[CRITICAL] Failed to load grains defined in grain file extra.config in function <function config at 0x7fa99f919488>, error:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/salt/loader.py", line 727, in grains
    ret = fun()
  File "/usr/lib/python2.7/dist-packages/salt/grains/extra.py", line 44, in config
    with salt.utils.fopen(gfn, 'rb') as fp_:
  File "/usr/lib/python2.7/dist-packages/salt/utils/__init__.py", line 1242, in fopen
    fhandle = open(*args, **kwargs)
IOError: [Errno 13] Permission denied: '/etc/salt/grains'