Merge branch 'master' of github.com:cloudbuilders/devstack
diff --git a/stack.sh b/stack.sh
index 6dbc885..a0ff193 100755
--- a/stack.sh
+++ b/stack.sh
@@ -322,9 +322,7 @@
     # device - used to manage qcow images)
     sudo modprobe nbd || true
     sudo modprobe kvm || true
-    # user needs to be member of libvirtd group for nova-compute to use libvirt
-    ## FIXME: this doesn't affect the current shell so you end up with a failed
-    ## launch of nova-compute
+    # User needs to be member of libvirtd group for nova-compute to use libvirt.
     sudo usermod -a -G libvirtd `whoami`
     # if kvm wasn't running before we need to restart libvirt to enable it
     sudo /etc/init.d/libvirt-bin restart
@@ -394,9 +392,9 @@
 # so send the start command by forcing text into the window.
 # Only run the services specified in ``ENABLED_SERVICES``
 
-NL=`echo -ne '\015'`
-
+# our screen helper to launch a service in a hidden named screen
 function screen_it {
+    NL=`echo -ne '\015'`
     if [[ "$ENABLED_SERVICES" =~ "$1" ]]; then
         screen -S nova -X screen -t $1
         screen -S nova -p $1 -X stuff "$2$NL"
@@ -407,7 +405,13 @@
 screen_it g-reg "cd $GLANCE_DIR; bin/glance-registry --config-file=etc/glance-registry.conf"
 screen_it key "$KEYSTONE_DIR/bin/keystone --config-file $KEYSTONE_CONF"
 screen_it n-api "$NOVA_DIR/bin/nova-api"
-screen_it n-cpu "$NOVA_DIR/bin/nova-compute"
+# Launching nova-compute should be as simple as running ``nova-compute`` but 
+# have to do a little more than that in our script.  Since we add the group 
+# ``libvirtd`` to our user in this script, when nova-compute is run it is
+# within the context of our original shell (so our groups won't be updated). 
+# We can send the command nova-compute to the ``newgrp`` command to execute
+# in a specific context.
+screen_it n-cpu "echo $NOVA_DIR/bin/nova-compute | newgrp libvirtd"
 screen_it n-net "$NOVA_DIR/bin/nova-network"
 screen_it n-sch "$NOVA_DIR/bin/nova-scheduler"
 # nova-vncproxy binds a privileged port, and so needs sudo