P2V - physical to virtual

From regional-training

Sometimes you would like to take a copy of a physical machine and preserve it as a VM so you can archive it, or even run it on upgraded hardware.

P2V

dependencies

On the virt-v2v host conversion machine:

  • install prequisites
apt install lib-virt
apt install libguestfs-tools
  • make the following link so v2v tools work
ln -s /usr/share/ /share

virtio-win

Windows virtio drivers are para-virtualized drivers to make VM disks more efficient. The virtio-win package (if available, e.g. for redhat or fedora) installs a CD-ROM image, virtio-win.iso, in the 

/usr/share/virtio-win/

(Note that directory is denied by appamor so move the .iso somewhere else e.g. /virtual/iso/)

These virtio devices can be used to improve the performance of your Windows quest VMs: 

wget https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-virtio/virtio-win-0.1.185-2/virtio-win-0.1.185.iso

create a bootable image

On the v2v host:

  • ensure we have spare disk capacity for the KVM virtual disk (I inserted /dev/sdd).
lsblk
  • Insert a USB drive, identify its device
lsblk

NAME            MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda               8:0    0 931.5G  0 disk 
├─sda1            8:1    0  15.4G  0 part [SWAP]
└─sda2            8:2    0 916.1G  0 part 
  └─hdd-storage 254:2    0 916.1G  0 lvm  /hdd
sdb               8:16   0 111.8G  0 disk 
├─sdb1            8:17   0   487M  0 part /boot/efi
├─sdb2            8:18   0   954M  0 part 
├─sdb3            8:19   0  28.9G  0 part 
│ └─os-root     254:0    0  28.9G  0 lvm  /
└─sdb4            8:20   0  81.5G  0 part 
  └─ssd-storage 254:1    0  81.5G  0 lvm  /ssd
sdc               8:32   1  14.5G  0 disk 
└─sdc1            8:33   1  14.5G  0 part 
sdd               8:48   0   3.7T  0 disk 
└─sdd1            8:49   0   3.7T  0 part /mnt/sdd1
  • create bootable p2v image
virt-p2v-make-disk -o /dev/sdc ubuntu-16.04

Note: I could not get Debian 10 to boot, will try Debian 8 later since they changed boot images at 10 and legacy systems got left out. When targetting a device choose one that is not too large because the script resizes the image to use the whole drive, which can be very slow, particularly with large USB drives or even slow thumb drives.

The p2v boot image on the USB drive will be used to boot the Windows physical machine to initiate the transfer of the Windows disk images to a KVM guest via ssh shell communications with the target v2v server (where you must have installed the above packages).

Note: I installed the virtualisation software on padme, since padme already had an sshd server established. I just mounted an external USB HDD (with sufficient capacity) to contain the target guest virtual disk, which can then moved somewhere else and executed in lib-virt e.g. using virt-manager on c3po. That way I do not pollute c3po with an sshd server, nor do I have to make a bridge network to any of c3po's running guest VMs that have an sshd server which I could have used instead.

You may also choose use root sshd login if your v2v server needs access to weirdly mounted file systems. In which case some security modifications are necessary: 

vi /etc/ssh/sshd_config

PermitRootLogin=yes

Don't forget to disable root ssh login after you are all done, and use a really complex unknown password. It also helps that padme's sshd port 22 is not exposed to the www.

conversion

On the client machine:

  • Insert the bootable USB drive in your physical system and configure boot via boot menu (F12 on Dell equipment, F2 and F11 on others).
  • fill out the target server credentials:
server: padme  port : 22
user: root password: <something-really-obscure>
storage: /mnt/sdx/p2v
  • select the drives to convert (deselect the cdrom)
  • test the connection
test
  • start the conversion and transfer process:
next

Other reading

how to repair grub

monitoring

On the v2v server:

  • install some utils
apt install sysstat iftop
  • monitor the network
iftop -i <ifname>
  • monitor disk
iostat 60
  • monitor the logs
tail -f /tmp/p2v-date-guid/*log.txt
  • monitor the target files
for (( ; ; )) do ls -lrtah /mnt/sdX/p2v; sleep 60; done

Alternative ideas for Microsoft Windows conversions

HyperV

Note: I could not get this to work on the Windows 7 machine, it complained about being unable to access disk 0.

disk2vhd

VMWare

Use VMWareConverter to convert a live physical machine to a VMWare VM image.

