path: root/content/blog/2022-10-22-alpine-linux.md

+++
date = 2022-10-22
title = "Alpine Linux: My New Server OS"
description = ""
draft = false
+++

# Alpine Linux

[Alpine Linux](https://alpinelinux.org) is a very small distro, built on musl
libc and busybox. It uses ash as the default shell, OpenRC as the init system,
and apk as the package manager. According to their website, an Alpine container
"requires no more than 8 MB and a minimal installation to disk requires around
130 MB of storage." An actual bare metal machine is recommended to have 100 MB
of RAM and 0-700 MB of storage space.

Historically, I've used Ubuntu's minimal installation image as my server OS for
the last five years. Ubuntu worked well and helped as my original server
contained an nVidia GPU and no onboard graphics, so quite a few distros won't
boot or install without a lot of tinkering.

Alpine has given me a huge increase in performance across my Docker apps and
Nginx websites. CPU load for the new server I'm using to test Alpine hovers
around 0-5% on average with an Intel(R) Core(TM) i3-6100 CPU @ 3.70GHz.

The only services I haven't moved over to Alpine are Plex Media Server and
Syncthing, which may increase CPU load quite a bit depending on how many streams
are running.

## Installation

In terms of installation, Alpine has an incredibly useful
[wiki](https://wiki.alpinelinux.org/wiki/Installation) that will guide a user
throughout the installation and post-installation processes, as well as various
other articles and guides.

To install Alpine, find an appropriate [image to
download](https://alpinelinux.org/downloads/) and flash it to a USB using
software such as Rufus or Etcher. I opted to use the Standard image for my
x86~64~ architecture.

Once the USB is ready, plug it into the machine and reboot. Note that you may
have to use a key such as `Esc` or `F1-12` to access the boot menu. The Alpine
Linux terminal will load quickly and for a login.

To log in to the installation image, use the `root` account; there is no
password. Once logged-in, execute the setup command:

```sh
setup-alpine
```

The setup script will ask a series of questions to configure the system. Be sure
to answer carefully or else you may have to re-configure the system after boot.

-   Keyboard Layout (Local keyboard language and usage mode, e.g., us and
    variant of us-nodeadkeys.)
-   Hostname (The name for the computer.)
-   Network (For example, automatic IP address discovery with the "DHCP"
    protocol.)
-   DNS Servers (Domain Name Servers to query. For privacy reasons, it is NOT
    recommended to route every local request to servers like Google's 8.8.8.8.)
-   Timezone
-   Proxy (Proxy server to use for accessing the web. Use "none" for direct
    connections to the internet.)
-   Mirror (From where to download packages. Choose the organization you trust
    giving your usage patterns to.)
-   SSH (Secure SHell remote access server. "Openssh" is part of the default
    install image. Use "none" to disable remote login, e.g. on laptops.)
-   NTP (Network Time Protocol client used for keeping the system clock in sync
    with a time-server. Package "chrony" is part of the default install image.)
-   Disk Mode (Select between diskless (disk="none"), "data" or "sys", as
    described above.)

Once the setup script is finished, be sure to reboot the machine and remove the
USB device.

```sh
reboot
```

## Post-Installation

There are many things you can do once your Alpine Linux system is up and
running, and it largely depends on what you'll use the machine for. I'm going to
walk through my personal post-installation setup for my web server.

1.  Upgrade the System

    First, login as `root` in order to update and upgrade the system:

    ```sh
    apk -U upgrade
    ```

2.  Adding a User

    I needed to add a user so that I don't need to log in as root. Note that if
    you're used to using the `sudo` command, you will now need to use the `doas`
    command on Alpine Linux.

    ```sh
    apk add doas
    adduser <username>
    adduser <username> wheel
    ```

    You can now log out and log back in using the newly-created user:

    ```sh
    exit
    ```

3.  Enable Community Packages

    In order to install more common packages that aren't found in the `main`
    repository, you will need to enable the `community` repository:

    ```sh
    doas nano /etc/apk/repositories
    ```

    Uncomment the community line for whichever version of Alpine you're running:

    ```sh
    /media/usb/apks
    http://dl-cdn.alpinelinux.org/alpine/v3.16/main
    http://dl-cdn.alpinelinux.org/alpine/v3.16/community
    #http://dl-cdn.alpinelinux.org/alpine/edge/main
    #http://dl-cdn.alpinelinux.org/alpine/edge/community
    #http://dl-cdn.alpinelinux.org/alpine/edge/testing
    ```

4.  Install Required Packages

    Now that the community packages are available, you can install any packages
    you need. In my case, I installed the web server packages I need for my
    services:

    ```sh
    doas apk add nano nginx docker docker-compose ufw
    ```

5.  SSH

    If you didn't install OpenSSH as part of the installation, you can do so
    now:

    ```sh
    doas apk add openssh
    ```

    Next, either create a new key or copy your SSH key to the server from your
    current machines:

    ```sh
    # Create a new key
    ssh-keygen
    ```

    If you need to copy an existing SSH key from a current machine:

    ```sh
    # Copy key from existing machines
    ssh-copy-id <username>@<ip_address>
    ```

6.  Firewall

    Lastly, I installed `ufw` above as my firewall. To set up, default to deny
    incoming and allow outgoing connections. Then selectively allow other ports
    or apps as needed.

    ```sh
    doas ufw default deny incoming
    doas ufw default allow outgoing
    doas ufw allow SSH
    doas ufw allow "WWW Full"
    doas ufw allow 9418 # Git server port
    ```

7.  Change Hostname

    If you don't like the hostname set during installation, you just need to
    edit two files. First, edit the simple hostname file:

    ```sh
    doas nano /etc/hostname
    ```

    ```sh
    <hostname>
    ```

    Next, edit the `hosts` file:

    ```sh
    doas nano /etc/hosts
    ```

    ```sh
    127.0.0.1   <hostname>.local <hostname> localhost.local localhost
    ::1         <hostname> <hostname>.local
    ```

# Nginx Web Server

To set up my web server, I simply created the `www` user and created the
necessary files.

```sh
doas adduser -D -g 'www' www
mkdir /www
doas mkdir /www
doas chown -R www:www /var/lib/nginx/
doas chown -R www:www /www
```

If you're running a simple webroot, you can alter the main `nginx.conf` file.
Otherwise, you can drop configuration files in the following directory. You
don't need to enable or symlink the configuration file like you do in other
systems.

```sh
doas nano /etc/nginx/http.d/example_website.conf
```

Once the configuration is set and pointed at the `/www` directory to serve
files, enable the Nginx service:

```sh
# Note that 'default' must be included or Nginx will not start on boot
doas rc-update add nginx default
```

# Docker Containers

Docker works exactly the same as other systems. Either execute a `docker run`
command or create a `docker-compose.yml` file and do `docker-compose up -d`.

# Git Server

I went in-depth on how to self-host a git server in another post: [Self-Hosting
a Personal Git Server](../git-server/).

However, there are a few differences with Alpine. First note that in order to
change the `git` user's shell, you must do a few things a little different:

```sh
doas apk add libuser
doas touch /etc/login.defs
doas mkdir /etc/default
doas touch /etc/default/useradd
doas lchsh git
```

# Thoughts on Alpine

So far, I love Alpine Linux. I have no complaints about anything at this point,
but I'm not completely finished with the migration yet. Once I'm able to upgrade
my hardware to a rack-mounted server, I will migrate Plex and Syncthing over to
Alpine as well - possibly putting Plex into a container or VM.

The performance is stellar, the `apk` package manager is seamless, and system
administration tasks are effortless. My only regret is that I didn't install
Alpine sooner.