@@ -845,7 +1040,7 @@ clone and modify that.
 VM Generation ID
 ----------------
 
 VM Generation ID
 ----------------
 

-{pve} supports Virtual Machine Generation ID ('vmgedid') footnote:[Official
+{pve} supports Virtual Machine Generation ID ('vmgenid') footnote:[Official

 'vmgenid' Specification
 https://docs.microsoft.com/en-us/windows/desktop/hyperv_v2/virtual-machine-generation-identifier]
 for virtual machines.
 'vmgenid' Specification
 https://docs.microsoft.com/en-us/windows/desktop/hyperv_v2/virtual-machine-generation-identifier]
 for virtual machines.


@@ -983,7 +1178,20 @@ ifndef::wiki[]
 include::qm-cloud-init.adoc[]
 endif::wiki[]
 
 include::qm-cloud-init.adoc[]
 endif::wiki[]
 

+ifndef::wiki[]
+include::qm-pci-passthrough.adoc[]
+endif::wiki[]
+
+Hookscripts
+-----------
+
+You can add a hook script to VMs with the config property `hookscript`.
+
+ qm set 100 -hookscript local:snippets/hookscript.pl

 
 

+It will be called during various phases of the guests lifetime.
+For an example and documentation see the example script under
+`/usr/share/pve-docs/examples/guest-example-hookscript.pl`.

 
 Managing Virtual Machines with `qm`
 ------------------------------------
 
 Managing Virtual Machines with `qm`
 ------------------------------------