1 [[chapter_virtual_machines]]
10 qm - Qemu/KVM Virtual Machine Manager
16 include::qm.1-synopsis.adoc[]
22 Qemu/KVM Virtual Machines
23 =========================
28 // http://pve.proxmox.com/wiki/Container_and_Full_Virtualization
29 // http://pve.proxmox.com/wiki/KVM
30 // http://pve.proxmox.com/wiki/Qemu_Server
32 Qemu (short form for Quick Emulator) is an open source hypervisor that emulates a
33 physical computer. From the perspective of the host system where Qemu is
34 running, Qemu is a user program which has access to a number of local resources
35 like partitions, files, network cards which are then passed to an
36 emulated computer which sees them as if they were real devices.
38 A guest operating system running in the emulated computer accesses these
39 devices, and runs as it were running on real hardware. For instance you can pass
40 an iso image as a parameter to Qemu, and the OS running in the emulated computer
41 will see a real CDROM inserted in a CD drive.
43 Qemu can emulate a great variety of hardware from ARM to Sparc, but {pve} is
44 only concerned with 32 and 64 bits PC clone emulation, since it represents the
45 overwhelming majority of server hardware. The emulation of PC clones is also one
46 of the fastest due to the availability of processor extensions which greatly
47 speed up Qemu when the emulated architecture is the same as the host
50 NOTE: You may sometimes encounter the term _KVM_ (Kernel-based Virtual Machine).
51 It means that Qemu is running with the support of the virtualization processor
52 extensions, via the Linux kvm module. In the context of {pve} _Qemu_ and
53 _KVM_ can be used interchangeably as Qemu in {pve} will always try to load the kvm
56 Qemu inside {pve} runs as a root process, since this is required to access block
60 Emulated devices and paravirtualized devices
61 --------------------------------------------
63 The PC hardware emulated by Qemu includes a mainboard, network controllers,
64 scsi, ide and sata controllers, serial ports (the complete list can be seen in
65 the `kvm(1)` man page) all of them emulated in software. All these devices
66 are the exact software equivalent of existing hardware devices, and if the OS
67 running in the guest has the proper drivers it will use the devices as if it
68 were running on real hardware. This allows Qemu to runs _unmodified_ operating
71 This however has a performance cost, as running in software what was meant to
72 run in hardware involves a lot of extra work for the host CPU. To mitigate this,
73 Qemu can present to the guest operating system _paravirtualized devices_, where
74 the guest OS recognizes it is running inside Qemu and cooperates with the
77 Qemu relies on the virtio virtualization standard, and is thus able to presente
78 paravirtualized virtio devices, which includes a paravirtualized generic disk
79 controller, a paravirtualized network card, a paravirtualized serial port,
80 a paravirtualized SCSI controller, etc ...
82 It is highly recommended to use the virtio devices whenever you can, as they
83 provide a big performance improvement. Using the virtio generic disk controller
84 versus an emulated IDE controller will double the sequential write throughput,
85 as measured with `bonnie++(8)`. Using the virtio network interface can deliver
86 up to three times the throughput of an emulated Intel E1000 network card, as
87 measured with `iperf(1)`. footnote:[See this benchmark on the KVM wiki
88 http://www.linux-kvm.org/page/Using_VirtIO_NIC]
91 [[qm_virtual_machines_settings]]
92 Virtual Machines Settings
93 -------------------------
95 Generally speaking {pve} tries to choose sane defaults for virtual machines
96 (VM). Make sure you understand the meaning of the settings you change, as it
97 could incur a performance slowdown, or putting your data at risk.
