Basic cells support

Adds support for running a region and child cell within a single
devstack environment.

README.md has been updated with some info on getting started.

Rebased/updated from initial work by Andrew Laski <andrew.laski@rackspace.com>.

Change-Id: Ic181da2180ccaa51df7efc9d66f7ccb820aac19b
diff --git a/README.md b/README.md
index 6570a14..1987db8 100644
--- a/README.md
+++ b/README.md
@@ -153,3 +153,23 @@
     MYSQL_HOST=$SERVICE_HOST
     RABBIT_HOST=$SERVICE_HOST
     Q_HOST=$SERVICE_HOST
+
+# Cells
+
+Cells is a new scaling option with a full spec at http://wiki.openstack.org/blueprint-nova-compute-cells.
+
+To setup a cells environment add the following to your `localrc`:
+
+    enable_service n-cell
+    enable_service n-api-meta
+    MULTI_HOST=True
+
+    # The following have not been tested with cells, they may or may not work.
+    disable_service n-obj
+    disable_service cinder
+    disable_service c-sch
+    disable_service c-api
+    disable_service c-vol
+    disable_service n-xvnc
+
+Be aware that there are some features currently missing in cells, one notable one being security groups.
diff --git a/lib/nova b/lib/nova
index 6fa1db4..6fc0c79 100644
--- a/lib/nova
+++ b/lib/nova
@@ -37,6 +37,9 @@
 
 NOVA_CONF_DIR=/etc/nova
 NOVA_CONF=$NOVA_CONF_DIR/nova.conf
+NOVA_CELLS_CONF=$NOVA_CONF_DIR/nova-cells.conf
+NOVA_CELLS_DB=${NOVA_CELLS_DB:-nova_cell}
+
 NOVA_API_PASTE_INI=${NOVA_API_PASTE_INI:-$NOVA_CONF_DIR/api-paste.ini}
 
 # Public facing bits
@@ -125,10 +128,6 @@
 # Functions
 # ---------
 
-function add_nova_opt {
-    echo "$1" >>$NOVA_CONF
-}
-
 # Helper to clean iptables rules
 function clean_iptables() {
     # Delete rules
@@ -415,7 +414,6 @@
 
     # (Re)create ``nova.conf``
     rm -f $NOVA_CONF
-    add_nova_opt "[DEFAULT]"
     iniset $NOVA_CONF DEFAULT verbose "True"
     iniset $NOVA_CONF DEFAULT debug "True"
     iniset $NOVA_CONF DEFAULT auth_strategy "keystone"
@@ -539,6 +537,32 @@
     iniset $NOVA_CONF DEFAULT glance_api_servers "$GLANCE_HOSTPORT"
 }
 
+function init_nova_cells() {
+    if is_service_enabled n-cell; then
+        cp $NOVA_CONF $NOVA_CELLS_CONF
+        iniset $NOVA_CELLS_CONF DEFAULT sql_connection `database_connection_url $NOVA_CELLS_DB`
+        iniset $NOVA_CELLS_CONF DEFAULT rabbit_virtual_host child_cell
+        iniset $NOVA_CELLS_CONF DEFAULT dhcpbridge_flagfile $NOVA_CELLS_CONF
+        iniset $NOVA_CELLS_CONF cells enable True
+        iniset $NOVA_CELLS_CONF cells name child
+
+        iniset $NOVA_CONF DEFAULT scheduler_topic cells
+        iniset $NOVA_CONF DEFAULT compute_api_class nova.compute.cells_api.ComputeCellsAPI
+        iniset $NOVA_CONF cells enable True
+        iniset $NOVA_CONF cells name region
+
+        if is_service_enabled n-api-meta; then
+            NOVA_ENABLED_APIS=$(echo $NOVA_ENABLED_APIS | sed "s/,metadata//")
+            iniset $NOVA_CONF DEFAULT enabled_apis $NOVA_ENABLED_APIS
+            iniset $NOVA_CELLS_CONF DEFAULT enabled_apis metadata
+        fi
+
+        $NOVA_BIN_DIR/nova-manage --config-file $NOVA_CELLS_CONF db sync
+        $NOVA_BIN_DIR/nova-manage --config-file $NOVA_CELLS_CONF cell create --name=region --cell_type=parent --username=guest --hostname=$RABBIT_HOST --port=5672 --password=$RABBIT_PASSWORD --virtual_host=/ --woffset=0 --wscale=1
+        $NOVA_BIN_DIR/nova-manage cell create --name=child --cell_type=child --username=guest --hostname=$RABBIT_HOST --port=5672 --password=$RABBIT_PASSWORD --virtual_host=child_cell --woffset=0 --wscale=1
+    fi
+}
+
 # create_nova_cache_dir() - Part of the init_nova() process
 function create_nova_cache_dir() {
     # Create cache dir
@@ -578,6 +602,10 @@
         # Migrate nova database
         $NOVA_BIN_DIR/nova-manage db sync
 
+        if is_service_enabled n-cell; then
+            recreate_database $NOVA_CELLS_DB latin1
+        fi
+
         # (Re)create nova baremetal database
         if is_baremetal; then
             recreate_database nova_bm latin1
@@ -648,14 +676,26 @@
 
