In this article, I will show you how to install (any) operating system via command line in Citrix Xen. And without too much comment, read on!

Create a VM from the Debian Lenny template. Output should be the VM's UUID:

xe vm-install template="Debian Wheezy 7.0 (64-bit)" new-name-label=debian

Execution:

[root@xenGZ cd]# xe vm-install template="Debian Wheezy 7.0 (64-bit)" new-name-label=debian
36f3763b-4011-055f-4945-92fe13a0027b

Get the root disk UUID of this new VM:

xe vbd-list vm-uuid=<vm_uuid> userdevice=0 params=uuid --minimal

Execution:

[root@xenGZ cd]# xe vbd-list vm-uuid=36f3763b-4011-055f-4945-92fe13a0027b userdevice=0 params=uuid --minimal
20b45191-8a7c-1c97-8995-8b1776866965

Using the UUID from the previous command, remove the bootable option from it:

xe vbd-param-set uuid=20b45191-8a7c-1c97-8995-8b1776866965 bootable=false

Execution:

[root@xenGZ cd]# xe vbd-param-set uuid=20b45191-8a7c-1c97-8995-8b1776866965 bootable=false
[root@xenGZ cd]#

List the name of the CD drives:

xe cd-list

Execution:

[root@xenGZ cd]# xe cd-list
uuid ( RO)          : f5875157-4df4-4ed3-88d6-00edd28375e4
    name-label ( RW): Old version of xs-tools.iso

uuid ( RO)          : f341651f-ded7-4e6b-9751-2f7e12725edb
    name-label ( RW): Old version of xs-tools.iso

uuid ( RO)          : cd64bfa2-457c-475a-8d84-2489f744e2c7
    name-label ( RW): xs-tools.iso

uuid ( RO)          : 8fd5825b-c65c-4065-b7be-58c126900fc8
    name-label ( RW): Old version of xs-tools.iso

uuid ( RO)          : e365d863-72a6-44ab-b62b-f73006bef547
    name-label ( RW): Old version of xs-tools.iso

uuid ( RO)          : 23a79add-fd2c-476e-9df7-fd45d738f8cc
    name-label ( RW): Old version of xs-tools.iso

uuid ( RO)          : acf6edec-c22a-448e-8d89-73a8f1e2d572
    name-label ( RW): Old version of xs-tools.iso

uuid ( RO)          : 27e7f532-4aaa-4dd3-825f-3b84c5b04855
    name-label ( RW): XenCenter.iso

uuid ( RO)          : 758ec20a-ce4a-481f-a582-1316c30101f7
    name-label ( RW): debian-8.2.0-amd64-CD-1.iso

Add the desired CD-ROM to the VM:

NOTE: if device number is occupied, try a higher number.
xe vm-cd-add vm=<vm_name> cd-name="<host_cd_drive_name_label>" device=<number>

Execution:

[root@xenGZ cd]# xe vm-cd-add vm=debian cd-name="debian-8.2.0-amd64-CD-1.iso" device=3
[root@xenGZ cd]#

Get the UUID of the VBD corresponding to the CD drive added previously:

xe vbd-list vm-uuid=<vm_uuid> type=CD params=uuid --minimal

Execution:

[root@xenGZ cd]# xe vbd-list vm-uuid=36f3763b-4011-055f-4945-92fe13a0027b type=CD params=uuid --minimal
41973dba-dece-0193-fa58-448837f85b6a

Make the virtual CD bootable:

xe vbd-param-set uuid=<cd_drive_uuid> bootable=true

Execution:

[root@xenGZ cd]# xe vbd-param-set uuid=41973dba-dece-0193-fa58-448837f85b6a bootable=true
[root@xenGZ cd]#

Configure the install repository as CD drive:

xe vm-param-set uuid=<vm_uuid> other-config:install-repository=cdrom

Execution:

[root@xenGZ cd]# xe vm-param-set uuid=36f3763b-4011-055f-4945-92fe13a0027b other-config:install-repository=cdrom
[root@xenGZ cd]#

Add and configure network adapter:

xe network-list
xe vif-create vm-uuid=<vm_uuid> network-uuid=<network_uuid> mac="<new_mac_address>" device=0
Note: if you do not specify the mac, the system will choose one automatically.

If needed, resize disk before proceeding:

xe vm-disk-list vm=debian
xe vdi-resize uuid=<vdi_uuid> disk-size=<new_size_in_GiB>

Start the VM:

[root@xenGZ cd]# xe vm-start vm=debian
[root@xenGZ cd]#

Connect to VM's VNC via SSH Tunneling (without XenCenter):

xe vm-list params=dom-id,resident-on name-label=<vm>
xenstore-read /local/domain/<dom-id>/console/vnc-port

Execution:

[root@xenGZ cd]# xe vm-list params=dom-id,resident-on name-label=debian
resident-on ( RO)    : 3664c511-cd7b-4705-8fcb-31f8b82d46d5
         dom-id ( RO): 14

[root@xenGZ cd]# xenstore-read /local/domain/14/console/vnc-port
5904

Create a tunnel from your machine to XEN via ssh:

ssh -L 7777:localhost:5904 root@xen_ip

Now use your favorite VNC client and connect to localhost:7777.
You should have the debian installer displayed.

After the installation remove the boot from cd and enable one from disk:

[root@xenGZ ~]# xe vm-shutdown vm=debian
[root@xenGZ ~]# xe vbd-param-set uuid=41973dba-dece-0193-fa58-448837f85b6a bootable=false
[root@xenGZ ~]# xe vbd-param-set uuid=20b45191-8a7c-1c97-8995-8b1776866965 bootable=true

That is pretty much it. Enjoy!