100 [[qm_general_settings]]
104 [thumbnail="gui-create-vm-general.png"]
106 General settings of a VM include
108 * the *Node* : the physical server on which the VM will run
109 * the *VM ID*: a unique number in this {pve} installation used to identify your VM
110 * *Name*: a free form text string you can use to describe the VM
111 * *Resource Pool*: a logical group of VMs
118 [thumbnail="gui-create-vm-os.png"]
120 When creating a VM, setting the proper Operating System(OS) allows {pve} to
121 optimize some low level parameters. For instance Windows OS expect the BIOS
122 clock to use the local time, while Unix based OS expect the BIOS clock to have
130 Qemu can emulate a number of storage controllers:
132 * the *IDE* controller, has a design which goes back to the 1984 PC/AT disk
133 controller. Even if this controller has been superseded by more more designs,
134 each and every OS you can think of has support for it, making it a great choice
135 if you want to run an OS released before 2003. You can connect up to 4 devices
138 * the *SATA* (Serial ATA) controller, dating from 2003, has a more modern
139 design, allowing higher throughput and a greater number of devices to be
140 connected. You can connect up to 6 devices on this controller.
142 * the *SCSI* controller, designed in 1985, is commonly found on server grade
143 hardware, and can connect up to 14 storage devices. {pve} emulates by default a
144 LSI 53C895A controller.
146 A SCSI controller of type _VirtIO SCSI_ is the recommended setting if you aim for
147 performance and is automatically selected for newly created Linux VMs since
148 {pve} 4.3. Linux distributions have support for this controller since 2012, and
149 FreeBSD since 2014. For Windows OSes, you need to provide an extra iso
150 containing the drivers during the installation.
151 // https://pve.proxmox.com/wiki/Paravirtualized_Block_Drivers_for_Windows#During_windows_installation.
152 If you aim at maximum performance, you can select a SCSI controller of type
153 _VirtIO SCSI single_ which will allow you to select the *IO Thread* option.
154 When selecting _VirtIO SCSI single_ Qemu will create a new controller for
155 each disk, instead of adding all disks to the same controller.
157 * The *Virtio* controller, also called virtio-blk to distinguish from
158 the VirtIO SCSI controller, is an older type of paravirtualized controller
159 which has been superseded in features by the Virtio SCSI Controller.
161 [thumbnail="gui-create-vm-hard-disk.png"]
162 On each controller you attach a number of emulated hard disks, which are backed
163 by a file or a block device residing in the configured storage. The choice of
164 a storage type will determine the format of the hard disk image. Storages which
165 present block devices (LVM, ZFS, Ceph) will require the *raw disk image format*,
166 whereas files based storages (Ext4, NFS, GlusterFS) will let you to choose
167 either the *raw disk image format* or the *QEMU image format*.
169 * the *QEMU image format* is a copy on write format which allows snapshots, and
170 thin provisioning of the disk image.
171 * the *raw disk image* is a bit-to-bit image of a hard disk, similar to what
172 you would get when executing the `dd` command on a block device in Linux. This
173 format do not support thin provisioning or snapshotting by itself, requiring
174 cooperation from the storage layer for these tasks. It is however 10% faster
175 than the *QEMU image format*. footnote:[See this benchmark for details
176 http://events.linuxfoundation.org/sites/events/files/slides/CloudOpen2013_Khoa_Huynh_v3.pdf]
177 * the *VMware image format* only makes sense if you intend to import/export the
178 disk image to other hypervisors.
180 Setting the *Cache* mode of the hard drive will impact how the host system will
181 notify the guest systems of block write completions. The *No cache* default
182 means that the guest system will be notified that a write is complete when each
183 block reaches the physical storage write queue, ignoring the host page cache.
184 This provides a good balance between safety and speed.
186 If you want the {pve} backup manager to skip a disk when doing a backup of a VM,
187 you can set the *No backup* option on that disk.
189 If you want the {pve} storage replication mechanism to skip a disk when starting
190 a replication job, you can set the *Skip replication* option on that disk.
191 As of {pve} 5.0, replication requires the disk images to be on a storage of type
192 `zfspool`, so adding a disk image to other storages when the VM has replication
193 configured requires to skip replication for this disk image.
