The Perfect Xen 3.1.0 Setup For Debian Etch (i386) - Page 3
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4.2 Creating Virtual Machines (domU)
We will use xen-tools to create virtual machines. xen-tools make it very easy to create virtual machines - please read this tutorial to learn more: https://www.howtoforge.com/xen_tools_xen_shell_argo. xen-tools are available as a Debian Etch package, so we install that one right now:
apt-get install xen-tools
Next we edit /etc/xen-tools/xen-tools.conf. This file contains the default values that are used by the xen-create-image script unless you specify other values on the command line. I changed the following values and left the rest untouched:
vi /etc/xen-tools/xen-tools.conf
[...] gateway = 192.168.0.1 netmask = 255.255.255.0 passwd = 1 kernel = /boot/vmlinuz-2.6.18-xen #initrd = /boot/initrd.img-2.6.16-2-xen-686 mirror = http://ftp2.de.debian.org/debian/ [...] |
Please make sure that you comment out the initrd line! At least on my installations I've never needed a ramdisk for virtual machines.
The passwd = 1 line makes that you can specify a root password when you create a new guest domain. In the kernel line you must specify the domU kernel that you want to use for your guest domains. In the mirror line specify a Debian mirror close to you.
Make sure you specify a gateway and netmask. If you don't, and you don't specify a gateway and netmask on the command line when using xen-create-image, your guest domains won't have networking even if you specified an IP address!
Now let's create our first guest domain, xen1.example.com, with the IP address 192.168.0.101:
xen-create-image --hostname=xen1.example.com --size=2Gb --swap=256Mb --ide \
--ip=192.168.0.101 --netmask=255.255.255.0 --gateway=192.168.0.1 --force \
--dir=/vserver --memory=32Mb --arch=i386 --kernel=/boot/vmlinuz-2.6.18-xen \
--debootstrap --dist=etch --mirror=http://ftp2.de.debian.org/debian/ --passwd
A lot of switches are unnecessary here because we specified the same details in /etc/xen-tools/xen-tools.conf but it shows that you can specify the desired settings either on the command line or in /etc/xen-tools/xen-tools.conf. Please make sure that you specify --ide, otherwise your virtual machine might not boot!
(To learn more about the available options, take a look at the xen-create-image man page:
man xen-create-image
)
The xen-create-image command will now create the xen1.example.com virtual machine for us. This can take a few minutes. The output should be similar to this one:
server1:~# xen-create-image --hostname=xen1.example.com --size=2Gb --swap=256Mb --ide \
> --ip=192.168.0.101 --netmask=255.255.255.0 --gateway=192.168.0.1 --force \
> --dir=/vserver --memory=32Mb --arch=i386 --kernel=/boot/vmlinuz-2.6.18-xen \
> --debootstrap --dist=etch --mirror=http://ftp2.de.debian.org/debian/ --passwd
General Infomation
--------------------
Hostname : xen1.example.com
Distribution : etch
Fileystem Type : ext3
Size Information
----------------
Image size : 2Gb
Swap size : 256Mb
Image type : sparse
Memory size : 32Mb
Kernel path : /boot/vmlinuz-2.6.18-xen
Networking Information
----------------------
IP Address 1 : 192.168.0.101
Netmask : 255.255.255.0
Gateway : 192.168.0.1
WARNING
-------
Loopback module not loaded and you're using loopback images
Run the following to load the module:
modprobe loop loop_max=255
Creating swap image: /vserver/domains/xen1.example.com/swap.img
Done
Creating disk image: /vserver/domains/xen1.example.com/disk.img
Done
Creating ext3 filesystem on /vserver/domains/xen1.example.com/disk.img
Done
Installing your system with debootstrap mirror http://ftp2.de.debian.org/debian/
Done
Running hooks
Done
No role script specified. Skipping
Creating Xen configuration file
Done
Setting up root password
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
All done
Logfile produced at:
/var/log/xen-tools/xen1.example.com.log
server1:~#
(You can ignore this warning:
WARNING
-------
Loopback module not loaded and you're using loopback images
Run the following to load the module:
modprobe loop loop_max=255
The virtual machine will work nevertheless.)
There should now be a xen1.example.com configuration file - /etc/xen/xen1.example.com.cfg. Take a look at it to become familiar with virtual machines configuration files:
cat /etc/xen/xen1.example.com.cfg
# # Configuration file for the Xen instance xen1.example.com, created on # Mon May 28 20:53:05 2007. # # # Kernel + memory size # kernel = '/boot/vmlinuz-2.6.18-xen' memory = '32' # # Disk device(s). # root = '/dev/hda1 ro' disk = [ 'file:/vserver/domains/xen1.example.com/disk.img,hda1,w', 'file:/vserver/domains/xen1.example.com/swap.img,hda2,w' ] # # Hostname # name = 'xen1.example.com' # # Networking # vif = [ 'ip=192.168.0.101' ] # # Behaviour # on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' |
To start the virtual machine, run
xm create /etc/xen/xen1.example.com.cfg
Run
xm console xen1.example.com
to log in on that virtual machine (type CTRL+] if you are at the console, or CTRL+5 if you're using PuTTY to go back to dom0), or use an SSH client to connect to it (192.168.0.101).
To get a list of running virtual machines, type
xm list
The output should look like this:
server1:~# xm list
Name ID Mem VCPUs State Time(s)
Domain-0 0 301 1 r----- 1191.0
xen1.example.com 1 32 1 -b---- 50.6
server1:~#
To shut down xen1.example.com, do this:
xm shutdown xen1.example.com
If you want xen1.example.com to start automatically at the next boot of the system, then do this:
ln -s /etc/xen/xen1.example.com.cfg /etc/xen/auto
Here are the most important Xen commands:
xm create -c /path/to/config - Start a virtual machine.
xm shutdown <name> - Stop a virtual machine.
xm destroy <name> - Stop a virtual machine immediately without shutting it down. It's as if you switch off the power button.
xm list - List all running systems.
xm console <name> - Log in on a virtual machine.
xm help - List of all commands.
Let's create a second vm, xen2.example.com with the IP address 192.168.0.102:
xen-create-image --hostname=xen2.example.com --size=2Gb --swap=256Mb --ide \
--ip=192.168.0.102 --netmask=255.255.255.0 --gateway=192.168.0.1 --force \
--dir=/vserver --memory=32Mb --arch=i386 --kernel=/boot/vmlinuz-2.6.18-xen \
--debootstrap --dist=etch --mirror=http://ftp2.de.debian.org/debian/ --passwd
Afterwards, you can start xen2.example.com like this:
xm create /etc/xen/xen2.example.com.cfg
and shut it down like this:
xm shutdown xen2.example.com
A list of all virtual machines that were created with the xen-create-image command is available under
xen-list-images
server1:~# xen-list-images
Name: xen1.example.com
Memory: 32
IP: 192.168.0.101
Name: xen2.example.com
Memory: 32
IP: 192.168.0.102
server1:~#
To learn more about what you can do with xen-tools, take a look at this tutorial: https://www.howtoforge.com/xen_tools_xen_shell_argo
