Improvement the Tricircle work with nova cell2

1. What is the problem
Create instance can't find image and the document need to update

2. What is the solution to the problem
Change the plugin.sh to fix the error of image not found
update the document for work with nova cell v2

3. What the features need to be implemented to the Tricircle
None

Signed-off-by: chenyaguang <chenyaguang@szzt.com.cn>
Co-Authored-By：tangzhuo <ztang@hnu.edu.cn>

Change-Id: I3deec4a2d8315d92d383157f20f101dfef11ddcd

devstack/plugin.sh

@@ -244,8 +244,12 @@ function start_central_nova_server {
     nova_legacy_url=$(openstack endpoint list --service compute_legacy --interface public --region $local_region -c URL -f value)
     get_or_create_endpoint "compute_legacy" "$central_region" "$nova_legacy_url"
 
-    image_endpoint_id=$(openstack endpoint list --service image --interface public --region $local_region -c ID -f value)
-    openstack endpoint set --region $central_region $image_endpoint_id
+    central_image_endpoint_id=$(openstack endpoint list --service image --interface public --region $central_region -c ID -f value)
+    if [[ -z "$central_image_endpoint_id" ]]; then
+        glance_url=$(openstack endpoint list --service image --interface public --region $local_region -c URL -f value)
+        get_or_create_endpoint "image" "$central_region" "$glance_url"
+    fi
+
     place_endpoint_id=$(openstack endpoint list --service placement --interface public --region $local_region -c ID -f value)
     openstack endpoint set --region $central_region $place_endpoint_id
 

doc/source/install/installation-cell.rst

@@ -28,6 +28,9 @@ Setup
     systemctl stop devstack@n-sch.service
     systemctl stop devstack@n-super-cond.service
     systemctl stop devstack@n-api.service
+
+  if the service of devstack@n-api-meta.service exists, stop it::
+
     systemctl stop devstack@n-api-meta.service
 
 .. note:: Actually for cell v2, only one Nova API is required. We enable n-api
@@ -65,7 +68,7 @@ Setup
 
   then you can see the new cell and host are added in the database::
 
-    mysql -u$user -p$password -Dnova -e 'select cell_id, host from host_mappings'
+    mysql -u$user -p$password -Dnova_api -e 'select cell_id, host from host_mappings'
 
     +---------+-----------+
     | cell_id | host      |
@@ -74,7 +77,7 @@ Setup
     |       3 | zhiyuan-2 |
     +---------+-----------+
 
-    mysql -u$user -p$password -Dnova -e 'select id, name from cell_mappings'
+    mysql -u$user -p$password -Dnova_api -e 'select id, name from cell_mappings'
 
     +----+-------+
     | id | name  |
@@ -84,13 +87,9 @@ Setup
     |  3 | cell2 |
     +----+-------+
 
-- 5 In node1, run the following commands to use nova_cell1 database in nova configure files::
-
-    sed -i "s/nova_cell0/nova_cell1/g" `grep nova_cell0 -rl /etc/nova`
+- 5 In node1, run the following commands::
 
     systemctl restart devstack@n-sch.service
-    systemctl restart devstack@n-super-cond.service
-    systemctl restart devstack@n-cpu.service
 
 - 6 In node1, check if compute services in both hosts are registered::