VirtualBox networking

# VirtualBox: Host<->Guest Networking

To simplify performing/testing automation on VirtualBox, we need to assign static IP Addresses to our VMs.

Create a Host Only network.

Virtual Box -> Preferences -> Network -> Host-only Networks

For this example, we will use `vboxnet0`

Use the following settings:
```
IPv4 Address: 192.168.59.1
IPv4 Network Mask: 255.255.255.0
IPv6 Address: <blank>
IPv6 Network Mask Length: 0
```

By default a new VM in VirtualBox will use a NAT adapter. This allows it to connect to the Internet, but prevents us from SSH-ing into the server so we need to attach a second network adapter to our VM.

```
VM -> Settings -> Network -> Adapter 2
```

We use a host-only adapter instead of a bridge adapter, because a bridge adapter adds the VM to your actual network. If it communicates with your DHCP server, there is a good chance that the IP address changes every time you restart.

Make sure:
- the checkbox for `Enable Network Adapter` is on.
- we are attached to the `Host-only Adapter` named `vboxnet0`

When we run our VM and check the interfaces it will only show 2: the loopback interface and the NAT interface.
```
$ ifconfig

enp0s3    Link encap:Ethernet  HWaddr 08:00:27:6a:99:77
          inet addr:10.0.2.15  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe6a:9977/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:27 errors:0 dropped:0 overruns:0 frame:0
          TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4349 (4.3 KB)  TX bytes:4903 (4.9 KB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:160 errors:0 dropped:0 overruns:0 frame:0
          TX packets:160 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:11840 (11.8 KB)  TX bytes:11840 (11.8 KB)
```

We need to manually add our Host-only Adapter by editing `/etc/network/interfaces`.

When we open it, this will be the file content:
```
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet dhcp
```

At the end of the file we need to add a new interface.
```
# Host-only network
auto enp0s8
iface enp0s8 inet static
dns-nameservers 8.8.8.8 8.8.4.4
address 192.168.59.2
network 192.168.59.1
netmask 255.255.255.0
broadcast 192.168.59.255
```

After saving, we need to pick up the new configuration.

There are two ways to do this.

Activating the interface:
```
sudo ifup enp0s8
```

Or restarting the whole networking service:
```
sudo service networking restart
```

## OpenSSH setup
Since are trying to emulate the servers in our local machines, we need to be able to SSH into the VMs using our public keys.

Make sure openssh-server is installed.
```
sudo apt-get install openssh-server
```

Copy your public key to `~/.ssh/authorized_keys`
```
mkdir ~/.ssh`
vi ~/.ssh/authorized_keys
```