diff --git a/planetstack/openstack/driver.py b/planetstack/openstack/driver.py
index 0e5fbf0..ce0b883 100644
--- a/planetstack/openstack/driver.py
+++ b/planetstack/openstack/driver.py
@@ -358,18 +358,18 @@
 
         return (subnet_id, subnet)
 
-    def spawn_instance(self, name, key_name=None, hostname=None, image_id=None, security_group=None, pubkeys=[], nics=None):
+    def spawn_instance(self, name, key_name=None, hostname=None, image_id=None, security_group=None, pubkeys=[], nics=None, metadata=None):
         flavor_name = self.config.nova_default_flavor
         flavor = self.shell.nova.flavors.find(name=flavor_name)
         #if not image:
         #    image = self.config.nova_default_imave
         if not security_group:
-            security_group = self.config.nova_default_security_group 
+            security_group = self.config.nova_default_security_group
 
         files = {}
-        if pubkeys:    
+        if pubkeys:
             files['/root/.ssh/authorized_keys'] = "\n".join(pubkeys)
-       
+
         hints = {}
         availability_zone = None
         if hostname:
@@ -383,7 +383,8 @@
                                             files=files,
                                             scheduler_hints=hints,
                                             availability_zone=availability_zone,
-                                            nics=nics)
+                                            nics=nics,
+                                            meta=metadata)
         return server
 
     def destroy_instance(self, id):
diff --git a/planetstack/openstack/manager.py b/planetstack/openstack/manager.py
index 2fb4ff8..9ede33f 100644
--- a/planetstack/openstack/manager.py
+++ b/planetstack/openstack/manager.py
@@ -315,9 +315,22 @@
 
     @require_enabled
     def save_sliver(self, sliver):
+        metadata_update = {}
+        if ("numberCores" in sliver.changed_fields):
+            metadata_update["cpu_cores"] = str(sliver.numberCores)
+
+        for tag in sliver.slice.tags.all():
+            if tag.name.startswith("sysctl-"):
+                metadata_update[tag.name] = tag.value
+
         if not sliver.instance_id:
             nics = self.get_requested_networks(sliver.slice)
-            file("/tmp/scott-manager","a").write("slice: %s\nreq: %s\n" % (str(sliver.slice.name), str(nics)))
+            for nic in nics:
+                # If a network hasn't been instantiated yet, then we'll fail
+                # during slice creation. Defer saving the sliver for now.
+                if not nic.get("net-id", None):
+                    sliver.save()   # in case it hasn't been saved yet
+                    return
             slice_memberships = SliceMembership.objects.filter(slice=sliver.slice)
             pubkeys = [sm.user.public_key for sm in slice_memberships if sm.user.public_key]
             pubkeys.append(sliver.creator.public_key)
@@ -326,12 +339,13 @@
                                    image_id = sliver.image.image_id,
                                    hostname = sliver.node.name,
                                    pubkeys = pubkeys,
-                                   nics = nics )
+                                   nics = nics,
+                                   metadata = metadata_update )
             sliver.instance_id = instance.id
             sliver.instance_name = getattr(instance, 'OS-EXT-SRV-ATTR:instance_name')
-
-        if sliver.instance_id and ("numberCores" in sliver.changed_fields):
-            self.driver.update_instance_metadata(sliver.instance_id, {"cpu_cores": str(sliver.numberCores)})
+        else:
+            if metadata_update:
+                self.driver.update_instance_metadata(sliver.instance_id, metadata_update)
 
         sliver.save()
         sliver.enacted = datetime.now()