Add a flag to set the default file mode of logs.

nova/flags.py

@@ -343,7 +343,7 @@ DEFINE_string('lock_path', os.path.join(os.path.dirname(__file__), '../'),
               'Directory for lock files')
 DEFINE_string('logdir', None, 'output to a per-service log file in named '
                               'directory')
-
+DEFINE_integer('logfile_mode', 0644, 'Default file mode of the logs.')
 DEFINE_string('sqlite_db', 'nova.sqlite', 'file name for sqlite')
 DEFINE_string('sql_connection',
               'sqlite:///$state_path/$sqlite_db',

nova/log.py

@@ -257,6 +257,7 @@ class NovaRootLogger(NovaLogger):
                 self.filelog = WatchedFileHandler(logpath)
                 self.addHandler(self.filelog)
                 self.logpath = logpath
+                os.chmod(self.logpath, FLAGS.logfile_mode)
         else:
             self.removeHandler(self.filelog)
             self.addHandler(self.streamlog)