Prerequisites 

• XCP/Xenserver

 Utilizing an ISO image in a VM's cdrom drive is fairly easy to do but because of the limited size of the Control Domain's (dom0) operating system partition it's difficult to download ISO images to /opt/xensource/packages/iso and it isn't really recommended to put them there anyway. In this tutorial we'll create a CD repository using an NFS share.

In our example we'll be using a share on the cloud0 host named /media/NFSISO. To set this up on cloud0 you'd log into cloud0 as root and add this line to the /etc/exports file of your NFS server. 

/media/NFSISO/ *(rw)

I'd recommend that you secure your NFS share more tightly than I've done here but for the purpose of this tutorial we'll go with it. We need to make a directory that we can mount our NFS share on first.

[root@cloud1 ~]# mkdir /media/NFSISO

Add the entry to the fstab so it will be mounted on bootup. The following line for this tutorial should be added to the /etc/fstab using your favorite text editor.

cloud0:/media/NFSISO  /media/NFSISO   nfs   defaults 0 0 

Mount the NFS share and verify it's mounted using df.

[root@cloud1 ~]# mount /media/NFSISO/
[root@cloud1 ~]# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1              4128448   2012164   1906572  52% /
none                    524444         0    524444   0% /dev/shm
cloud0:/media/NFSISO  20642428    176200  19417652   1% /media/NFSISO

Create the iso Storage Repository using the /media/NFSISO location. 

xe sr-create name-label="NFS ISO" type=iso \
 device-config:location=/media/NFSISO/ device-config:legacy_mode=true \
 content-type=iso

Verify using xe sr-list.

[root@cloud1 ~]# xe sr-list type=iso
uuid ( RO)                : 5dddd3c4-96bf-e316-2c84-8f4c80684d31
          name-label ( RW): NFS ISO
    name-description ( RW): 
                host ( RO): cloud1.acs.edcc.edu
                type ( RO): iso
        content-type ( RO): iso

Now we need to download an ISO disk for use in a VM. For this purpose we'll download the CentOS 6.3 Live DVD. CD into your new Storage Repository directory (/media/NFSISO) and use wget to download the iso file. 

[root@cloud1 ~]# cd /media/NFSISO
[root@cloud1 NFSISO]# wget \
 http://mirror.flhsi.com/centos/6.3/isos/x86_64/CentOS-6.3-x86_64-LiveDVD.iso
[root@cloud1 NFSISO]# xe sr-scan uuid=5dddd3c4-96bf-e316-2c84-8f4c80684d31

Verify that XCP sees it using xe cd-list. 

[root@cloud1 NFSISO]# xe cd-list
uuid ( RO)          : 0549c68a-e38d-4cd8-9974-ba0b9167ff5a
    name-label ( RW): CentOS-6.3-x86_64-LiveCD.iso

Now that the CD ISO file shows up you can attach it to a VM.