195 If your storage supports _thin provisioning_ (see the storage chapter in the
196 {pve} guide), and your VM has a *SCSI* controller you can activate the *Discard*
197 option on the hard disks connected to that controller. With *Discard* enabled,
198 when the filesystem of a VM marks blocks as unused after removing files, the
199 emulated SCSI controller will relay this information to the storage, which will
200 then shrink the disk image accordingly.
203 The option *IO Thread* can only be used when using a disk with the
204 *VirtIO* controller, or with the *SCSI* controller, when the emulated controller
205 type is *VirtIO SCSI single*.
206 With this enabled, Qemu creates one I/O thread per storage controller,
207 instead of a single thread for all I/O, so it increases performance when
208 multiple disks are used and each disk has its own storage controller.
209 Note that backups do not currently work with *IO Thread* enabled.
216 [thumbnail="gui-create-vm-cpu.png"]
218 A *CPU socket* is a physical slot on a PC motherboard where you can plug a CPU.
219 This CPU can then contain one or many *cores*, which are independent
220 processing units. Whether you have a single CPU socket with 4 cores, or two CPU
221 sockets with two cores is mostly irrelevant from a performance point of view.
222 However some software is licensed depending on the number of sockets you have in
223 your machine, in that case it makes sense to set the number of of sockets to
224 what the license allows you, and increase the number of cores.
226 Increasing the number of virtual cpus (cores and sockets) will usually provide a
227 performance improvement though that is heavily dependent on the use of the VM.
228 Multithreaded applications will of course benefit from a large number of
229 virtual cpus, as for each virtual cpu you add, Qemu will create a new thread of
230 execution on the host system. If you're not sure about the workload of your VM,
231 it is usually a safe bet to set the number of *Total cores* to 2.
233 NOTE: It is perfectly safe to set the _overall_ number of total cores in all
234 your VMs to be greater than the number of of cores you have on your server (ie.
235 4 VMs with each 4 Total cores running in a 8 core machine is OK) In that case
236 the host system will balance the Qemu execution threads between your server
237 cores just like if you were running a standard multithreaded application.
238 However {pve} will prevent you to allocate on a _single_ machine more vcpus than
239 physically available, as this will only bring the performance down due to the
240 cost of context switches.
242 Qemu can emulate a number different of *CPU types* from 486 to the latest Xeon
243 processors. Each new processor generation adds new features, like hardware
244 assisted 3d rendering, random number generation, memory protection, etc ...
245 Usually you should select for your VM a processor type which closely matches the
246 CPU of the host system, as it means that the host CPU features (also called _CPU
247 flags_ ) will be available in your VMs. If you want an exact match, you can set
248 the CPU type to *host* in which case the VM will have exactly the same CPU flags
251 This has a downside though. If you want to do a live migration of VMs between
252 different hosts, your VM might end up on a new system with a different CPU type.
253 If the CPU flags passed to the guest are missing, the qemu process will stop. To
254 remedy this Qemu has also its own CPU type *kvm64*, that {pve} uses by defaults.
255 kvm64 is a Pentium 4 look a like CPU type, which has a reduced CPU flags set,
256 but is guaranteed to work everywhere.
258 In short, if you care about live migration and moving VMs between nodes, leave
259 the kvm64 default. If you don’t care about live migration, set the CPU type to
260 host, as in theory this will give your guests maximum performance.
262 You can also optionally emulate a *NUMA* architecture in your VMs. The basics of
263 the NUMA architecture mean that instead of having a global memory pool available
264 to all your cores, the memory is spread into local banks close to each socket.
265 This can bring speed improvements as the memory bus is not a bottleneck
266 anymore. If your system has a NUMA architecture footnote:[if the command
267 `numactl --hardware | grep available` returns more than one node, then your host
268 system has a NUMA architecture] we recommend to activate the option, as this
269 will allow proper distribution of the VM resources on the host system. This
270 option is also required in {pve} to allow hotplugging of cores and RAM to a VM.
272 If the NUMA option is used, it is recommended to set the number of sockets to
273 the number of sockets of the host system.
