nixos/scripts/bootstrap.sh

#!/usr/bin/env bash

echo -e "
Before using this tool, ensure that the host has been setup correctly.
Boot the latest Nixos-minimal install ISO on the host and access the tty.

Use 'ip a' to get the ip address, then 'sudo su' to change to root. Finally
Run 'passwd' and set a temporary password (something simple like '1234') 
for the root user.
"

read -p "Confirm host had been setup using the above steps...(yes|no): " confirm
[ "$confirm" != "yes" ] && echo "Exiting" && exit 0

cd ~
read -p "Enter hostname: " hostname
read -p "Enter username: " username
read -p "Enter ip address: " ip
read -p "Enter nixosSystem to build, e.g. 'bootstrap': " config

KEY_DIR="$HOME/keys/$hostname/"
mkdir -p $KEY_DIR

echo "Creating ssh keys for new host."
KEY_NAME="$username@$hostname-ssh-ed25519"

KNOWN_HOSTS=$(grep "$ip" ~/.ssh/known_hosts)
confirm_delete=""

[ "$KNOWN_HOSTS" != "" ] && echo -e "Host found in: ~/.ssh/known_hosts\n\n$KNOWN_HOSTS\n" && read -p "Delete existing hosts from ~/.ssh/known_hosts? (yes|no) " confirm_delete
[ "$confirm_delete" = "yes" ] && sed -i "/$ip/d" ~/.ssh/known_hosts 

echo "Copying deploy_key pubkey to target host"
ssh-copy-id -i "$(readlink -n "$HOME/.ssh/deploy_key-ssh-ed25519.pub" )" "root@$ip"

overwrite=""
[ -f "$KEY_DIR/$KEY_NAME" ] && read -p "Key exists, would you like to overwrite it? (yes|no) " overwrite

[  -z "$overwrite" ] || [ "$overwrite" == "yes" ] && ssh-keygen -t ed25519 -f "$KEY_DIR/$KEY_NAME" -C "$username@$hostname" -N ""

echo "Copying ssh key to target host:"
scp -i "$KEY_DIR/$KEY_NAME"* "root@$ip:/etc/ssh/"
[ $? != 0 ] && echo "Error copying keys to target host" && exit 1

echo "Generating age key from ssh key"
nix-shell -p ssh-to-age --run "cat $KEY_DIR/$KEY_NAME.pub | ssh-to-age > $KEY_DIR/age_key_$hostname"
[ $? != 0 ] && echo "Error generating age key" && exit 1

AGE_KEY=$(cat "$KEY_DIR/age_key_$hostname")

echo -e "Age key:\n$AGE_KEY\n"
echo "This needs to be inserted into .sops.yaml file."

# Install Nixos bootstrap
cd "$HOME/nixos"
SHELL=/bin/sh nix run github:nix-community/nixos-anywhere -- --flake .#"$config" root@"$ip" -i "$KEY_DIR/ssh_ed25519_key_$hostname"
[ $? != 0 ] && echo "Error installing Nixos" && exit 1

echo "Deleting host from known_hosts"
sed -i "/$ip/d" ~/.ssh/known_hosts

while true;
do
  read -p "Confirm live CD has been removed... (yes|no)" confirm
  [ "$confirm" = "yes" ] && break
done

echo "Waiting for $ip to come back online and port 22 to be open..."

while ! ping -c 1 $ip &> /dev/null || ! nc -zvw3 $ip 22 &> /dev/null
do
    echo "$ip is still offline or port 22 is not open. Checking again in 5 seconds..."
    sleep 5
done

echo "$ip is now online and port 22 is open!"

echo "Configuring ssh keys on target host to enable connection to gitea:"
ssh-copy-id -i "$HOME/.ssh/deploy_key-ssh-ed25519.pub" "$username@$ip"
read -r -d '' config << EOM
Host git.bitlab21.com
    IdentitiesOnly yes
    StrictHostKeyChecking no
    IdentityFile ~/.ssh/deploy_key-ssh-ed25519
EOM

# Append the string to file on target machine
echo "$config" | ssh "$username@$ip" 'mkdir -p ~/.ssh/ && cat > ~/.ssh/config'

echo -e "
Complete!

Now add the age key to .sops.yaml, like this:
keys:
- &hosts:
    - &$hostname $AGE_KEY

creation_rules:
  - path_regex: secrets.yaml$
    key_groups:
      - age:
        - *$hostname

Then to update the keys for the secrets.yaml file, run:
'sops --config .sops.yaml updatekeys secrets.yaml'
or with nix-shell:
'nix-shell -p sops --run 'sops --config .sops.yaml updatekeys secrets.yaml''
then run 'nix flake lock --update-input nix-secrets $HOME/nixos'
Finally, commit and push these changes to remote so they can be accessed on
the new host.
"

while true;
do
  read -p "Confirm keys have been added to .sops.yaml using the above steps, and the changes (if any) have been commited and pushed...(yes|no): " confirm
  [ "$confirm" = "yes" ] && break
done

echo "Copying gitea private ssh key to host"
echo "New password is 'nixos'"

rsync -av "$(readlink -n "$HOME/.ssh/deploy_key-ssh-ed25519" )" "$username@$ip":~/.ssh/deploy_key-ssh-ed25519
ssh "$username@$ip" "nix-shell -p git --run 'git clone git@git.bitlab21.com:sam/nixos.git'"
ssh "$username@$ip" "nix-shell -p git --run 'git clone git@git.bitlab21.com:sam/nix-secrets.git'"

echo "Successfully installed Nixos on the target host!"
echo "Please remote into the new host and run 'sudo nixos-generate-config && cp /etc/nixos/hardware-configuration.nix /home/$username/nixos/hosts/$hostname/'"