In this branch we are forwarding incoming requests to child zones when the requested resource is not found in the current zone.

For example: If 'nova pause 123' is issued against Zone 1, but instance 123 does not live in Zone 1, the call will be forwarded to all child zones hoping someone can deal with it.

NOTE: This currently only works with OpenStack API requests and routing checks are only being done against Compute/instance_id checks.
Specifically:
* servers.get/pause/unpause/diagnostics/suspend/resume/rescue/unrescue/delete
* servers.create is pending for distributed scheduler
* servers.get_all will get added early in Diablo.

What I've been doing for testing:
1. Set up a Nova deployment in a VM (Zone0)
2. Clone the VM and set --zone_name=zone1 (and change all the IP addresses to the new address in nova.conf, glance.conf and novarc)
3. Set --enable_zone_routing=true on all zones
4. use the --connection_type=fake driver for compute to keep things easy
5. Add Zone1 as a child of Zone0 (nova zone-add)

(make sure the instance id's are different in each zone)

Example of calls being sent to child zones:
http://paste.openstack.org/show/964/

2 files changed, 28 insertions, 11 deletions

diff --git a/nova/api/openstack/servers.py b/nova/api/openstack/servers.py
index 1b4f28f59..0dad46268 100644
--- a/nova/api/openstack/servers.py
+++ b/nova/api/openstack/servers.py
@@ -37,6 +37,7 @@ from nova.auth import manager as auth_manager
 from nova.compute import instance_types
 from nova.compute import power_state
 import nova.api.openstack
+from nova.scheduler import api as scheduler_api
 
 
 LOG = logging.getLogger('server')
@@ -87,15 +88,18 @@ class Controller(wsgi.Controller):
                 for inst in limited_list]
         return dict(servers=servers)
 
+    @scheduler_api.redirect_handler
     def show(self, req, id):
         """ Returns server details by server id """
         try:
-            instance = self.compute_api.get(req.environ['nova.context'], id)
+            instance = self.compute_api.routing_get(
+                req.environ['nova.context'], id)
             builder = self._get_view_builder(req)
             return builder.build(instance, is_detail=True)
         except exception.NotFound:
             return faults.Fault(exc.HTTPNotFound())
 
+    @scheduler_api.redirect_handler
     def delete(self, req, id):
         """ Destroys a server """
         try:
@@ -226,6 +230,7 @@ class Controller(wsgi.Controller):
         # if the original error is okay, just reraise it
         raise error
 
+    @scheduler_api.redirect_handler
     def update(self, req, id):
         """ Updates the server name or password """
         if len(req.body) == 0:
@@ -251,6 +256,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPNotFound())
         return exc.HTTPNoContent()
 
+    @scheduler_api.redirect_handler
     def action(self, req, id):
         """Multi-purpose method used to reboot, rebuild, or
         resize a server"""
@@ -316,6 +322,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def lock(self, req, id):
         """
         lock the instance with id
@@ -331,6 +338,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def unlock(self, req, id):
         """
         unlock the instance with id
@@ -346,6 +354,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def get_lock(self, req, id):
         """
         return the boolean state of (instance with id)'s lock
@@ -360,6 +369,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def reset_network(self, req, id):
         """
         Reset networking on an instance (admin only).
@@ -374,6 +384,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def inject_network_info(self, req, id):
         """
         Inject network info for an instance (admin only).
@@ -388,6 +399,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def pause(self, req, id):
         """ Permit Admins to Pause the server. """
         ctxt = req.environ['nova.context']
@@ -399,6 +411,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def unpause(self, req, id):
         """ Permit Admins to Unpause the server. """
         ctxt = req.environ['nova.context']
@@ -410,6 +423,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def suspend(self, req, id):
         """permit admins to suspend the server"""
         context = req.environ['nova.context']
@@ -421,6 +435,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def resume(self, req, id):
         """permit admins to resume the server from suspend"""
         context = req.environ['nova.context']
@@ -432,6 +447,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def rescue(self, req, id):
         """Permit users to rescue the server."""
         context = req.environ["nova.context"]
@@ -443,6 +459,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def unrescue(self, req, id):
         """Permit users to unrescue the server."""
         context = req.environ["nova.context"]
@@ -454,6 +471,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPUnprocessableEntity())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def get_ajax_console(self, req, id):
         """ Returns a url to an instance's ajaxterm console. """
         try:
@@ -463,6 +481,7 @@ class Controller(wsgi.Controller):
             return faults.Fault(exc.HTTPNotFound())
         return exc.HTTPAccepted()
 
+    @scheduler_api.redirect_handler
     def diagnostics(self, req, id):
         """Permit Admins to retrieve server diagnostics."""
         ctxt = req.environ["nova.context"]
diff --git a/nova/api/openstack/zones.py b/nova/api/openstack/zones.py
index d4a59993b..846cb48a1 100644
--- a/nova/api/openstack/zones.py
+++ b/nova/api/openstack/zones.py
@@ -17,6 +17,7 @@ import common
 
 from nova import db
 from nova import flags
+from nova import log as logging
 from nova import wsgi
 from nova.scheduler import api
 
@@ -38,7 +39,8 @@ def _exclude_keys(item, keys):
 
 
 def _scrub_zone(zone):
-    return _filter_keys(zone, ('id', 'api_url'))
+    return _exclude_keys(zone, ('username', 'password', 'created_at',
+                    'deleted', 'deleted_at', 'updated_at'))
 
 
 class Controller(wsgi.Controller):
@@ -53,12 +55,8 @@ class Controller(wsgi.Controller):
         # Ask the ZoneManager in the Scheduler for most recent data,
         # or fall-back to the database ...
         items = api.get_zone_list(req.environ['nova.context'])
-        if not items:
-            items = db.zone_get_all(req.environ['nova.context'])
-
         items = common.limited(items, req)
-        items = [_exclude_keys(item, ['username', 'password'])
-                      for item in items]
+        items = [_scrub_zone(item) for item in items]
         return dict(zones=items)
 
     def detail(self, req):
@@ -81,23 +79,23 @@ class Controller(wsgi.Controller):
     def show(self, req, id):
         """Return data about the given zone id"""
         zone_id = int(id)
-        zone = db.zone_get(req.environ['nova.context'], zone_id)
+        zone = api.zone_get(req.environ['nova.context'], zone_id)
         return dict(zone=_scrub_zone(zone))
 
     def delete(self, req, id):
         zone_id = int(id)
-        db.zone_delete(req.environ['nova.context'], zone_id)
+        api.zone_delete(req.environ['nova.context'], zone_id)
         return {}
 
     def create(self, req):
         context = req.environ['nova.context']
         env = self._deserialize(req.body, req.get_content_type())
-        zone = db.zone_create(context, env["zone"])
+        zone = api.zone_create(context, env["zone"])
         return dict(zone=_scrub_zone(zone))
 
     def update(self, req, id):
         context = req.environ['nova.context']
         env = self._deserialize(req.body, req.get_content_type())
         zone_id = int(id)
-        zone = db.zone_update(context, zone_id, env["zone"])
+        zone = api.zone_update(context, zone_id, env["zone"])
         return dict(zone=_scrub_zone(zone))