How-To: Converting Xen Linux VMs to VMWare ESXi
I have a couple Linux VMs I created on Xen using xen-create-image (as such, they are using pygrub and have one virtual disk file per partition). Now I want to migrate those over to a VMWare ESXi box. To convert your raw Xen disk images to VMWare vmdk files, do this:
1. In VMWare Fusion or Workstation, do a basic install of Debian Squeeze onto a flat-file (not split into 2GB segments and preallocated) VMDK that is slightly larger than your virtual Xen disk with a separate VMDK for swap.
2. Downgrade it to Grub 1 using apt-get install grub-legacy, grub-install /dev/sda, update-grub (as Grub 2 is not compatible with /boot/grub/menu.lst files as generated by xen-create-image).
3. Shut down and make a copy of the VMDK.
4. Boot the VM back up and re-install Grub2 using apt-get install grub.
5. Edit /boot/grub/grub.cfg and replace root=UUID=xxxxxxxxxx in the linux lines with root=/dev/sda1
6. Shut down the VM and attach the VMDK you copied in step 3 as an additional disk (this will be the target disk for our conversion).
7. Boot it up and make sure that you’re getting a Grub2 screen (i.e. it is not booting from the copied VMDK).
8. Using mount, check that your root disk is sda1 (which usually should be the first disk, not the copied disk). Using ls /dev/sd*, make sure it sees the target disk as sdc.
9. dd if=/path/to/xen/vm/disk.img of=/dev/sdc1 bs=1048576
10. mount /dev/sdc1 /mnt; cd /mnt
11. nano etc/fstab: replace swap disk /dev/xvda1 with /dev/sdb1 and root disk /dev/xvda2 with /dev/sda1
12. nano etc/inittab: replace hvc0 with tty1
13. nano boot/grub/menu.lst: replace /dev/xvda2 with /dev/sda1
14. umount /mnt
15. Attach the new virtual disk to a VM and boot a rescue system. There, drop to a shell on /dev/sda1 and apt-get update, apt-get install grub
16. Reboot
17. Done!
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Миграция виртуальной машины с XenServer на VMware ESXi 6
Ранее в блоге упоминал про миграцию машин с одного XenServer на другой XenServer. Теперь подошёл к вопросу миграции с XenServer на ESXi. В процессе столкнулся с некоторыми ошибками, расскажу об их решении.
Самым доступным и простым способом оказался инструмент VMware vCenter Converter Standalone. Скачать можно на оф. сайте (через регистрацию). Данный способ сильно облегчает жизнь и позволяет производить миграции почти в автоматическом режиме.
Так выглядит основное окно программы, запускать можно с любой машины (не обязательно с Guest OS):
Для конвертации, нужно нажать “Convert machine” и указать исходную машину с Linux:
И после доступы до гипервизора с ESXi:
На следующем шаге предоставляется возможность выбора Data Store для будущей виртуальной машины:
И в заключении также дается более детальная настройка параметров. Например, для разных дисков можно указать разные Storage:
На последнем шаге можно выбрать, что делать с исходной машиной и машиной, которая будет скопирована: например, выключить после завершения миграции.
При использовании vCenter Converter Standalone версии 6.2.0, в самом конце миграции возникает ошибка (Red Hat Enterprise Linux 7.6 или CentOS 7.6) на 98%:
An error occurred during the conversion: 'SysCommandWrapper: Error encountered in SysCommand: SysCommand failed to wait /usr/lib/vmware-converter/chrootAndExec.sh to terminate. Решается она даунгрейдом пакетов:
yum downgrade lvm2-libs-2.02.180-10.el7_6.2.x86_64 lvm2-2.02.180-10.el7_6.2.x86_64 device-mapper-event-libs-1.02.149-10.el7_6.2.x86_64 device-mapper-1.02.149-10.el7_6.2.x86_64 device-mapper-libs-1.02.149-10.el7_6.2.x86_64 device-mapper-event-1.02.149-10.el7_6.2.x86_64А после миграции yum update вышеописанных пакетов.
На оф. сайте есть информация по другим ошибкам.
После успешной миграции столкнулся с непонятной особенностью. Смигрировалось всё без ошибок, но при старте уже в ESXi, вылезает окно с ошибкой startup cannot find command ‘:’. Пока не нажмешь “q”, ОС не загрузится. Возникает это из-за кривых правок файла /etc/grub2.cfg, где фигурируют символы “: #”, когда должен быть только знак комментариев – “#”. Для исправления открыть файл в редакторе Vim (или любым другим удобным) и выполнить замену всех двоеточий и пробелов между решёток на одиночную решетку :
Теперь при следующем ребуте загрузка будет без этих непонятных ошибок.
И в конце осталось только удалить XenServer Tools и установить VMware-tools:
yum remove xen* && yum install open-vm-toolsПроверить установленную версию можно командой:
Если ошибка unable to query the live linux source machine, при этом логин-пароль верные, стоит проверить подробный лог – мне помогла остановка Docker на исходной машине.
Также решение по проблемам с description = “GrubInstaller::InstallGrub: /usr/lib/vmware-converter/installGrub.sh failed with return code: 127, and message:
/vmware-updateGrub.sh: 38: grub: not found
Thread: Converting Linux Xen guests to VMWare
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Converting Linux Xen guests to VMWare
At work, I have been tasked with migrating our existing Xen Linux guests (RH on RH) to a new VMWare environment.
Since I have yet to find a very comprehensive procedure, I thought I’d write one.