 # start_nova() - Start running processes, including screen
 function start_nova() {
-    # The group **$LIBVIRT_GROUP** is added to the current user in this script.
-    # Use 'sg' to execute nova-compute as a member of the **$LIBVIRT_GROUP** group.
+    NOVA_CONF_BOTTOM=$NOVA_CONF
+
     # ``screen_it`` checks ``is_service_enabled``, it is not needed here
     screen_it n-cond "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-conductor"
-    screen_it n-cpu "cd $NOVA_DIR && sg $LIBVIRT_GROUP $NOVA_BIN_DIR/nova-compute"
+
+    if is_service_enabled n-cell; then
+        NOVA_CONF_BOTTOM=$NOVA_CELLS_CONF
+        screen_it n-cond "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-conductor --config-file $NOVA_CELLS_CONF"
+        screen_it n-cell "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-cells --config-file $NOVA_CONF"
+        screen_it n-cell "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-cells --config-file $NOVA_CELLS_CONF"
+    fi
+
+    # The group **$LIBVIRT_GROUP** is added to the current user in this script.
+    # Use 'sg' to execute nova-compute as a member of the **$LIBVIRT_GROUP** group.
+    screen_it n-cpu "cd $NOVA_DIR && sg $LIBVIRT_GROUP \"$NOVA_BIN_DIR/nova-compute --config-file $NOVA_CONF_BOTTOM\""
     screen_it n-crt "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-cert"
-    screen_it n-net "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-network"
-    screen_it n-sch "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-scheduler"
+    screen_it n-net "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-network --config-file $NOVA_CONF_BOTTOM"
+    screen_it n-sch "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-scheduler --config-file $NOVA_CONF_BOTTOM"
+    screen_it n-api-meta "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-api-metadata --config-file $NOVA_CONF_BOTTOM"
+
     screen_it n-novnc "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-novncproxy --config-file $NOVA_CONF --web $NOVNC_DIR"
     screen_it n-xvnc "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-xvpvncproxy --config-file $NOVA_CONF"
     screen_it n-spice "cd $NOVA_DIR && $NOVA_BIN_DIR/nova-spicehtml5proxy --config-file $NOVA_CONF --web $SPICE_DIR"
@@ -670,7 +710,9 @@
 # stop_nova() - Stop running processes (non-screen)
 function stop_nova() {
     # Kill the nova screen windows
-    for serv in n-api n-cpu n-crt n-net n-sch n-novnc n-xvnc n-cauth n-cond n-spice; do
+    # Some services are listed here twice since more than one instance
+    # of a service may be running in certain configs.
+    for serv in n-api n-cpu n-crt n-net n-sch n-novnc n-xvnc n-cauth n-spice n-cond n-cond n-cell n-cell n-api-meta; do
         screen -S $SCREEN_NAME -p $serv -X kill
     done
 }
diff --git a/lib/rpc_backend b/lib/rpc_backend
index 27d3ba3..6b334a9 100644
--- a/lib/rpc_backend
+++ b/lib/rpc_backend
@@ -138,6 +138,13 @@
         fi
         # change the rabbit password since the default is "guest"
         sudo rabbitmqctl change_password guest $RABBIT_PASSWORD
+        if is_service_enabled n-cell; then
+            # Add partitioned access for the child cell
+            if [ -z `sudo rabbitmqctl list_vhosts | grep child_cell` ]; then
+                sudo rabbitmqctl add_vhost child_cell
+                sudo rabbitmqctl set_permissions -p child_cell guest ".*" ".*" ".*"
+            fi
+        fi
     elif is_service_enabled qpid; then
         echo_summary "Starting qpid"
         restart_service qpidd
diff --git a/stack.sh b/stack.sh
index c0a314d..37abd6d 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1034,6 +1034,8 @@
         LIBVIRT_FIREWALL_DRIVER=${LIBVIRT_FIREWALL_DRIVER:-"nova.virt.libvirt.firewall.IptablesFirewallDriver"}
         iniset $NOVA_CONF DEFAULT firewall_driver "$LIBVIRT_FIREWALL_DRIVER"
     fi
+
+    init_nova_cells
 fi
 
 # Extra things to prepare nova for baremetal, before nova starts
@@ -1094,14 +1096,19 @@
     create_quantum_initial_network
     setup_quantum_debug
 elif is_service_enabled $DATABASE_BACKENDS && is_service_enabled n-net; then
+    NM_CONF=${NOVA_CONF}
+    if is_service_enabled n-cell; then
+        NM_CONF=${NOVA_CELLS_CONF}
+    fi
+
     # Create a small network
-    $NOVA_BIN_DIR/nova-manage network create "$PRIVATE_NETWORK_NAME" $FIXED_RANGE 1 $FIXED_NETWORK_SIZE $NETWORK_CREATE_ARGS
+    $NOVA_BIN_DIR/nova-manage --config-file $NM_CONF network create "$PRIVATE_NETWORK_NAME" $FIXED_RANGE 1 $FIXED_NETWORK_SIZE $NETWORK_CREATE_ARGS
 
     # Create some floating ips
-    $NOVA_BIN_DIR/nova-manage floating create $FLOATING_RANGE --pool=$PUBLIC_NETWORK_NAME
+    $NOVA_BIN_DIR/nova-manage --config-file $NM_CONF floating create $FLOATING_RANGE --pool=$PUBLIC_NETWORK_NAME
 
     # Create a second pool
-    $NOVA_BIN_DIR/nova-manage floating create --ip_range=$TEST_FLOATING_RANGE --pool=$TEST_FLOATING_POOL
+    $NOVA_BIN_DIR/nova-manage --config-file $NM_CONF floating create --ip_range=$TEST_FLOATING_RANGE --pool=$TEST_FLOATING_POOL
 fi
 
 if is_service_enabled quantum; then