diff --git a/docs/schema-upgrade-1.17-1.18.sql b/docs/schema-upgrade-1.17-1.18.sql
index 2c3e716f..3163e630 100644
--- a/docs/schema-upgrade-1.17-1.18.sql
+++ b/docs/schema-upgrade-1.17-1.18.sql
@@ -26,10 +26,11 @@ CREATE INDEX sessions_expired ON sessions(expired);
 -- table for content generator build reservations
 CREATE TABLE build_reservations (
 	build_id INTEGER NOT NULL REFERENCES build(id),
-	user_id INTEGER NOT NULL REFERENCES users(id),
+	cg_id INTEGER NOT NULL REFERENCES content_generator(id),
 	token VARCHAR(64),
+        created TIMESTAMP NOT NULL,
 	PRIMARY KEY (build_id)
 ) WITHOUT OIDS;
-
+CREATE INDEX build_reservations_created ON build_reservations(created);
 
 COMMIT;
diff --git a/docs/schema.sql b/docs/schema.sql
index 8b69fe68..d499d3ae 100644
--- a/docs/schema.sql
+++ b/docs/schema.sql
@@ -299,13 +299,6 @@ CREATE TABLE build_types (
 ) WITHOUT OIDS;
 
 
-CREATE TABLE build_reservations (
-	build_id INTEGER NOT NULL REFERENCES build(id),
-	user_id INTEGER NOT NULL REFERENCES users(id),
-	token VARCHAR(64),
-	PRIMARY KEY (build_id)
-) WITHOUT OIDS;
-
 -- Note: some of these CREATEs may seem a little out of order. This is done to keep
 -- the references sane.
 
@@ -514,6 +507,14 @@ CREATE TABLE cg_users (
 	UNIQUE (cg_id, user_id, active)
 ) WITHOUT OIDS;
 
+CREATE TABLE build_reservations (
+	build_id INTEGER NOT NULL REFERENCES build(id),
+	cg_id INTEGER NOT NULL REFERENCES content_generator(id),
+	token VARCHAR(64),
+        created TIMESTAMP NOT NULL,
+	PRIMARY KEY (build_id)
+) WITHOUT OIDS;
+CREATE INDEX build_reservations_created ON build_reservations(created);
 
 -- here we track the buildroots on the machines
 CREATE TABLE buildroot (
diff --git a/hub/kojihub.py b/hub/kojihub.py
index 4f61491d..4f60b2a1 100644
--- a/hub/kojihub.py
+++ b/hub/kojihub.py
@@ -5566,10 +5566,12 @@ def cg_init_build(cg, data):
     build_id = new_build(data, strict=True)
     # store token
     token = generate_token()
+    cg_id = lookup_name('content_generator', cg, strict=True)['id']
     insert = InsertProcessor(table='build_reservations')
-    insert.set(build_id=build_id)
-    insert.set(user_id=context.session.user_id)
-    insert.set(token=token)
+    insert.set(build_id=build_id,
+               cg_id=cg_id,
+               token=token)
+    insert.rawset(created='NOW()')
     insert.execute()
 
     return {'build_id': build_id, 'token': token}
@@ -5720,7 +5722,7 @@ class CG_Importer(object):
     def get_reserve_token(self, build_id):
         query = QueryProcessor(
             tables=['build_reservations'],
-            columns=['build_id', 'user_id', 'token'],
+            columns=['build_id', 'cg_id', 'token'],
             clauses=['build_id = %(build_id)d'],
             values=locals(),
         )
@@ -5730,11 +5732,14 @@ class CG_Importer(object):
     def prep_build(self, token=None):
         metadata = self.metadata
         if metadata['build'].get('build_id'):
+            if len(self.cgs) != 1:
+                raise koji.GenericError("Reserved builds can handle only single content generator.")
+            cg_id = list(self.cgs)[0]
             build_id = metadata['build']['build_id']
             buildinfo = get_build(build_id, strict=True)
             build_token = self.get_reserve_token(build_id)
             if not build_token or build_token['token'] != token or \
-               build_token['user_id'] != context.session.user_id or \
+               build_token['cg_id'] != cg_id or \
                buildinfo['state'] != koji.BUILD_STATES['BUILDING']:
                 raise koji.GenericError('Build ID %s is not reserved by this CG' % build_id)
             if buildinfo['name'] != metadata['build']['name'] or \
@@ -5792,10 +5797,13 @@ class CG_Importer(object):
             binfo = dslice(self.buildinfo, ('name', 'version', 'release'))
             buildinfo = get_build(binfo, strict=True)
             build_token = self.get_reserve_token(buildinfo['build_id'])
+            if len(self.cgs) != 1:
+                raise koji.GenericError("Reserved builds can handle only single content generator.")
+            cg_id = list(self.cgs)[0]
             if buildinfo.get('task_id') or \
                buildinfo['state'] != koji.BUILD_STATES['BUILDING'] or \
                not build_token or \
-               build_token['user_id'] != context.session.user_id or \
+               build_token['cg_id'] != cg_id or \
                build_token['token'] != token:
                 raise koji.GenericError("Build is not reserved")
             buildinfo['extra'] = self.buildinfo['extra']