diff --git a/planetstack/observer/steps/garbage_collector.py b/planetstack/observer/steps/garbage_collector.py
index f03577c..4b6dfaf 100644
--- a/planetstack/observer/steps/garbage_collector.py
+++ b/planetstack/observer/steps/garbage_collector.py
@@ -8,4 +8,198 @@
 
 	def call(self):
 		pass
-        
+
+    def run(self):
+        try:
+            logger.info('gc start')
+            #self.sync_roles()
+            self.gc_tenants()
+            self.gc_users()
+            self.gc_user_tenant_roles()
+            self.gc_slivers()
+            self.gc_sliver_ips()
+            self.gc_external_routes()
+        except:
+            traceback.print_exc() 
+
+    def gc_roles(self):
+        """
+         all role that don't already exist in keystone. Remove keystone roles that
+        don't exist in planetstack
+        """
+        # sync all roles that don't already in keystone  
+        keystone_roles = self.driver.shell.keystone.roles.findall()
+        keystone_role_names = [kr.name for kr in keystone_roles]
+        pending_roles = Role.objects.all()
+        pending_role_names = [r.role_type for r in pending_roles] 
+        # don't delete roles for now 
+        """ 
+        # delete keystone roles that don't exist in planetstack
+        for keystone_role in keystone_roles:
+            if keystone_role.name == 'admin':
+                continue
+            if keystone_role.name not in pending_role_names:
+                try:
+                    self.manager.driver.delete_role({id: keystone_role.id})
+                except:
+                    traceback.print_exc()
+        """
+
+    def gc_tenants(self):
+        """
+        Remove sites and slices that no don't exist in openstack db if they 
+        have an enacted time (enacted != None).
+        """ 
+        # get all sites that where enacted != null. We can assume these sites
+        # have previously been synced and need to be checed for deletion.
+        sites = Site.objects.filter(enacted__isnull=False)
+        site_dict = {}
+        for site in sites:
+            site_dict[site.login_base] = site
+
+        # get all slices that where enacted != null. We can assume these slices
+        # have previously been synced and need to be checed for deletion.
+        slices = Slice.objects.filter(enacted__isnull=False)
+        slice_dict = {}
+        for slice in slices:
+            slice_dict[slice.name] = slice
+
+        # delete keystone tenants that don't have a site record
+        tenants = self.driver.shell.keystone.tenants.findall()
+        system_tenants = ['admin','service']
+        for tenant in tenants:
+            if tenant.name in system_tenants: 
+                continue
+            if tenant.name not in site_dict and tenant.name not in slice_dict:
+                try:
+                    self.driver.delete_tenant(tenant.id)
+                    logger.info("deleted tenant: %s" % (tenant))
+                except:
+                    logger.log_exc("delete tenant failed: %s" % tenant)
+
+
+    def gc_users(self):
+        """
+        Remove users that no don't exist in openstack db if they have an 
+        enacted time (enacted != None).
+        """ 
+        # get all users that where enacted != null. We can assume these users
+        # have previously been synced and need to be checed for deletion.
+        users = User.objects.filter(enacted__isnull=False)
+        user_dict = {}
+        for user in users:
+            user_dict[user.kuser_id] = user
+
+        # delete keystone users that don't have a user record
+        system_users = ['admin', 'nova', 'quantum', 'glance', 'cinder', 'swift', 'service']
+        users = self.driver.shell.keystone.users.findall()
+        for user in users:
+            if user.name in system_users:
+                continue
+            if user.id not in user_dict:
+                try:
+                    #self.manager.driver.delete_user(user.id)
+                    logger.info("deleted user: %s" % user)
+                except:
+                    logger.log_exc("delete user failed: %s" % user)
+                    
+
+    def gc_user_tenant_roles(self):
+        """
+        Remove roles that don't exist in openstack db if they have 
+        an enacted time (enacted != None).