280 For each VM you have the option to set a fixed size memory or asking
281 {pve} to dynamically allocate memory based on the current RAM usage of the
284 .Fixed Memory Allocation
285 [thumbnail="gui-create-vm-memory-fixed.png"]
287 When choosing a *fixed size memory* {pve} will simply allocate what you
290 Even when using a fixed memory size, the ballooning device gets added to the
291 VM, because it delivers useful information such as how much memory the guest
293 In general, you should leave *ballooning* enabled, but if you want to disable
294 it (e.g. for debugging purposes), simply uncheck
299 in the configuration.
301 .Automatic Memory Allocation
302 [thumbnail="gui-create-vm-memory-dynamic.png", float="left"]
304 // see autoballoon() in pvestatd.pm
305 When choosing to *automatically allocate memory*, {pve} will make sure that the
306 minimum amount you specified is always available to the VM, and if RAM usage on
307 the host is below 80%, will dynamically add memory to the guest up to the
308 maximum memory specified.
310 When the host is becoming short on RAM, the VM will then release some memory
311 back to the host, swapping running processes if needed and starting the oom
312 killer in last resort. The passing around of memory between host and guest is
313 done via a special `balloon` kernel driver running inside the guest, which will
314 grab or release memory pages from the host.
315 footnote:[A good explanation of the inner workings of the balloon driver can be found here https://rwmj.wordpress.com/2010/07/17/virtio-balloon/]
317 When multiple VMs use the autoallocate facility, it is possible to set a
318 *Shares* coefficient which indicates the relative amount of the free host memory
319 that each VM shoud take. Suppose for instance you have four VMs, three of them
320 running a HTTP server and the last one is a database server. To cache more
321 database blocks in the database server RAM, you would like to prioritize the
322 database VM when spare RAM is available. For this you assign a Shares property
323 of 3000 to the database VM, leaving the other VMs to the Shares default setting
324 of 1000. The host server has 32GB of RAM, and is curring using 16GB, leaving 32
325 * 80/100 - 16 = 9GB RAM to be allocated to the VMs. The database VM will get 9 *
326 3000 / (3000 + 1000 + 1000 + 1000) = 4.5 GB extra RAM and each HTTP server will
329 All Linux distributions released after 2010 have the balloon kernel driver
330 included. For Windows OSes, the balloon driver needs to be added manually and can
331 incur a slowdown of the guest, so we don't recommend using it on critical
333 // see https://forum.proxmox.com/threads/solved-hyper-threading-vs-no-hyper-threading-fixed-vs-variable-memory.20265/
335 When allocating RAMs to your VMs, a good rule of thumb is always to leave 1GB
336 of RAM available to the host.
339 [[qm_network_device]]
343 [thumbnail="gui-create-vm-network.png"]
345 Each VM can have many _Network interface controllers_ (NIC), of four different
348 * *Intel E1000* is the default, and emulates an Intel Gigabit network card.
349 * the *VirtIO* paravirtualized NIC should be used if you aim for maximum
350 performance. Like all VirtIO devices, the guest OS should have the proper driver
352 * the *Realtek 8139* emulates an older 100 MB/s network card, and should
353 only be used when emulating older operating systems ( released before 2002 )
354 * the *vmxnet3* is another paravirtualized device, which should only be used
355 when importing a VM from another hypervisor.
357 {pve} will generate for each NIC a random *MAC address*, so that your VM is
358 addressable on Ethernet networks.
360 The NIC you added to the VM can follow one of two differents models:
362 * in the default *Bridged mode* each virtual NIC is backed on the host by a
363 _tap device_, ( a software loopback device simulating an Ethernet NIC ). This
364 tap device is added to a bridge, by default vmbr0 in {pve}. In this mode, VMs
365 have direct access to the Ethernet LAN on which the host is located.
