@@ -655,6 +655,8 @@ case "$VIRT_DRIVER" in

         ;;

 esac

+# By default, devstack will use Ubuntu Cloud Archive.

+ENABLE_UBUNTU_CLOUD_ARCHIVE=$(trueorfalse True ENABLE_UBUNTU_CLOUD_ARCHIVE)

 # Images

 # ------

@@ -72,7 +72,10 @@ fi

 # We've found that Libvirt on Xenial is flaky and crashes enough to be

 # a regular top e-r bug. Opt into Ubuntu Cloud Archive if on Xenial to

 # get newer Libvirt.

-if [[ "$DISTRO" = "xenial" ]]; then

+# Make it possible to switch this based on an environment variable as

+# libvirt 2.5.0 doesn't handle nested virtualization quite well and this

+# is required for the trove development environment.

+if [[ "${ENABLE_UBUNTU_CLOUD_ARCHIVE}" == "True" && "$DISTRO" = "xenial" ]]; then

     # This pulls in apt-add-repository

     install_package "software-properties-common"

     # Use UCA for newer libvirt. Should give us libvirt 2.5.0.