Install ansible via pip
$ sudo pip install ansible
On CentOS 6.5, OpenSSH update was necessary. (This helped to avoid fatal: [default] => using -c ssh on certain older ssh versions may not support ControlPersist, set ANSIBLE_SSH_ARGS="" (or ssh_args in [ssh_connection] section of the config file) before running again
.)
$ sudo yum update openssh
...
Updated:
openssh.x86_64 0:5.3p1-104.el6_6.1
$ vagrant up