Salt PAM not loading

salt-pam.log

[root@salt-master ~]# salt  "salt*" test.ping -l all -a pam
[DEBUG   ] Reading configuration from /etc/salt/master
[DEBUG   ] Missing configuration file: /root/.salt
[TRACE   ] loading log_handlers in ['/var/cache/salt/master/extmods/log_handlers', '/opt/local/lib/python2.7/site-packages/salt/log/handlers']
[TRACE   ] Skipping /var/cache/salt/master/extmods/log_handlers, it is not a directory
[DEBUG   ] Loaded logstash_mod as virtual logstash
[TRACE   ] Added logstash.DatagramLogstashHandler to log_handlers
[TRACE   ] Added logstash.LogstashFormatter to log_handlers
[TRACE   ] Added logstash.NewStyleClassMixIn to log_handlers
[TRACE   ] Added logstash.ZMQLogstashHander to log_handlers
[TRACE   ] Added logstash.setup_handlers to log_handlers
[INFO    ] Processing `log_handlers.logstash`
[DEBUG   ] Adding the 'logstash' provided logging handler: <salt.loaded.int.log_handlers.logstash_mod.DatagramLogstashHandler object at 0x177b350>
[DEBUG   ] Configuration file path: /etc/salt/master
[DEBUG   ] Reading configuration from /etc/salt/master
[DEBUG   ] Missing configuration file: /root/.salt
[DEBUG   ] LocalClientEvent PUB socket URI: ipc:///var/run/salt/master/master_event_pub.ipc
[DEBUG   ] LocalClientEvent PULL socket URI: ipc:///var/run/salt/master/master_event_pull.ipc
[TRACE   ] loading auth in ['/var/cache/salt/master/extmods/auth', '/opt/local/lib/python2.7/site-packages/salt/auth']
[TRACE   ] Skipping /var/cache/salt/master/extmods/auth, it is not a directory
[TRACE   ] Added auto.auth to auth
[TRACE   ] Added keystone.auth to auth
[TRACE   ] Added keystone.get_auth_url to auth
[TRACE   ] Added ldap.Environment to auth
[TRACE   ] Added ldap.auth to auth
The specified external authentication system "pam" is not available