+        """
+        # get all site privileges and slice memberships that have been enacted 
+        user_tenant_roles = defaultdict(list)
+        for site_priv in SitePrivilege.objects.filter(enacted__isnull=False):
+            user_tenant_roles[(site_priv.user.kuser_id, site_priv.site.tenant_id)].append(site_priv.role.role)
+        for slice_memb in SliceMembership.objects.filter(enacted__isnull=False):
+            user_tenant_roles[(slice_memb.user.kuser_id, slice_memb.slice.tenant_id)].append(slice_memb.role.role)  
+ 
+        # Some user tenant role aren't stored in planetstack but they must be preserved. 
+        # Role that fall in this category are
+        # 1. Never remove a user's role that their home site
+        # 2. Never remove a user's role at a slice they've created.
+        # Keep track of all roles that must be preserved.     
+        users = User.objects.all()
+        preserved_roles = {}
+        for user in users:
+            tenant_ids = [s['tenant_id'] for s in user.slices.values()]
+            tenant_ids.append(user.site.tenant_id) 
+            preserved_roles[user.kuser_id] = tenant_ids
+
+ 
+        # begin removing user tenant roles from keystone. This is stored in the 
+        # Metadata table.
+        for metadata in self.driver.shell.keystone_db.get_metadata():
+            # skip admin roles
+            if metadata.user_id == self.manager.driver.admin_user.id:
+                continue
+            # skip preserved tenant ids
+            if metadata.user_id in preserved_roles and \
+               metadata.tenant_id in preserved_roles[metadata.user_id]: 
+                continue           
+            # get roles for user at this tenant
+            user_tenant_role_ids = user_tenant_roles.get((metadata.user_id, metadata.tenant_id), [])
+
+            if user_tenant_role_ids:
+                # The user has roles at the tenant. Check if roles need to 
+                # be updated.
+                user_keystone_role_ids = metadata.data.get('roles', [])
+                for role_id in user_keystone_role_ids:
+                    if role_id not in user_tenant_role_ids: 
+                        user_keystone_role_ids.pop(user_keystone_role_ids.index(role_id))
+            else:
+                # The user has no roles at this tenant. 
+                metadata.data['roles'] = [] 
+            #session.add(metadata)
+            logger.info("pruning metadata for %s at %s" % (metadata.user_id, metadata.tenant_id))
+ 
+    def gc_slivers(self):
+        """
+        Remove slivers that no don't exist in openstack db if they have 
+        an enacted time (enacted != None).
+        """
+        # get all slivers where enacted != null. We can assume these users
+        # have previously been synced and need to be checed for deletion.
+        slivers = Sliver.objects.filter(enacted__isnull=False)
+        sliver_dict = {}
+        for sliver in slivers:
+            sliver_dict[sliver.instance_id] = sliver
+
+        # delete sliver that don't have a sliver record
+        ctx = self.driver.shell.nova_db.ctx 
+        instances = self.driver.shell.nova_db.instance_get_all(ctx)
+        for instance in instances:
+            if instance.uuid not in sliver_dict:
+                try:
+                    # lookup tenant and update context  
+                    tenant = self.driver.shell.keystone.tenants.find(id=instance.project_id)
+                    driver = self.driver.client_driver(tenant=tenant.name) 
+                    driver.destroy_instance(instance.uuid)
+                    logger.info("destroyed sliver: %s" % (instance))
+                except:
+                    logger.log_exc("destroy sliver failed: %s" % instance) 
+                
+
+    def gc_sliver_ips(self):
+        """
+        Update ips that have changed.
+        """
+        # fill in null ip addresses
+        slivers = Sliver.objects.filter(ip=None)
+        for sliver in slivers:
+            # update connection
+            self.manager.init_admin(tenant=sliver.slice.name)
+            servers = self.manager.driver.shell.nova.servers.findall(id=sliver.instance_id)
+            if not servers:
+                continue
+            server = servers[0]
+            ips = server.addresses.get(sliver.slice.name, [])
+            if ips and sliver.ip != ips[0]['addr']:
+                sliver.ip = ips[0]['addr']
+                sliver.save()
+                logger.info("updated sliver ip: %s %s" % (sliver, ips[0]))
+
+    def gc_external_routes(self):
+        pass