The most annoying part of xcp-ng is that there’s no way to upload an installation disk image to the hypervisor to actually set up the first virtual machine. Far as I can tell, one is expected to set up a separate iSCI host to hold all the various disk images and ISOs needed; or, which is what I’ll do later, set up an NFS share to share the ISOs across multiple hypervisor hosts.

But that’ll happen after I set up a separate box to run that NFS share. The plan is for it to be some sort of minimal management server running some tiny OS off a battery backup with out-of-band secondary access. Seems like that’s the ideal setup to reliably bootstrap a hypervisor in a (presumed) unreliable, remote environment. Especially if it and the hosts are configured with a boot-on-lan setup, so that I can restart the whole thing from afar if need be.

For now, however, I’m putting superfluous ISO storage repositories on each server I set up (I can’t share the “SR” between the servers, because one is running xcp-ng 8.0 and the other is 8.2).

Log into the hypervisor through ssh.

ssh root@<hypervisor hostname or IP>

Decide where to put the ISO storage repository. I think /var/opt/xen/ is a default location, but it really doesn’t matter. Stick it in /root/, jam it in /opt/diskimages/, I don’t care. Though, /tmp/ wouldn’t be a good choice, and /dev/ or /proc/ would probably kill your system. Note the trailing /, which will be important later on when this variable is reused.

mkdir -pv $sr_path

Pick a name for your ISO repository. This is what will show up in XCP-ng Center as the name of the storage repository, so pick something at least semi-memorable.

sr_name="installation disk images"

This is where the magic happens: tell the hypervisor about the purpose of the new folder, and specify that it’s specifically for the purpose of holding ISOs that get inserted in virtual DVD drives.

xe sr-create name-label="$sr_name" type=iso device-config:location="$sr_path" \
    device-config:legacy_mode=true content-type=iso

Now you can open up XCP-ng Center and see the new ISO repository. It’ll be empty, though, so the next trick is adding the disks. I like using the debian net installer as a default OS, so the Debian 10 netinstall ISO will be my example here.

For some reason, wget doesn’t like running inside the hypervisor in my experience; maybe it’ll be different for you. If you feel like experimenting, try this:

cd $sr_path

However, I’ve usually found it effective to download it to a different (linux) system, and then upload it with scp to the hypervisor. (again, all this nonsense will be superceded when I set up that management box with an NFS ISO repository…) Do the following on the not-hypervisor linux system.

scp debian-10.6.0-amd64-netinst.iso root@"$hypervisor_ip_address":"$sr_path" 

Note that I’m continuing to use the same bash variables defined earlier for the repository path. At this point, you can go back into XCP-ng Center and refresh the contents of your storage repository and see the new disk image. If you do, it’s ready for use setting up a new VM. If you don’t…it worked for me.