366 * in the alternative *NAT mode*, each virtual NIC will only communicate with
367 the Qemu user networking stack, where a builting router and DHCP server can
368 provide network access. This built-in DHCP will serve adresses in the private
369 10.0.2.0/24 range. The NAT mode is much slower than the bridged mode, and
370 should only be used for testing.
372 You can also skip adding a network device when creating a VM by selecting *No
376 If you are using the VirtIO driver, you can optionally activate the
377 *Multiqueue* option. This option allows the guest OS to process networking
378 packets using multiple virtual CPUs, providing an increase in the total number
379 of packets transfered.
381 //http://blog.vmsplice.net/2011/09/qemu-internals-vhost-architecture.html
382 When using the VirtIO driver with {pve}, each NIC network queue is passed to the
383 host kernel, where the queue will be processed by a kernel thread spawn by the
384 vhost driver. With this option activated, it is possible to pass _multiple_
385 network queues to the host kernel for each NIC.
387 //https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Virtualization_Tuning_and_Optimization_Guide/sect-Virtualization_Tuning_Optimization_Guide-Networking-Techniques.html#sect-Virtualization_Tuning_Optimization_Guide-Networking-Multi-queue_virtio-net
388 When using Multiqueue, it is recommended to set it to a value equal
389 to the number of Total Cores of your guest. You also need to set in
390 the VM the number of multi-purpose channels on each VirtIO NIC with the ethtool
393 `ethtool -L ens1 combined X`
395 where X is the number of the number of vcpus of the VM.
397 You should note that setting the Multiqueue parameter to a value greater
398 than one will increase the CPU load on the host and guest systems as the
399 traffic increases. We recommend to set this option only when the VM has to
400 process a great number of incoming connections, such as when the VM is running
401 as a router, reverse proxy or a busy HTTP server doing long polling.
404 [[qm_usb_passthrough]]
408 There are two different types of USB passthrough devices:
410 * Host USB passtrough
411 * SPICE USB passthrough
413 Host USB passthrough works by giving a VM a USB device of the host.
414 This can either be done via the vendor- and product-id, or
415 via the host bus and port.
417 The vendor/product-id looks like this: *0123:abcd*,
418 where *0123* is the id of the vendor, and *abcd* is the id
419 of the product, meaning two pieces of the same usb device
422 The bus/port looks like this: *1-2.3.4*, where *1* is the bus
423 and *2.3.4* is the port path. This represents the physical
424 ports of your host (depending of the internal order of the
427 If a device is present in a VM configuration when the VM starts up,
428 but the device is not present in the host, the VM can boot without problems.
429 As soon as the device/port ist available in the host, it gets passed through.
431 WARNING: Using this kind of USB passthrough means that you cannot move
432 a VM online to another host, since the hardware is only available
433 on the host the VM is currently residing.
435 The second type of passthrough is SPICE USB passthrough. This is useful
436 if you use a SPICE client which supports it. If you add a SPICE USB port
437 to your VM, you can passthrough a USB device from where your SPICE client is,
438 directly to the VM (for example an input device or hardware dongle).
445 In order to properly emulate a computer, QEMU needs to use a firmware.
446 By default QEMU uses *SeaBIOS* for this, which is an open-source, x86 BIOS
447 implementation. SeaBIOS is a good choice for most standard setups.
449 There are, however, some scenarios in which a BIOS is not a good firmware
450 to boot from, e.g. if you want to do VGA passthrough. footnote:[Alex Williamson has a very good blog entry about this.
451 http://vfio.blogspot.co.at/2014/08/primary-graphics-assignment-without-vga.html]
452 In such cases, you should rather use *OVMF*, which is an open-source UEFI implemenation. footnote:[See the OVMF Project http://www.tianocore.org/ovmf/]
454 If you want to use OVMF, there are several things to consider:
456 In order to save things like the *boot order*, there needs to be an EFI Disk.
457 This disk will be included in backups and snapshots, and there can only be one.
459 You can create such a disk with the following command:
461 qm set <vmid> -efidisk0 <storage>:1,format=<format>
463 Where *<storage>* is the storage where you want to have the disk, and
464 *<format>* is a format which the storage supports. Alternatively, you can
465 create such a disk through the web interface with 'Add' -> 'EFI Disk' in the
466 hardware section of a VM.
