Vagrantfileを作って、vagrant up をしたら、エラーになって起動できなかった。

vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: You assigned a static IP ending in ".1" to this machine.
==> default: This is very often used by the router and can cause the
==> default: network to not work properly. If the network doesn't work
==> default: properly, try changing this IP.
==> default: Importing base box 'bento/centos-7.2'...
==> default: Matching MAC address for NAT networking...
==> default: You assigned a static IP ending in ".1" to this machine.
==> default: This is very often used by the router and can cause the
==> default: network to not work properly. If the network doesn't work
==> default: properly, try changing this IP.
==> default: Checking if box 'bento/centos-7.2' is up to date...
==> default: Setting the name of the VM: DRBD84-CentOS7-Vagrant_default_1481156483725_36997
==> default: Fixed port collision for 22 => 2222. Now on port 2200.
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
    default: Adapter 2: hostonly
    default: Adapter 3: hostonly
    default: Adapter 4: bridged
==> default: Forwarding ports...
    default: 22 (guest) => 2200 (host) (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2200
    default: SSH username: vagrant
    default: SSH auth method: private key
    default: Warning: Remote connection disconnect. Retrying...
    default: Warning: Remote connection disconnect. Retrying...
    default: Warning: Remote connection disconnect. Retrying...
Timed out while waiting for the machine to boot. This means that
Vagrant was unable to communicate with the guest machine within
the configured ("config.vm.boot_timeout" value) time period.

If you look above, you should be able to see the error(s) that
Vagrant had when attempting to connect to the machine. These errors
are usually good hints as to what may be wrong.

If you're using a custom box, make sure that networking is properly
working and you're able to connect to the machine. It is a common
problem that networking isn't setup properly in these boxes.
Verify that authentication configurations are also setup properly,
as well.

If the box appears to be booting properly, you may want to increase
the timeout ("config.vm.boot_timeout") value.

どうやら、ネットワークの設定部分でおかしいようだったので、コメントアウトしてみたら、ビンゴ！

#config.vm.network "private_network", type: "dhcp"
 config.vm.network "private_network", ip: "192.168.56.105"
#config.vm.network "private_network", ip: "10.0.30.1", virtualbox__intnet: "eth1"
#config.vm.network "private_network", ip: "10.0.31.1", virtualbox__intnet: "eth2"

このエラー内容をみると、どうも起動するときに、ネットワークの接続確認をしているようにみえる。
設定には注意がいりそう。