Hello everybody!
Watch this video to find out how to install and configure Citrix hypervisor or XenServer,
how to take a snapshot, and how to restore the whole system back to its previous state.
Also, you will see how to recover data from a XenServer virtual machine if it is deleted
by mistake, if it refuses to boot, or if it displays an error at startup that cannot be
fixed.
Citrix Hypervisor (XenServer) is a virtualization platform based on a special version of Linux
and developed by the company called Citrix Systems.
With this platform, you can run a number of virtual machines on a single physical server.
This hypervisor lets you create virtual machines, take snapshots of their disks, and manage
virtual machine workloads.
Just like other virtualization products, it’s by no means perfect, and sometimes there may
be failures or errors resulting in loss of data.
If that’s the case, there’s a question to answer: how to recover the data?
This video will give you the answer, in all detail, how to recover files from a virtual
machine working with Xen hypervisor.
What you need to install Citrix hypervisor For starters, let’s explore how to install
this hypervisor.
There are a few things to be checked before installing XenServer version 8.
It requires a 64-bit Intel VT or AMD-V processor based on x86 architecture.
If you plan to run Windows virtual machines, you need to enable hardware virtualization
technologies - Intel VT or AMD-V in BIOS.
Also, you need to download an installation ISO image from the Citrix website before you
can install the Xen hypervisor.
To do it, go to the Citrix download page.
From the drop-down menu, select Citrix Hypervisor (XenServer), and the choose the latest version,
8.2 LTSR.
You need to register before you can download anything.
How to install Citrix hypervisor 8.2 Add the ISO image to your server with the
remote management console such as IMM, iLO etc, or create a bootable USB drive.
To begin the installation, start the server and boot from the USB drive.
In the GRUB boot menu, choose Install.
At the first stage, choose the keyboard layout to be used and click OK.
At the next step, press F9 if you need to download a special device driver, or click
OK to continue if you don’t need it.
Accept the license agreement – Accept EULA.
Then choose the disk where you want to install Citrix Hypervisor (XenServer).
As I install it from a local disk, I choose “Local media” from the list of sources
and click OK to continue.
When installing from CD/DVD, it is recommended to check the disk; otherwise, skip the check
by clicking ОК.
Set the password for the root account, type it again to confirm, and click OK.
At the next step, you need to configure network parameters, set the automatic or static IP
address, add a subnet and gateway - and finally click OK.
After that, set the host name and configure the DNS server - and click OK when you’re
done.
Select location - click OK, and city - click OK again.
To synchronize time, select NTP and click OK to continue.
Finally, it’s time to hit the button “Install Citrix Hypervisor” to begin the installation.
All the data on the disk will be removed.
At the end of this process, you’ll be offered to install supplemental packs if necessary.
If you don’t need them, click No to complete the installation.
Now that it’s over, remove the installation media and press Enter to reboot.
When the server has booted, you can connect to it from the client PC.
To do it, enter the server’s IP address in the browser: you can find this address
in the hypervisor window.
To manage the server, download and install XenCenter by following this link.
Start the utility and add the server.
Right-click on XenCenter and choose “Add.”
Type the server’s IP address, administrator’s name and password, and click “Add.”
...Then, right-click on the server and choose “Connect.”
Now that you have connected to the server, you can create virtual machines, manage the
host network and its storage and do many other things.
How to connect a local repository To install an operating system for the virtual
machine, you will need an installation disk or ISO file.
I’ll be using an ISO image.
For this purpose, you need to create a repository where ISO images of operating systems will
be stored.
To do that, connect to the server by SSH and create a local folder there by running this
command: mkdir -p /var/opt/xen/ISO_Storage
After that, create a repository with the Store Manager, using another command:
xe sr-create name-label=LocalISO type=iso device-config:location=/var/opt/xen/ISO_Storage
device-config:legacy_mode=true content-type=iso where name-label=LocalISO – is the repository
name When this command is performed, a new storage
will appear in the GUI (graphical user interface) window.
To upload images to the server, connect to it by sftp and copy the image to this folder:
/var/opt/xen/ISO_Storage To activate images, you should browse to LocalISO
- Storage, and hit the “Rescan” button.
After that, the image will appear on the list.
Also, every item initialized in the local repository will be added to the boot list
of the virtual machine.
Now you can select an uploaded image and install it onto a new virtual machine.
How to create a virtual machine To create a virtual machine in XenCenter,
go to the tab New VM.
