diff --git a/docs/cookbook/container/default.sha256.do b/docs/cookbook/container/default.sha256.do
index bb6e042..67f1e83 100644
--- a/docs/cookbook/container/default.sha256.do
+++ b/docs/cookbook/container/default.sha256.do
@@ -5,7 +5,7 @@ import hashlib, os, subprocess, sys
 subprocess.check_call([
     'redo-ifchange',
     sys.argv[2],
-])
+], close_fds=False)
 
 h = hashlib.sha256()
 f = open(sys.argv[2])
diff --git a/docs/cookbook/container/dockjson.py b/docs/cookbook/container/dockjson.py
index cb01640..11a4bec 100755
--- a/docs/cookbook/container/dockjson.py
+++ b/docs/cookbook/container/dockjson.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 """Generate a docker 1.0-style manifest for a docker image."""
-import json, os, subprocess, sys, time
+import json, os, sys, time
 
 j = json.load(open('template.json'))
 layerid = open(sys.argv[1] + '.list.sha256').read().strip()