Issue: CentOS 7 network not in VirtualBox

Issue: Fresh installed CentOS 7 network interface not working.

[root@localhost slean]# ip addr
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
   link/ether 08:00:27:c8:da:c2 brd ff:ff:ff:ff:ff:ff
[root@localhost slean]#

As you can see the interface doesn't have IP address.

To fix this issue, first edit the network interface.  nmtui is a network manager tool user interface.
[root@localhost slean]# nmtui

Select the interface and click "Edit".

Enable the DHCP by setting the Automatically connect and make sure the IPv4 CONFIGURATION to <Automatic>.

Click <OK> and <Quit>.

[root@localhost slean]# system restart network

[root@localhost slean]# ip addr

Source: krizna.com