Why you would want to convert qcow2 to vmdk?
When managing the heterogeneous virtual environment or changing the virtualization solutions that become so common nowadays, you might need to migrate qcow2 from a Linux based KVM virtualization solution to VMWare's proprietary vmdk – the file format in which a VMWare does keep stored it's VMs, especially if you have a small business or work in a small start-up company where you cannot afford to buy something professional as VMware vCenter Converter Standalone or Microsoft virtual machine converter (MVMC)- usually used to to migrate VMware hosts to Hyper-V hosts, but also capable to migrate .qcow2 to .vmdk. The reason is that your old datacenter based on Linux OS custom KVM virtual machines might be moved to VMWare ESX to guarantee better and more systemized management (which though is very questionable, since most of my experiences with VMWare was that though the software was a great one, the people who manage it was not very much specialists in managing it).
Another common reason is that running a separate Linux virtual machine, costs you more than a well organized VMWare farm because you need more qualified Linux specialists to manage the KVMs thus KVM to VMWare management as in most big corporations nowadays’s main target is to cut the costs.
Even with successful migrations like that, though you might often expect a drop in the quality of the service when your VM ends in the VMWare farm.
Nomatter what’s the reason to migrate qcow2 to VMDK So lets proceed with how the .QCOW2 to .VMDK can be easily done.
1. Get information about the VM you would like to migrate to VMDK
In QEMU-KVM environment, the popular image format is qcow2, which outperforms the first generation of qcow format and raw format. You can find the files of virtual disks by checking the information of virtual machine by virsh command:
[root@hypervisor-machine ~]# virsh dominfo virtual-machine-name
INFO
ID: {e59ae416-9314-4e4b-af07-21c31d91b3fb}
EnvID: 1704649750
Name: CentOS7minimal
Description:
Type: VM
State: stopped
OS: centos7
Template: no
Uptime: 00:00:00 (since 2019-04-25 13:04:11)
Home: /vz/vmprivate/e39ae416-9314-4e4b-af05-21c31d91b3fb/
Owner: root@.
GuestTools: state=not_installed
GuestTools autoupdate: on
Autostart: off
Autostop: shutdown
Autocompact: off
Boot order: hdd0 cdrom0
EFI boot: off
Allow select boot device: off
External boot device:
On guest crash: restart
Remote display: mode=manual port=6903 address=0.0.0.0
Remote display state: stopped
Hardware:
cpu sockets=1 cpus=2 cores=2 VT-x accl=high mode=64 ioprio=4 iolimit='0'
memory 2048Mb
video 32Mb 3d acceleration=off vertical sync=yes
memory_guarantee auto
hdd0 (+) scsi:0 image='/vz/vmprivate/e59ae415-9314-4e4b-af05-21c31d91b3fb/harddisk.hdd' type='expanded' 5120Mb subtype=virtio-scsi
cdrom0 (+) scsi:1 image='/home/CentOS-7-x86_64-Minimal-1611.iso' state=disconnected subtype=virtio-scsi
usb (+)
net0 (+) dev='vme42bef5f3' network='Bridged' mac=001C42BEF5F3 card=virtio ips='10.50.50.27/255.255.255.192 ' gw='10.50.50.1'
SmartMount: (-)
Disabled Windows logo: on
Nested virtualization: off
Offline management: (-)
Hostname: kvmhost.fqdn.com
2. Convert the harddrive to VMDK
[root@hypervisor-machine e59ae415-9314-4e4b-af05-21c31d91b3fb]# ls -lsah
1.3G -rw-r—– 1 root root 1.3G Apr 25 14:43 harddisk.hdd
a. Converstion with qemu:
You can use qemu-img tool that is installable via cmds:
yum install quemu-img / apt install qemu-img / zipper install qemu-img (depending on the distribution RedHat / Debian / SuSE Linux)
-f: format of the source image
-O: format of the target image
[root@hypervisor-machine ~]# qemu-img convert -f qcow2 -O vmdk \-o adapter_type=lsilogic,subformat=streamOptimized,compat6 harddisk.hdd harddisklsilogic.vmdk
[root@ hypervisor-machine e59ae415-9314-4e4b-af05-21c31d91b3fb]# ls -lsah
1.3G -rw-r—– 1 root root 1.3G Apr 25 14:43 harddisk.hdd
536M -rw-r–r– 1 root root 536M Apr 26 14:52 harddisklsilogic.vmdk
3. Upload the new harddrive to the ESXi Hypervisor and adapt it to ESX
This vmdk might not be able to used on ESXi, but you can use it on VMware Workstation. To let it work on ESXi, you need to use vmkfstools to convert it again.
a. Adapt the filesystem to ESXi
[root@hypervisor-machine ~]# vmkfstools -i harddisklsilogic.vmdk -d thin harddisk.vmdk
4. Create a VM and add the converted harddrive to the machine.
Futher
Recreate the initramfs
But of course this won’t work directly as it often happens with Linux 🙂 !!.
We need to make adjustments to the virtual machine as well with few manual interventions:
1. Start the machine from the VMWare interface
2. Grub CentOS Linux rescue will appear from the prompt
3. Run command
dracut –regenerate-all –force
to Recreate the initramfs.
Note that You might also have to edit your network configuration since your network device usually get’s a different name.
Finally reboot the host:
[root@hypervisor-machine ~]# reboot
And voila you’re ready to play the VM inside the ESX after some testing, you might switch off the KVM Hypervisor hosted VM and reroute the network to point to the ESX Cluster.
