Tags: server

Note: since I wrote this blog post, I switched to using NixOS. I’m leaving this post up because it could still hold valuable info.

This is obviously the first step, we will install the OS. I chose Archlinux. Everything here should be adaptable to other linux distributions but the locations of files could be different.

We’ll create a live USB, use it to install Arch on another server and we’ll finish by SSHing to the server using SSH keys for authentication.

Preliminaries

We need to choose a few things before starting the install. Here is what I’ll stick to in this blog post:

hostname of the server: $server
hostname of the laptop you’re currently using: $laptop
user I’ll use to connect to it: $user

I confess, there’s nothing original here but I feel like it’s easier to follow along this way. I use the convention of bash variables with the dollar prefix in the following.

Live USB

First step is to create a bootable USB that we’ll use to install Arch on the server. We’ll create two partitions, one for the OS, one for storing some files like a SSH public key that will allow us to SSH into the server without password.

Detailed instructions can be found in the Arch wiki.

Download the Arch ISO

From https://archlinux.org/download/.

Find the USB drive path

$ lsblk -p -d -o NAME,MODEL,SIZE,TRAN \
    | grep 'NAME\|usb'

Example output:

NAME         MODEL               SIZE TRAN
/dev/sda     ST9500325ASG      465.8G sata
/dev/nvme0n1 SPCC M.2 PCIe SSD 953.9G nvme

In the following, I’ll use /dev/sdX as the path. Replace it by the one you got from the command above.

Partition and format the USB drive

Create two partitions, the first one must be fat32, the second ext4.

$ fdisk /dev/sdX <<EOF
g    # use gpt table
n    # create new partition
1    # partition number
     # accept default
+3G  # 3Gb, adapt to your USB key size
t    # Change type of partition
1    #
n    # create new partiton
2    # partition number


p    # print table, to double check
w    # write table
EOF

$ mkfs.vfat -F32 /dev/sdX1
$ mkfs.ext4 -F /dev/sdX2

Write OS and files to USB drive

Mount the two partitions and the Arch ISO.

$ mkdir -p mnt/root mnt/data mnt/iso
$ mount -o rw /dev/sdX1 mnt/root
$ mount -o rw /dev/sdX2 mnt/data
$ mount -o loop arch.iso mnt/iso

Copy the files to the root partition.

$ rsync -a \
    --info=progress2 \
    --human-readable \
    --no-inc-recursive \
    mnt/iso \
    mnt/root

Create a SSH private key and public key pair and copy it to the USB key. I use Password Store as my password manager to generate and store the passphrase.

$ pass generate --clip sshkey-passphrase/$laptop/$server

$ ssh-keygen -b 4096 -i ~/.ssh/$server -N $(pass show sshkey-passphrase/$laptop/$server)
$ cp ~/.ssh/$server.pub mnt/data

I use the convention sshkey-passphrase/$laptop/$server for the location of the passphrase in my password manager.

Update the syslinux install to instruct the OS where the root partition is located.

$ uuid=$(blkid -o value -s UUID "/dev/sdX1")
$ sed -i -e \
    "s|archisolabel=.*$|archisodevice=/dev/disk/by-uuid/$uuid|" \
    "mnt/root/arch/boot/syslinux/archiso_sys.cfg"
$ syslinux-install_update -iam

Don’t forget to sync to actually write the files. This step can take a while.

$ sync

Now, let’s unmount and we can then remove the USB drive.

$ umount mnt/*

Install OS on the server

Let’s put the USB key in the server’s USB port and boot the server. I’ll assume you have brand new drives or are happy to wipe them clean.

TODO

GnuPG setup for ssh agent

OS Install