roster:
dns-dns-01.inf.us-west-2.aws.acme.com:
  host: 10.10.32.10
  sudo: True
  grains:
    is_ssh: 1


command:
salt-ssh -i dns-dns-01.inf.us-west-2.aws.acme.com test.ping

Output:
[ERROR   ] An un-handled exception was caught by salt's global exception handler:
TypeError: object of type 'NoneType' has no len()
Traceback (most recent call last):
  File "/usr/bin/salt-ssh", line 10, in <module>
    salt_ssh()
  File "/usr/lib/python2.7/site-packages/salt/scripts.py", line 425, in salt_ssh
    client.run()
  File "/usr/lib/python2.7/site-packages/salt/cli/ssh.py", line 23, in run
    ssh = salt.client.ssh.SSH(self.config)
  File "/usr/lib/python2.7/site-packages/salt/client/ssh/__init__.py", line 235, in __init__
    self.tgt_type)
  File "/usr/lib/python2.7/site-packages/salt/roster/__init__.py", line 105, in targets
    targets.update(self.rosters[f_str](tgt, tgt_type))
  File "/usr/lib/python2.7/site-packages/salt/roster/flat.py", line 50, in targets
    return rmatcher.targets()
  File "/usr/lib/python2.7/site-packages/salt/roster/flat.py", line 68, in targets
    return getattr(self, 'ret_{0}_minions'.format(self.tgt_type))()
  File "/usr/lib/python2.7/site-packages/salt/roster/flat.py", line 78, in ret_glob_minions
    if fnmatch.fnmatch(minion, self.tgt):
  File "/usr/lib64/python2.7/fnmatch.py", line 43, in fnmatch
    return fnmatchcase(name, pat)
  File "/usr/lib64/python2.7/fnmatch.py", line 79, in fnmatchcase
    res = translate(pat)
  File "/usr/lib64/python2.7/fnmatch.py", line 91, in translate
    i, n = 0, len(pat)
TypeError: object of type 'NoneType' has no len()
Traceback (most recent call last):
  File "/usr/bin/salt-ssh", line 10, in <module>
    salt_ssh()
  File "/usr/lib/python2.7/site-packages/salt/scripts.py", line 425, in salt_ssh
    client.run()
  File "/usr/lib/python2.7/site-packages/salt/cli/ssh.py", line 23, in run
    ssh = salt.client.ssh.SSH(self.config)
  File "/usr/lib/python2.7/site-packages/salt/client/ssh/__init__.py", line 235, in __init__
    self.tgt_type)
  File "/usr/lib/python2.7/site-packages/salt/roster/__init__.py", line 105, in targets
    targets.update(self.rosters[f_str](tgt, tgt_type))
  File "/usr/lib/python2.7/site-packages/salt/roster/flat.py", line 50, in targets
    return rmatcher.targets()
  File "/usr/lib/python2.7/site-packages/salt/roster/flat.py", line 68, in targets
    return getattr(self, 'ret_{0}_minions'.format(self.tgt_type))()
  File "/usr/lib/python2.7/site-packages/salt/roster/flat.py", line 78, in ret_glob_minions
    if fnmatch.fnmatch(minion, self.tgt):
  File "/usr/lib64/python2.7/fnmatch.py", line 43, in fnmatch
    return fnmatchcase(name, pat)
  File "/usr/lib64/python2.7/fnmatch.py", line 79, in fnmatchcase
    res = translate(pat)
  File "/usr/lib64/python2.7/fnmatch.py", line 91, in translate
    i, n = 0, len(pat)
TypeError: object of type 'NoneType' has no len()