Select an operating system you’d like to install and click Next.
Give a name for this new virtual machine - Next.
Select installation media, an ISO image from the repository you have created earlier - Next.
Select the server where you would like to create a virtual machine - click Next.
Choose the number of processors and amount of memory to be allocated to this virtual
machine - Next.
After that, set the preferred storage size and click Next; if necessary, add one more
network interface, click Next, and finally click “Create Now” to have the machine
created.
The virtual machine will appear on this list.
When it happens, the machine will start automatically, and the installation of the operating system
will begin.
When you’re through will all typical stages of installation, the virtual machine will
be ready to use.
How to take a snapshot of the virtual machine The Xen hypervisor lets you take snapshots
of your virtual machine.
To create and manage snapshots you need quiet a lot of free space (in fact, more than twice
the size of your virtual machine).
If it happened so that you created a virtual machine on a storage device with a smaller
free space reserve than required, and then decided to take a snapshot, it will occupy
all the free space available.
When you try to remove it, the snapshot will be gone, but you won’t get any free space
back.
A snapshot captures the state of a virtual machine at the specific date and time when
the snapshot was taken.
Such snapshots will help you recover accidentally removed files or system settings that existed
at the time when the snapshot was taken.
To create a snapshot, select a virtual machine, go to the Snapshots tab and click “Take
Snapshot.”
Give the snapshot name, add a description if necessary, and click “Take Snapshot.”
The folder will appear on this list.
How to return to a snapshot To go back to a specific system snapshot,
select it from this list and click “Revert To.”
Check this box if you need a snapshot of the current state of your virtual machine, and
click Yes.
After that, the operating system will roll back to its previous state.
You can find the specific snapshot you need by checking its date and time.
How to recover data from a virtual machine If the virtual machine refuses to boot or
displays an error that can’t be fixed; or if there is a server error - in any of these
cases you can safely use Hetman Partition Recovery to bring your data back.
It supports data recovery from virtual disks of various hypervisors including Citrix Xen.
By default, Citrix XenServer uses LVM storage for its virtual machines.
This storage method has quite a lot of advantages if compared with VHD files, but sometimes
you need to use the file-based storage mode like in VMware ESX, and it may also create
additional difficulties for the recovery process.
When the physical disk containing virtual machine files is connected to the computer,
Hetman Partition Recovery will display all the virtual machine disks.
To see which virtual disks belong to a specific virtual machine, you should run some commands
on the server to find the UUID (Universal Unique Identifier) of the virtual machine,
the UUID of its disk, and the UUID SR (Universal Unique Identifier of the Storage Repository).
To do that, connect to the server by SSH and type the first command:
xe vm-list As a result, you’ve found the virtual machine
UUID; now you can use this identifier to view the connected disks, with the help of this
command: xe vm-disk-list uuid=a9511ac4-4fef-8423-d525-251b8098c130
- in the end, the virtual machine UUID is given.
As a result, you get the virtual disk UUID, which, in its turn, can be used to find the
storage repository UUID.
xe sr-list name-label=Local\ storage Now that we have the repository identifier,
it’s easy to understand to which virtual machine specific disks belong, and you’ll
be able to identify those disks in the data recovery utility.
8087ae69-c195-5e15-8f7f-9ce1558d5cc9.VHD
Connect the server’s disks to a Windows computer, download, install and run the data
recovery tool.
Hetman Partition Recovery will display all virtual machine disks in the Drive Manager.
Choose the disk where the required files used to be stored, right-click on it and select
Open.
Select the scan type - “Fast scan.”
If the “Fast scan” can’t find the required files, then go for “Full analysis.”
Right-click on the disk - “Analyze again” - “Full analysis” - and specify the file
system for this disk - then click Next.
Find the folder where the files were stored, select the files you want to restore, click
“Recovery,” specify the disk and folder where you’d like to save the files, and
click “Recovery” again.
When the entire process is over, you will find the recovered files in the folder you
have chosen.
If the XenServer storage was based on a RAID system, you will need to use Hetman RAID Recovery.
This program will automatically build the RAID with the available disks, and all you
have to do is to run the scan, wait for the results and recover the information.
Hetman RAID Recovery supports the majority of most popular RAID types.
To make your lives easier, our program features the option to search for files by their names.
Also, you’ll be able to preview the file contents to make sure that this is the actual
file you need.
That is all for now!
Hopefully, this video was useful.
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Thank
you for watching.
Good luck.