468 When using OVMF with a virtual display (without VGA passthrough),
469 you need to set the client resolution in the OVMF menu(which you can reach
470 with a press of the ESC button during boot), or you have to choose
471 SPICE as the display type.
473 [[qm_startup_and_shutdown]]
474 Automatic Start and Shutdown of Virtual Machines
475 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
477 After creating your VMs, you probably want them to start automatically
478 when the host system boots. For this you need to select the option 'Start at
479 boot' from the 'Options' Tab of your VM in the web interface, or set it with
480 the following command:
482 qm set <vmid> -onboot 1
484 .Start and Shutdown Order
486 [thumbnail="gui-qemu-edit-start-order.png"]
488 In some case you want to be able to fine tune the boot order of your
489 VMs, for instance if one of your VM is providing firewalling or DHCP
490 to other guest systems. For this you can use the following
493 * *Start/Shutdown order*: Defines the start order priority. E.g. set it to 1 if
494 you want the VM to be the first to be started. (We use the reverse startup
495 order for shutdown, so a machine with a start order of 1 would be the last to
497 * *Startup delay*: Defines the interval between this VM start and subsequent
498 VMs starts . E.g. set it to 240 if you want to wait 240 seconds before starting
500 * *Shutdown timeout*: Defines the duration in seconds {pve} should wait
501 for the VM to be offline after issuing a shutdown command.
502 By default this value is set to 60, which means that {pve} will issue a
503 shutdown request, wait 60s for the machine to be offline, and if after 60s
504 the machine is still online will notify that the shutdown action failed.
506 NOTE: VMs managed by the HA stack do not follow the 'start on boot' and
507 'boot order' options currently. Those VMs will be skipped by the startup and
508 shutdown algorithm as the HA manager itself ensures that VMs get started and
511 Please note that machines without a Start/Shutdown order parameter will always
512 start after those where the parameter is set, and this parameter only
513 makes sense between the machines running locally on a host, and not
521 [thumbnail="gui-qemu-migrate.png"]
523 If you have a cluster, you can migrate your VM to another host with
525 qm migrate <vmid> <target>
527 There are generally two mechanisms for this
529 * Online Migration (aka Live Migration)
535 When your VM is running and it has no local resources defined (such as disks
536 on local storage, passed through devices, etc.) you can initiate a live
537 migration with the -online flag.
542 This starts a Qemu Process on the target host with the 'incoming' flag, which
543 means that the process starts and waits for the memory data and device states
544 from the source Virtual Machine (since all other resources, e.g. disks,
545 are shared, the memory content and device state are the only things left
548 Once this connection is established, the source begins to send the memory
549 content asynchronously to the target. If the memory on the source changes,
550 those sections are marked dirty and there will be another pass of sending data.
551 This happens until the amount of data to send is so small that it can
552 pause the VM on the source, send the remaining data to the target and start
553 the VM on the target in under a second.
558 For Live Migration to work, there are some things required:
560 * The VM has no local resources (e.g. passed through devices, local disks, etc.)
561 * The hosts are in the same {pve} cluster.
562 * The hosts have a working (and reliable) network connection.
563 * The target host must have the same or higher versions of the
564 {pve} packages. (It *might* work the other way, but this is never guaranteed)
569 If you have local resources, you can still offline migrate your VMs,
570 as long as all disk are on storages, which are defined on both hosts.
571 Then the migration will copy the disk over the network to the target host.
573 [[qm_copy_and_clone]]
577 [thumbnail="gui-qemu-full-clone.png"]
579 VM installation is usually done using an installation media (CD-ROM)
580 from the operation system vendor. Depending on the OS, this can be a
581 time consuming task one might want to avoid.
