libvirt: Drop support for Xen

This hasn't been validated upstream and there doesn't appear to be
anyone using it. It's time to drop support for this. This is mostly test
and documentation damage, though there is some other cleanup going on,
like the removal of the essentially noop 'pick_disk_driver_name' helper.

Change-Id: I73305e82da5d8da548961b801a8e75fb0e8c4cf1
Signed-off-by: Stephen Finucane <[email protected]>

Author: stephenfin

doc/source/admin/arch.rst

@@ -68,7 +68,6 @@ availability zones. Compute supports the following hypervisors:
 - `VMware vSphere
   <https://www.vmware.com/support/vsphere-hypervisor.html>`__
 
-- `Xen (using libvirt) <https://www.xenproject.org>`__
 
 - `zVM <https://www.ibm.com/it-infrastructure/z/zvm>`__
 

doc/source/admin/configuration/hypervisor-vmware.rst

@@ -811,7 +811,7 @@ Tag VMware images
 In a mixed hypervisor environment, OpenStack Compute uses the
 ``hypervisor_type`` tag to match images to the correct hypervisor type.  For
 VMware images, set the hypervisor type to ``vmware``.  Other valid hypervisor
-types include: ``hyperv``, ``ironic``, ``lxc``, ``qemu``, and ``xen``.
+types include: ``hyperv``, ``ironic``, ``lxc``, and ``qemu``.
 Note that ``qemu`` is used for both QEMU and KVM hypervisor types.
 
 .. code-block:: console

doc/source/admin/configuration/hypervisor-xen-libvirt.rst

@@ -8,7 +8,6 @@ Hypervisors
    hypervisor-basics
    hypervisor-kvm
    hypervisor-qemu
-   hypervisor-xen-libvirt
    hypervisor-lxc
    hypervisor-vmware
    hypervisor-hyper-v
@@ -39,10 +38,6 @@ The following hypervisors are supported:
 * `VMware vSphere`_ 5.1.0 and newer - Runs VMware-based Linux and Windows
   images through a connection with a vCenter server.
 
-* `Xen (using libvirt)`_ - Xen Project Hypervisor using libvirt as
-  management interface into ``nova-compute`` to run Linux, Windows, FreeBSD and
-  NetBSD virtual machines.
-
 * `Hyper-V`_ - Server virtualization with Microsoft Hyper-V, use to run
   Windows, Linux, and FreeBSD virtual machines.  Runs ``nova-compute`` natively
   on the Windows virtualization platform.
@@ -90,7 +85,6 @@ virt drivers:
 .. _LXC: https://linuxcontainers.org
 .. _QEMU: https://wiki.qemu.org/Manual
 .. _VMware vSphere: https://www.vmware.com/support/vsphere-hypervisor.html
-.. _Xen (using libvirt): https://www.xenproject.org
 .. _Hyper-V: https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/hyper-v-technology-overview
 .. _Virtuozzo: https://www.virtuozzo.com/products/vz7.html
 .. _PowerVM: https://www.ibm.com/us-en/marketplace/ibm-powervm