Snapped Open

Snap is used for additional administration. Use the snap --help command for more information on administering snaps (Figure 2). However, before you install snaps to complete the AP, assign a new host name (in this example, pi3) and set the time zone correctly,

$ sudo hostnamectl set-hostname pi3
$ sudo timedatectl set-timezone America/New_York

Figure 2: Familiarize yourself with Ubuntu's new Snap packaging system by calling the help switch.

then relaunch the system. After logging in again via SSH, install the wifi-ap snap and then call the script for interactive configuration,

$ snap install wifi-ap
$ sudo wifi-ap.setup-wizard

which requires some manual intervention.

In the Wizard, first assign an SSID and, in this case, a password. If you want to set up a public hotspot, respond that you do not want to specify a password. When asked for the IP address, enter 192.168.1.1 or a custom network address. After further questions, which you may answer in the negative (n), if appropriate, enable the AP in the last response. The setup is now complete (Figure 3).

Figure 3: The automated procedure saves you from manual configuration at various points.

Integrating the USB Disk

Installing the Nextcloud file server should be trouble-free with Ubuntu Core. To prepare your system for use with Nextcloud, connect a USB memory stick or hard drive to the AP. You can recognize the correct device by its size in the lsblk -l output. Alternatively, call

sudo dmesg | tail

after connecting, and glean the information from its output.

Once you know the mass storage identifier, create a USB mount unit called media-usbdisk.mount in the /etc/systemd/system/ directory (Figure 4). Add the contents of Listing 1 to this file by adjusting the name of the device file accordingly.

Figure 4: Only the Vi editor is available for creating a systemd USB mount unit.

The Unit section integrates the external hard drive, but first you have to make it known to the system, so you can use the mass storage:

$ sudo systemctl daemon-reload
$ sudo systemctl enable media-usbdisk.mount
$ sudo systemctl start media-usbdisk.mount

To continue, install Nextcloud and allow the snap to interact with the hard drive:

$ snap install nextcloud
$ snap connect nextcloud:removable-media

Now you should give Nextcloud a few minutes while the configuration runs in the background. After a coffee break, create a self-signed certificate,

$ sudo nextcloud.enable-https self-signed

which is sufficient for domestic use. Alternatively, integrate an existing certificate, or create one from Let's Encrypt (Figure 5) with the command:

$ sudo nextcloud.enable-https lets-encrypt

Figure 5: Using a certificate from Let's Encrypt requires some additional work.

However, you must first prepare the Apache web server – a subject in itself.

Everything is now ready to connect to the AP and to launch Nextcloud. Begin by looking on any computer or other WiFi-enabled device at the list of networks offered and connect to the AP (Figure 6).

Figure 6: On the laptop, the established ubucore connection is available in the NetworkManager.

Next, call https://<Nextcloud IP address> (i.e., the address you assigned to Nextcloud) in your browser. The final step for storing data on the external drive is to select the External Storage app in the Nextcloud GUI and then point /media/usbdisk/ in the admin back end (Figure 7).

Figure 7: The External Storage app lets you store what you have connected to the Rasp Pi AP on the external drive.

Conclusions

Rarely has it been so easy to set up a wireless AP in a private cloud. The development of the AP itself takes about half an hour; including the Nextcloud setup takes about an hour. The procedure described here is ideal for devices that are inconspicuous in everyday life and provide their service out of sight.

The AP remains secure because of the encrypted SSH connection to the account and the Ubuntu Snappy Core automatic updates – with the option of returning to the old state in the event of problems.

The integration of Nextcloud on an external disk connected to a Rasp Pi only represents one of the many options for this AP. If necessary, you can easily set up a hot spot, guest access, or a center for home automation on the Raspberry Pi AP.