createrepo has a  --unique-md-filenames switch that causes the repodata files (e.g. primary.xml.gz) to be named uniquely by having their checksum prepended to the filename.  This is necessary in environments where there is a proxy between the end user and the repodata.  By not uniquely naming the files, the proxy will return stale, cached data.  Please include the following patch.

diff --git a/src/pulp/server/util.py b/src/pulp/server/util.py
index eee5a0e..6dc2d65 100644
--- a/src/pulp/server/util.py
+++ b/src/pulp/server/util.py
@@ -451,15 +451,15 @@ def create_symlinks(source_path, link_path):
         
 def _create_repo(dir, groups=None, checksum_type="sha256"):
     try:
-        cmd = "createrepo --database --checksum %s -g %s --update %s " % (checksum_type, groups, dir)
+        cmd = "createrepo --unique-md-filenames --database --checksum %s -g %s --update %s " % (checksum_type, groups, dir)
     except UnicodeDecodeError:
         checksum_type = decode_unicode(checksum_type)
         if groups:
             groups = decode_unicode(groups)
         dir = decode_unicode(dir)
-        cmd = "createrepo --database --checksum %s -g %s --update %s " % (checksum_type, groups, dir)
+        cmd = "createrepo --unique-md-filenames --database --checksum %s -g %s --update %s " % (checksum_type, groups, dir)
     if not groups:
-        cmd = "createrepo --database --checksum %s --update %s " % (checksum_type, dir)
+        cmd = "createrepo --unique-md-filenames --database --checksum %s --update %s " % (checksum_type, dir)
         repodata_file = os.path.join(dir, "repodata", "repomd.xml")
         repodata_file = encode_unicode(repodata_file)
         if os.path.isfile(repodata_file):
@@ -476,7 +476,7 @@ def _create_repo(dir, groups=None, checksum_type="sha256"):
                 renamed_comps_file = os.path.join(dir, renamed_filetype_path)
                 os.rename(filetype_path, renamed_comps_file)
                 if renamed_comps_file and os.path.isfile(renamed_comps_file):
-                    cmd = "createrepo --database --checksum %s -g %s --update %s " % \
+                    cmd = "createrepo --unique-md-filenames --database --checksum %s -g %s --update %s " % \
                         (checksum_type, renamed_comps_file, dir)
 
     # shlex now can handle unicode strings as well