diff --git a/site/operational-guide/concepts.md b/site/operational-guide/concepts.md
index 85df5eff..c2584120 100644
--- a/site/operational-guide/concepts.md
+++ b/site/operational-guide/concepts.md
@@ -49,16 +49,12 @@ When the router is launched on a host, it derives its peer name in order of pref
 
 * From the command line, where the user is responsible for uniqueness and
   stability
-* From the concatenated result of any of the following:
-    * The unique machine ID, which is generated either by [systemd](https://www.freedesktop.org/software/systemd/man/machine-id.html)
-      or [D-Bus](https://dbus.freedesktop.org/doc/dbus-uuidgen.1.html) and is
-      practically stable across restarts unless a user re-generates it.
-    * The BIOS product UUID, which is generally stable across
-      restarts and unique across different physical hardware and certain
-      cloned VMs
-    * The hypervisor UUID, which is generally stable across restarts
-      and unique across VMs which do not provide access to a BIOS product
-      UUID
+* From the BIOS product UUID, which is generally stable across
+  restarts and unique across different physical hardware and certain
+  cloned VMs
+* From the hypervisor UUID, which is generally stable across restarts
+  and unique across VMs which do not provide access to a BIOS product
+  UUID
 * From a random value, practically unique across different physical
   hardware and cloned VMs but not stable across restarts
 
diff --git a/weave b/weave
index d1fd3a00..dc48ab8f 100755
--- a/weave
+++ b/weave
@@ -143,22 +143,12 @@ launch_router_options() {
     [ "$1" = "launch" -o "$1" = "launch-router" ] && echo -v /:/host -e HOST_ROOT=/host
 }
 
-exec_options() {
-    case "$1" in
-        # Required by create_bridge which might need machine-id
-        launch|launch-router|create-bridge|attach-router|run|start|attach|restart|expose|hide)
-            echo -v /etc:/host/etc -v /var/lib/dbus:/host/var/lib/dbus -e HOST_ROOT=/host
-            ;;
-    esac
-}
-
 exec_remote() {
     docker $DOCKER_CLIENT_ARGS run --rm \
         $(docker_run_options) \
         --pid=host \
         $(cni_volume_options "$@") \
         $(launch_router_options "$@") \
-        $(exec_options "$@") \
         -e DOCKERHUB_USER="$DOCKERHUB_USER" \
         -e WEAVE_VERSION \
         -e WEAVE_DEBUG \
@@ -461,11 +451,12 @@ mac_from_hex() {
     read a b c d e f && printf "%02x:$b:$c:$d:$e:$f" $((0x$a & ~1 | 2))
 }
 
-mac_from_uid() {
+mac_from_file() {
+    UUID=$(cat $1 2>/dev/null) || return 1
     # We salt the input just as a precaution to avoid clashes with
     # other applications who might have had the bright idea of
     # generating MACs in the same way.
-    echo "9oBJ0Jmip-$1" | sha256sum | sed 's/\(..\)/\1 /g' | cut -c1-17 | mac_from_hex
+    echo "9oBJ0Jmip-$UUID" | sha256sum | sed 's/\(..\)/\1 /g' | cut -c1-17 | mac_from_hex
 }
 
 # Generate a random MAC value
@@ -473,11 +464,6 @@ random_mac() {
     od -txC -An -N6 /dev/urandom | mac_from_hex
 }
 
-machineid() {
-    cat "$HOST_ROOT/etc/machine-id" 2>/dev/null && return 0 || true
-    cat "$HOST_ROOT/var/lib/dbus/machine-id" 2>/dev/null && return 0 || true
-}
-
 ######################################################################
 # weave and docker specific helpers
 ######################################################################
@@ -710,16 +696,16 @@ init_bridge() {
 
     ip link add name $BRIDGE type bridge
 
-    # Derive the bridge MAC from concatenated machine-id (either systemd or
-    # dbus), the system (aka bios) UUID and the hypervisor UUID. If we cannot
-    # determine all of them we just generate a random MAC.
-    # Elsewhere we in turn derive the peer name from the bridge MAC, which we
-    # want to be stable across reboots but otherwise unique.
-
-    uid="$(machineid)"
-    uid="$uid#$(cat /sys/class/dmi/id/product_uuid 2>/dev/null || echo '')"
-    uid="$uid#$(cat /sys/hypervisor/uuid 2>/dev/null || echo '')"
-    [ "$uid" != "##" ] && MAC=$(mac_from_uid "$uid") || MAC=$(random_mac)
+    # Derive the bridge MAC from the system (aka bios) UUID, or,
+    # failing that, the hypervisor UUID. Elsewhere we in turn derive
+    # the peer name from that, which we want to be stable across
+    # reboots but otherwise unique. The system/hypervisor UUID fits
+    # that bill, unlike, say, /etc/machine-id, which is often
+    # identical on VMs created from cloned filesystems. If we cannot
+    # determine the system/hypervisor UUID we just generate a random MAC.
+    MAC=$(mac_from_file /sys/class/dmi/id/product_uuid) || \
+        MAC=$(mac_from_file /sys/hypervisor/uuid) || \
+        MAC=$(random_mac)
 
     ip link set dev $BRIDGE address $MAC