This is a work in progress and as I fine tune the procedure I will update, but for those needing to do it, this should work for you:
How to Convert a Xen Linux Guest to VMWare
These are the high level to-do’s that are ahead of you. Please do not use this part of the guide to do the conversion, it is only a synapses of what you are in for.
Step 1: prep the source Xen guest for remote root/password access
Step 2: run the VMWare conversion process (confirm “new” disks are up to new standards)
Step 3: change nic to vmxnet3 in new VMWare guest settings
Step 4: boot the newly created VMWare guest off a Linux live CD; configure network
Step 5: mount converted file systems; chroot into this environment
Step 6: edit inittab; modprobe.conf
Step 7: install non-xen kernel version insuring the SAME kernel version
Step 8: edit grub.conf
Step 9: install vmware tools
Step 10: fix remote root/password access; reboot
Step 11: test test test. re-test.
Tools you need or need access to:
VMWare virtual center with permission to create new guests.
VMWare converter.
Access to Xen source as root.
Access to Linux live CD media (typically already on a data store).
Fairly good knowledge of Linux command line tools and VMWare.
Step 1:
For the conversion process to work, the VMWare converter needs remote root/password access to the Xen guest you are converting.
Change the root password to something new and unique. DO NOT use the default root password during this process.
Note the current xen kernel version for use later.
Step 2:
Access VMWare Converter via client or direct log on to converter server.
Enter hostname, root and password. Feel free to review source machine to insure proper access.
Make sure to convert only those files systems that are required (no NAS mounts for instance).
Make sure NEW file systems adhere to any new or updated policy regarding size. Adjust accordingly.
Select the option to configure the network using a unique IP (unless your server network uses DHCP) and NOT the source machines IP.
IF THIS IS A REAL CONVERSION AND NOT JUST A TEST: Make sure to select the option to power off the source Xen machine (leave the new machine off as well).
Run the conversion process.
Connect to VC, open the console of the new VMWare machine that the conversion process is creating.
NOTE: for some reason (a bug?), the NEW “helper” VM sometimes cannot get on the network on its own. You must log into it as root using the temp password you created on the source Xen machine, and ping something off the network. This will kick start the networking and you should now see the converter doing its thing.
NOTE: In order to access the new «helper» VM that the converter creates, you must first configure the converter itself to allow such a thing, BEFORE you begin this process. I’ll link to those instructions when I find them again. This change will allow you to log into the helper VM using the source Xen credentials.
Enjoy an espresso or two while you wait.
Once done, both the source Xen machine and the new VMWare machine should be powered off automatically.
IF THIS IS A REAL CONVERSION: Disable the source Xen network configuration to insure it doesn’t come back on the network. This process documented elsewhere.
Re-configure the new VMWare machine to use the vmxnet3 nic driver (remove existing e1000 and add a new vmxnet3 nic), and also point the CDROM to a Linux live CD of your choice (I’ll use Fedora in this document).
Also change the boot option delay to at least 10ms (or higher) to make your life easier.
NOTE: The new VMWare guest WILL NOT boot up in its existing condition. This is a known problem we are about to address.
Boot the new VMWare machine via the Linux live CD.
Configure the live CD network with any available IP (the source Xen IP is fine to use here if you are on the same network obviously).
From the Linux live cd, mount the guest file systems (the specifics will depend on what your source Xen machine looked like):
open a terminal:
$ su — (no password is needed on the Fedora live cd)
# mkdir /mnt/server
# mount /dev/mapper/vgroot-lvroot /mnt/server
# mount /dev/sda1 /mnt/server/boot
# mount /dev/mapper/vgroot-lvusr /mnt/server/usr
# mount /dev/mapper/vgroot-lvopt /mnt/server/opt
# mount /dev/mapper/vgroot-lvvar /mnt/server/var
# mount —bind /dev /mnt/server/dev/
chroot into this environment:
#chroot /mnt/server
mount proc:
#mount /proc /proc -t proc
Edit /etc/inittab and comment out the Xen console line:
(At my office, the first getty line is co:blahblahblah, which is the Xen console. You don’t need this so comment it out)
Edit /etc/modprobe.conf to include new scsi driver and vmxnet3 driver:
This is key. Xen uses a different scsi controller than vmware.
Comment out the xenblk line and make sure you have:
alias eth0 vmxnet3 —- the recommended vmware nic driver
alias scsi_hostadapter mptbase —— the recommended vmware scsi adapter
alias scsi_hostadapter1 mptspi —— the recommended vmware scsi adapter
Install non-Xen version of the SAME kernel as the source Xen machine (you can look at /boot and /boot/grub/grub.conf for which kernel if you didn’t note this in Step 1 as instructed):
# yum install kernel-XXXXXXXXXXXX
Edit grub to make this new kernel the default:
default=(what ever line your new non-Xen kernel is
From the VC client, choice to “Install VMWare tools” for this machine.
Mount the CDRom (again, this is from within the chroot’d environment):
# mkdir /media/cdrom
# mount /dev/cdrom /media/cdrom
Explode the vmware-tools installation files:
# tar -zxvf /media/cdrom/YYYYYYYY -C /var/tmp/
run the installer:
# ./vmware-install
You may have to pick a screen size IF x-server is installed on this guest already.
Pick 1024×768 unless you know a reason not to.
fix the sshd config file (if you normally dis-allow remote root access) and change the root password back to the current one.
Test access; test for proper kernel version; test; test; test; test.