ivanpollak.com

This blog post contains information on my journey to install Alpine Linux on my homelabbing server. This "server" actually is just an old laptop, that I do not actively use anymore. Since it is powerful enough to run as a server and quite efficient while doing so, I've decided to repurpose it as my server.

Setting up the boot drive

The first step of all new OS installations is to obtain an image for the given operating system. For alpine, they have a downloads page with various options to choose from. Due to the fact, that I will use a laptop, I've decided to go with the extended option. This should include "AMD and Intel microcode updates."

After flashing the device with dd:

sudo dd if=alpine-extended-3.23.4-x86_64.iso of=/dev/disk4

I've proceeded to the installing section of alpine's User Handbook. There I found out, that the setup-alpine script, which is used for easily installing alpine linux on a system, does not setup WiFi connections by itself.

Since I will use WiFi as the main way to communicate with my server, this ment that I would need to configure networking manually.

Issues with WiFI

Sadly, setting up WiFi wasn't as easy as I thought. Because alpine is a pretty minimalistic distribution, the driver for my network device (Intel(R) Wi-Fi 6E AX211 160MHz) was missing. This was probably due to the fact that apk info (alpine's way to list all installed packages) did not show any linux-firmware-intel.

So after searching an ethernet cable and doing the same for a free ethernet port, I was finally able to run setup-alpine -q to start using alpine. This allowed me to ping an external website for the first time. After running the -q (quick) version of the setup-alpine command, and testing the connection, the real installation began.

Installing alpine

Alpine linux has a pretty handy script, called setup-alpine this will guide the user through the installation process, asking him various questions on how the system should be installed. This includes; setting the keyboard layout, changing the hostname, setup the primary (wired) interface, use dhcp or not and various other things. All of those are described in the user handbook.

Most values, I've left to their defaults. If I did not understand the options, entering the ? instead of any option, outputted a very detailed and easy to understand description of what option does what. What I think is notable, is that you even can select between different implementations (for example you can choose between openssh and other ssh servers, if you want). Also, the help menu will describe when to use what. For example; if the user is not sure, how to use the disk, the help menu describes what option is better for what purpose. sys is best for development boxes, desktops and virtual servers, crypt is the same as sys but with encription, etc.

Because only I have physical access to this system, it was save for me, to choose the sys option.

After the installation was finished, I was prompted to reboot the system. I've done what the computer told me and look at that, alpine is now installed.

Setting up WiFi

After the installation worked as it should, it was now time to make it possible to use the computer without an ethernet connection. I've apk add-ed the previously mentioned linux-firmware-intel and finally ip addr showed my wlan0.

Actually, I think, that the setup-alpine script already installed the linux-firmware-intel package alongside with some other common linux-firmware-* packages.

Alpine supports both wpa_supplicant and iwd, however the wiki entry for wifi uses wpa_supplicant, thus I proceeded to use this tool instead of iwd.

To add my network, I used the following command:

# Enter root shell
doas su

# Generate the config and put it into the correct file
wpa_passphrase 'ExampleWifiSSID' 'ExampleWifiPassword' > /etc/wpa_supplicant/wpa_supplicant.conf

After this, I was able to test my wifi connection using:

wpa_supplicant -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

-i, I assume, is for interface and -c for config file.

After testing, wpa_supplicant was put into the background (daemon) using -B. Also I setup dhcp, using udhcpc:

# Daemonize the command above
wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

# Obtain a dhcp lease
udhcpc -i wlan0

To check, if the dchp stuff worked correctly:

ip addr show wlan0

This should now output an ip address next to the inet field.

Configuring the gateway for my wlan0 interface was pretty straight-forward. Since I will use a dhcp, I did not need to set and gateway, static ip or a subnet mask. I could just open /etc/network/interfaces and basically copy the eth0 configuration. My final file looks like this:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto wlan0
iface wlan0 inet dhcp

To now apply the configuration, first bring the interface down and then restart the networking service. Lastly bring the interface back up again:

# Bring interface down
ip link set wlan0 down

# Restart networking
rc-service networking --quiet restart &

# Bring interface up again
ip link set wlan0 up

After all of this, I finally was able to ping ivanpollak.com. This ment, that my laptop was finally ready for server usage.

Setting up an SSH server

SSH changed my life

Because this is a server, it should probably have SSH. Also, I do not want to sit in front of this computer, each time I need to administrate something.

For the implementation, I chose OpenSSH, mainly because i already knew it. Also the wiki entry used it.

Installing OpenSSH was pretty straight-forward:

doas apk add openssh

This installed the sshd service, as well as a default configuratoin in /etc/ssh/sshd_config. In the latter file, I adjusted the settings to my prefered ones (mainly setting PermitRootMode no to disable root login).

Also, because I want to disable password login altogether, I quickly needed to start the sshd-service with allowing passwords (to then copy over my ssh public key to the server).

rc-service sshd start

On my client, I now ran:

ssh-copy-id user@hostname

I quickly verified, that my passwordless login worked via ssh user@hostname. This worked and this ment, that I could throw my server into a corner in my room.

Next, I edited the /etc/ssh/sshd_config again, to not allow any logins by just using the password. This was done via the PasswordAuthentication no option.

All that was left, was to restart the service and add the service to rc-update (launch the service at boot):

doas rc-service sshd restart
rc-update add sshd

Lid-close behaviour

A standard alpine linux installation uses a basic acpid implementation. By default, there is nothing configured and thus, nothing will happen when the lid of the laptop is closed. If this is wanted, /etc/acpi.map can be created and edited. This however is out of the scope of this blog entry.

Reflecting

The process of installing alpine linux on a laptop to use as a server, might not be as easy as other operating systems. It requires a background in linux technologies and a basic understanding of errors in linux. With that said, the alpine linux wiki is very extensive and easy to read. It covers almost every question that an user might have during setup. This makes it, if you have some linux knowledge, pretty okay to install, especially if you're used to read through wiki entries.