583 An easy way to deploy many VMs of the same type is to copy an existing
584 VM. We use the term 'clone' for such copies, and distinguish between
585 'linked' and 'full' clones.
589 The result of such copy is an independent VM. The
590 new VM does not share any storage resources with the original.
593 It is possible to select a *Target Storage*, so one can use this to
594 migrate a VM to a totally different storage. You can also change the
595 disk image *Format* if the storage driver supports several formats.
598 NOTE: A full clone need to read and copy all VM image data. This is
599 usually much slower than creating a linked clone.
602 Some storage types allows to copy a specific *Snapshot*, which
603 defaults to the 'current' VM data. This also means that the final copy
604 never includes any additional snapshots from the original VM.
609 Modern storage drivers supports a way to generate fast linked
610 clones. Such a clone is a writable copy whose initial contents are the
611 same as the original data. Creating a linked clone is nearly
612 instantaneous, and initially consumes no additional space.
615 They are called 'linked' because the new image still refers to the
616 original. Unmodified data blocks are read from the original image, but
617 modification are written (and afterwards read) from a new
618 location. This technique is called 'Copy-on-write'.
621 This requires that the original volume is read-only. With {pve} one
622 can convert any VM into a read-only <<qm_templates, Template>>). Such
623 templates can later be used to create linked clones efficiently.
626 NOTE: You cannot delete the original template while linked clones
630 It is not possible to change the *Target storage* for linked clones,
631 because this is a storage internal feature.
634 The *Target node* option allows you to create the new VM on a
635 different node. The only restriction is that the VM is on shared
636 storage, and that storage is also available on the target node.
638 To avoid resource conflicts, all network interface MAC addresses gets
639 randomized, and we generate a new 'UUID' for the VM BIOS (smbios1)
644 Virtual Machine Templates
645 -------------------------
647 One can convert a VM into a Template. Such templates are read-only,
648 and you can use them to create linked clones.
650 NOTE: It is not possible to start templates, because this would modify
651 the disk images. If you want to change the template, create a linked
652 clone and modify that.
654 Importing Virtual Machines from foreign hypervisors
655 ---------------------------------------------------
657 A VM export from a foreign hypervisor takes usually the form of one or more disk
658 images, with a configuration file describing the settings of the VM (RAM,
660 The disk images can be in the vmdk format, if the disks come from
661 VMware or VirtualBox, or qcow2 if the disks come from a KVM hypervisor.
662 The most popular configuration format for VM exports is the OVF standard, but in
663 practice interoperation is limited because many settings are not implemented in
664 the standard itself, and hypervisors export the supplementary information
665 in non-standard extensions.
667 Besides the problem of format, importing disk images from other hypervisors
668 may fail if the emulated hardware changes too much from one hypervisor to
669 another. Windows VMs are particularly concerned by this, as the OS is very
670 picky about any changes of hardware. This problem may be solved by
671 installing the MergeIDE.zip utility available from the Internet before exporting
672 and choosing a hard disk type of *IDE* before booting the imported Windows VM.
674 Finally there is the question of paravirtualized drivers, which improve the
675 speed of the emulated system and are specific to the hypervisor.
676 GNU/Linux and other free Unix OSes have all the necessary drivers installed by
677 default and you can switch to the paravirtualized drivers right after importing
678 the VM. For Windows VMs, you need to install the Windows paravirtualized
681 GNU/Linux and other free Unix can usually be imported without hassle. Note
682 that we cannot guarantee a successful import/export of Windows WM in all
683 cases due to the problems above.
685 Step-by-step example of a Windows disk image import
686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
689 https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/[Virtual Machines exports]
690 in different formats for browser testing. We are going to use one of these to
691 demonstrate a VMDK import.