Note: In Windows Vista and later versions, Microsoft switched to using a separate boot partition. In these VMs, typically /dev/sda1 is the boot partition and /dev/sda2 is the main (C:) drive. Resizing the first (boot) partition causes the bootloader to fail with 0xC0000225 error. Resizing the second partition (ie. C: drive) should work.

For Windows 7 and 8, see also

virt-v2v

You may use virt-v2v to convert a source VM to a target VM.

requirements

  • a temorary area that is large enough
    • (default) /var/tmp
    • mode must be 700
  • else mount a tmp on a different ext4 filesystem and set TMPDIR to point to it ensuring mode is 700
  • an attached drive large enough to contain the converted VM images

See:

e.g. converting vmdk to qcow2

Note: qcow2 disks are thin provisioned and only take up the space they require; this means they will expand as more extents are added to the filesystem that overlays their image.

  • run
cd /mnt/ext/VM/port-ralph
export TMPDIR=/mnt/ext/tmp
virt-v2v --verbose -i disk -if vmdk port-ralph.vmdk -o local -oa sparse -of qcow2 -os . -on port-ralph-v2v.qcow2

Note that $TMPDIR has more space available than /var/tmp.

Output is: 

[   0.1] Opening the source -i disk -if vmdk port-ralph.vmdk
[   0.1] Creating an overlay to protect the source from being modified
[   0.2] Initializing the target -o local -os .
[   0.2] Opening the overlay
[  10.2] Inspecting the overlay
[  11.9] Checking for sufficient free disk space in the guest
[  11.9] Estimating space required on target for each disk
[  11.9] Converting Windows 7 Home Premium to run on KVM
virt-v2v: warning: Neither rhev-apt.exe nor vmdp.exe can be found.  Unable 
to install one of them.
virt-v2v: warning: there are no virtio drivers available for this version 
of Windows (6.1 x86_64 Client).  virt-v2v looks for drivers in 
/usr/share/virtio-win

The guest will be configured to use slower emulated devices.
virt-v2v: This guest does not have virtio drivers installed.
[  13.9] Mapping filesystem data to avoid copying unused and blank areas
[  15.6] Closing the overlay
[  15.8] Checking if the guest needs BIOS or UEFI to boot
[  15.8] Assigning disks to buses
[  15.8] Copying disk 1/1 to ./port-ralph-v2v.qcow2-sda (qcow2)

 qemu-img convert -f vmdk port-ralph.vmdk -O qcow2 port-ralph.qcow2
  • then in-situe adjustments
virt-v2v -i local -if qcow2 port-ralph.qcow2 --in-place

Disk cloning

Don't forget the simplest: disk cloning.

You can clone the machine's disks and attachment them as a VM disks and execute the image with qemu-systemXXX - see cloning

A completely cloned disk can be executed via qemu and associated with a virt-manager image. 

qemu-img convert -p -O raw /dev/sda /srv/vm/mywindowsinstall/disk.raw
qemu-img resize /srv/vm/mywindowsinstall/disk.raw +50G
  • running the clone (for a 64 bit Intel, 8G RAM, 8 vcpus):
qemu-system-x86_64 -drive file=disk.raw,format=raw,index=0,media=disk -soundhw es1370 -vga cirrus -m 8G -smp 8
  • this is what I used for a Windows 7 image
qemu-system-x86_64 -drive file=w7.raw,format=raw,index=0,media=disk -soundhw es1370 -vga cirrus -m 16G -smp cpus=8,cores=8

downsizing a VM qcow2 or vmdk file

This article https://www.qemu.org/docs/master/system/images.html explains the qemu supported images; e.g. it is not necessary to connvert vmdlk to qcow2 as both formats are supported. Note that raw format on an ext4 file system is much more performance, and ext4 supports holes, so the resulting raw format will be sparse. qcow2 provides compression and is sparse on any file-system, including windows - but is less efficient.

The following describes how to shrink sparse disk images and their contained file systems.

user suggestions, the manual, less downtime way

The VM is online while zero-fill unallocated extents of the disk image, then taken offline to shrink the dfisk image:

the more automatic, albiet longer downtime way

The VM must be taken offline to perform these steps, the first of which is to copy the original disk image and then zero fill the unallocated spaces:

resizing boot partitions

In Windows Vista and later versions, Microsoft switched to using a separate boot partition. In these VMs, typically /dev/sda1 is the boot partition and /dev/sda2 is the main (C:) drive. Resizing the first (boot) partition causes the bootloader to fail with 0xC0000225 error. Resizing the second partition (ie. C: drive) should work.

References

Some casual reading, but most of it has been worked out and documented in my cookbook recipes above:

categories

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