diff --git a/devstack-vm-gate.sh b/devstack-vm-gate.sh
index 19be8d4c..a071601b 100755
--- a/devstack-vm-gate.sh
+++ b/devstack-vm-gate.sh
@@ -61,8 +61,31 @@ function setup_ssh {
 }
 
 function setup_multinode_connectivity {
+    local mode=${1:-"devstack"}
+    # Multinode setup variables:
+    #
+    # ``localrc`` - location to write localrc content on the primary
+    # node. In grenade mode we write to the grenade template that is
+    # copied into old and new.
+    #
+    # ``old_or_new`` - should the subnodes be computed on the old side
+    # or new side. For grenade where we don't upgrade them, calculate
+    # on the old side.
+    local localrc=$BASE/new/devstack/localrc
+    local old_or_new="new"
+    if [[ "$mode" == "grenade" ]]; then
+        localrc=$BASE/new/grenade/devstack.localrc
+        old_or_new="old"
+    fi
+    # set explicit paths on all conf files we're writing so that
+    # current working directory doesn't introduce subtle bugs.
+    local devstack_dir=$BASE/$old_or_new/devstack
+    local sub_localrc=$devstack_dir/sub_localrc
+    local localconf=$devstack_dir/local.conf
+
     set -x  # for now enabling debug and do not turn it off
-    setup_localrc "new" "sub_localrc" "sub"
+    setup_localrc $old_or_new "$sub_localrc" "sub"
+
     PRIMARY_NODE=`cat /etc/nodepool/primary_node_private`
     SUB_NODES=`cat /etc/nodepool/sub_nodes_private`
     if [[ "$DEVSTACK_GATE_NEUTRON" -ne '1' ]]; then
@@ -72,12 +95,12 @@ function setup_multinode_connectivity {
                        $SUB_NODES
         ovs_gre_bridge "br_flat" $PRIMARY_NODE "False" 128 \
                        $SUB_NODES
-        cat <<EOF >>"$BASE/new/devstack/sub_localrc"
+        cat <<EOF >>"$sub_localrc"
 FLAT_INTERFACE=br_flat
 PUBLIC_INTERFACE=br_pub
 MULTI_HOST=True
 EOF
-        cat <<EOF >>"$BASE/new/devstack/localrc"
+        cat <<EOF >>"$localrc"
 FLAT_INTERFACE=br_flat
 PUBLIC_INTERFACE=br_pub
 MULTI_HOST=True
@@ -104,17 +127,18 @@ EOF
     # set up ssh_known_host files based on hostname
     for HOSTNAME in `cat /tmp/tmp_hosts | cut -d' ' -f2`; do
         ssh-keyscan $HOSTNAME >> /tmp/tmp_ssh_known_hosts
-        done
+    done
+
     $ANSIBLE all --sudo -f 5 -i "$WORKSPACE/inventory" -m copy \
              -a "src=/tmp/tmp_ssh_known_hosts dest=/etc/ssh/ssh_known_hosts mode=0444"
 
     for NODE in $SUB_NODES; do
         remote_copy_file /tmp/tmp_hosts $NODE:/tmp/tmp_hosts
         remote_command $NODE "cat /tmp/tmp_hosts | sudo tee --append /etc/hosts > /dev/null"
-        cp sub_localrc /tmp/tmp_sub_localrc
+        cp $sub_localrc /tmp/tmp_sub_localrc
         echo "HOST_IP=$NODE" >> /tmp/tmp_sub_localrc
-        remote_copy_file /tmp/tmp_sub_localrc $NODE:$BASE/new/devstack/localrc
-        remote_copy_file local.conf $NODE:$BASE/new/devstack/local.conf
+        remote_copy_file /tmp/tmp_sub_localrc $NODE:$devstack_dir/localrc
+        remote_copy_file $localconf $NODE:$localconf
     done
 }
 
@@ -542,14 +566,35 @@ EOF
         echo "$GRENADE_PLUGINRC" >>$BASE/new/grenade/pluginrc
     fi
 
+    if [[ "$DEVSTACK_GATE_TOPOLOGY" == "multinode" ]]; then
+        echo -e "[[post-config|\$NOVA_CONF]]\n[libvirt]\ncpu_mode=custom\ncpu_model=gate64" >> local.conf
+        # this pins everything to the rpc version of the stable side
+        echo -e "[upgrade_levels]\ncompute=$(basename $GRENADE_OLD_BRANCH)" >> local.conf
+        # get this in our base config
+        cp local.conf $BASE/old/devstack
+
+        setup_multinode_connectivity "grenade"
+
+        # build the post-stack.sh config, this will be run as stack user so no sudo required
+        cat > $BASE/new/grenade/post-stack.sh <<EOF
+#!/bin/bash
+
+set -x
+
+$ANSIBLE subnodes -f 5 -i "$WORKSPACE/inventory" -m shell \
+        -a "cd '$BASE/old/devstack' && stdbuf -oL -eL ./stack.sh"
+EOF
+        sudo chmod a+x $BASE/new/grenade/post-stack.sh
+    fi
+
     # Make the workspace owned by the stack user
     # It is not clear if the ansible file module can do this for us
     $ANSIBLE all --sudo -f 5 -i "$WORKSPACE/inventory" -m shell \
         -a "chown -R stack:stack '$BASE'"
 
-    cd $BASE/new/grenade
     echo "Running grenade ..."
     echo "This takes a good 30 minutes or more"
+    cd $BASE/new/grenade
     sudo -H -u stack stdbuf -oL -eL ./grenade.sh
     cd $BASE/new/devstack