693 Download the export zip
694 ^^^^^^^^^^^^^^^^^^^^^^^
696 After getting informed about the user agreement, choose the _Microsoft Edge on
697 Windows 10 Virtual Machine_ for the VMware platform, and download the zip.
699 Extract the disk image from the zip
700 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
702 Using the unzip utility or any archiver of your choice, unpack the zip,
703 and copy via ssh/scp the vmdk file to your {pve} host.
705 Create a new virtual machine and import the disk
706 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
708 Create a virtual machine with 2 cores, 2GB RAM, and one NIC on the default
711 qm create 999 -net0 e1000,bridge=vmbr0 -name Win10 -memory 2048 -bootdisk sata0
713 Import the disk image to the +local-lvm+ storage:
715 qm importdisk 999 MSEdge "MSEdge - Win10_preview.vmdk" local-lvm
717 The disk will be marked as *Unused* in the VM 999 configuration.
718 After that you can go in the GUI, in the VM *Hardware*, *Edit* the unused disk
719 and set the *Bus/Device* to *SATA/0*.
720 The VM is ready to be started.
723 Managing Virtual Machines with `qm`
724 ------------------------------------
726 qm is the tool to manage Qemu/Kvm virtual machines on {pve}. You can
727 create and destroy virtual machines, and control execution
728 (start/stop/suspend/resume). Besides that, you can use qm to set
729 parameters in the associated config file. It is also possible to
730 create and delete virtual disks.
735 Using an iso file uploaded on the 'local' storage, create a VM
736 with a 4 GB IDE disk on the 'local-lvm' storage
738 qm create 300 -ide0 local-lvm:4 -net0 e1000 -cdrom local:iso/proxmox-mailgateway_2.1.iso
744 Send a shutdown request, then wait until the VM is stopped.
746 qm shutdown 300 && qm wait 300
748 Same as above, but only wait for 40 seconds.
750 qm shutdown 300 && qm wait 300 -timeout 40
757 VM configuration files are stored inside the Proxmox cluster file
758 system, and can be accessed at `/etc/pve/qemu-server/<VMID>.conf`.
759 Like other files stored inside `/etc/pve/`, they get automatically
760 replicated to all other cluster nodes.
762 NOTE: VMIDs < 100 are reserved for internal purposes, and VMIDs need to be
765 .Example VM Configuration
773 net0: e1000=EE:D2:28:5F:B6:3E,bridge=vmbr0
774 virtio0: local:vm-100-disk-1,size=32G
777 Those configuration files are simple text files, and you can edit them
778 using a normal text editor (`vi`, `nano`, ...). This is sometimes
779 useful to do small corrections, but keep in mind that you need to
780 restart the VM to apply such changes.
782 For that reason, it is usually better to use the `qm` command to
783 generate and modify those files, or do the whole thing using the GUI.
784 Our toolkit is smart enough to instantaneously apply most changes to
785 running VM. This feature is called "hot plug", and there is no
786 need to restart the VM in that case.
792 VM configuration files use a simple colon separated key/value
793 format. Each line has the following format:
800 Blank lines in those files are ignored, and lines starting with a `#`
801 character are treated as comments and are also ignored.
808 When you create a snapshot, `qm` stores the configuration at snapshot
809 time into a separate snapshot section within the same configuration
810 file. For example, after creating a snapshot called ``testsnapshot'',
811 your configuration file will look like this:
813 .VM configuration with snapshot
827 There are a few snapshot related properties like `parent` and
828 `snaptime`. The `parent` property is used to store the parent/child
829 relationship between snapshots. `snaptime` is the snapshot creation
830 time stamp (Unix epoch).
837 include::qm.conf.5-opts.adoc[]
843 Online migrations, snapshots and backups (`vzdump`) set a lock to
844 prevent incompatible concurrent actions on the affected VMs. Sometimes
845 you need to remove such a lock manually (e.g., after a power failure).
849 CAUTION: Only do that if you are sure the action which set the lock is
858 `/etc/pve/qemu-server/<VMID>.conf`::
860 Configuration file for the VM '<VMID>'.
863 include::pve-copyright.adoc[]