config.ssh.username = 'root'
config.ssh.password = 'vagrant'
config.ssh.insert_key = 'true'

$ vagrant reload
==> dev: Attempting graceful shutdown of VM...
    dev: Guest communication could not be established! This is usually because
    dev: SSH is not running, the authentication information was changed,
    dev: or some other networking issue. Vagrant will force halt, if
    dev: capable.
==> dev: Forcing shutdown of VM...
==> dev: Clearing any previously set forwarded ports...
==> dev: Clearing any previously set network interfaces...
==> dev: Preparing network interfaces based on configuration...
    dev: Adapter 1: nat
    dev: Adapter 2: bridged
==> dev: Forwarding ports...
    dev: 22 (guest) => 2222 (host) (adapter 1)
==> dev: Booting VM...
==> dev: Waiting for machine to boot. This may take a few minutes...
    dev: SSH address: 127.0.0.1:2222
    dev: SSH username: root
    dev: SSH auth method: password
    dev: Warning: Authentication failure. Retrying...
    dev: Warning: Authentication failure. Retrying...
    dev: Warning: Authentication failure. Retrying...
    dev: Warning: Authentication failure. Retrying...
    dev: Warning: Authentication failure. Retrying...
    dev: Warning: Authentication failure. Retrying...
    dev: Warning: Authentication failure. Retrying...