XenServer VM creation

As I promised earlier. If you want to create a new virtual machine in XenServer or XCP from an ISO file in the CLI and don't want to download it on-the-fly, here are the steps you should take.
Let's assume that you have only one 650megs cd image. Your 4 gigs size root fs will be enough to host that. If you have a dvd image or you want to store more then one cd image, it won't fit. Then, you have to create a new partition with LVM tools. So:
lvcreate -L15G -n /dev/VG_XenStorage-[PRESS_TAB_HERE]/MYISOS
mkfs.ext3 /dev/VG_XenStorage-[PRESS_TAB_HERE]/MYISOS
mkdir -p /myfiles/ && mount /dev/VG_XenStorage-[PRESS_TAB_HERE]/MYISOS /myfiles
Having done, here is the second step. Create a new Storage Repository.
xe sr-create name-label=MY-LITTLE-SR type=iso device-config:location=/myfiles/ device-config:legacy_mode=true content-type=iso
You'll see something like this cd0423d8-23db-5af4-bd70-43b60c901e17
That's the UUID of your newly created storage. Now, copy your install iso file, from example from an USB key:
cp /mnt/sdc1/CentOS-6.0-x86_64-LiveCD.iso /myfiles/
xe sr-scan uuid=cd0423d8-23db-5af4-bd70-43b60c901e17
xe cd-list 
(always use TAB!). The reply is:

 xe vm-install template=Other\ install\ media new-name-label=MY-LITTLE-VM sr-uuid=$(xe sr-list name-label="Local storage" --minimal)
a69f7844-1c4f-7e44-e072-978de5c1788c

That means you have succesfully created your VM on the disk storage named Local storage. (Default place to put VM's on.). Let's create a virtual interface for this machine and bind it to the physical interface eth0.
xe vif-create network-uuid=$(xe network-list name-label="Pool-wide network associated with eth0" --minimal) vm-uuid=$(xe vm-list name-label=MY-LITTLE-VM --minimal) device=0
It's time to create a new 25Gigs virtual disk and mount it to the VM as a Virtual Block Device.
xe vdi-create name-label=root-MY-VM sr-uuid=$(xe sr-list name-label="Local storage" --minimal) type=system virtual-size=25GiB sharable=false
xe vdb-create vdi-uuid=$(xe vdi-list name-label=root-MY-VM --minimal) vm-uuid=$(xe vm-list name-label=MY-LITTLE-VM --minimal) type=Disk bootable=true device=0
So far so good. Now, load the CD and set a new fixed RAM size, overwriting the template setting.
xe vm-cd-add vm=MY-LITTLE-VM cd-name=CentOS-6.0-x86_64-LiveCD.iso device=1
xe vm-memory-limits-set vm=MY-LITTLE-VM static-min=512MiB static-max=512MiB dynamic-min=512MiB dynamic-max=512MiB

To delegate a virtual quad-core vCPU to the VM: 
xe vm-param-set platform:cores-per-socket=4 uuid=$(xe vm-list name-label=MY-LITTLE-VM --minimal)
or set the max virtual CPUs number to 8. (That's the number that a physical quad-core can drive)
xe vm-param-set VCPUs-max=8 uuid=$(xe vm-list name-label=MY-LITTLE-VM --minimal)

Now, fire up the VM and switch to its console:
xe vm-start name-label=MY-LITTLE-VM
xe console vm=MY-LITTLE-VM
Exit the console with: CTRL+5

Sometimes it is useful to identify your virtual network cards VIFs in connection with your VMs. Remember this command:
xe vm-list is-control-domain=false params=dom-id,name-label,uuid
It will tell your VMs' domain IDs. Just watch your ifconfig output and match the VIFs' IDs (vifx.y) to your VM domains' IDs. (x is your VM, y is the device number.)
While investigating which damn vlan, bridge, vif or whatever interface bound to what and where, this is the MOST USEFUL command I've ever seen:
brctl show