secrets

Secrets

Overview

This repository uses sops-nix with age encryption. Secrets are organized hierarchically with different access levels.

Secret Locations

Adding New Secrets

Step 1: Determine scope

Choose the appropriate secrets file based on who needs access.

Step 2: Update .sops.yaml (if new path)

If creating a new secrets file, add a rule to .sops.yaml:

- path_regex: hosts/server/newhost/
  key_groups:
    - age:
        - age1...  # newhost's SSH key as age
        - age187xlhmks2...  # admin key

Convert SSH key to age key:

ssh-to-age < hosts/server/newhost/ssh_host_ed25519_key.pub

Step 3: Add the secret

# Edit existing file
sops hosts/server/myhost/secrets.yaml

# Or create new file
sops hosts/server/newhost/secrets.yaml

Add secrets in YAML format:

MY_SECRET: "secret-value"

# Or nested
SERVICE:
  API_KEY: "key-value"
  PASSWORD: "password-value"

Step 4: Declare in Nix

sops.secrets = {
  "SERVICE/API_KEY" = { };
  "SERVICE/PASSWORD" = {
    owner = "myservice";
  };
};

Step 5: Use the secret

services.myservice = {
  apiKeyFile = config.sops.secrets."SERVICE/API_KEY".path;
};

Common Patterns

Simple secret declaration

sops.secrets = {
  "CLOUDFLARE/EMAIL" = { };
  "CLOUDFLARE/API_TOKEN" = { };
};

Custom permissions

sops.secrets."DATABASE_PASSWORD" = {
  owner = "postgres";
  group = "postgres";
  mode = "0400";
};

Using templates

Combine multiple secrets into a config file:

sops = {
  secrets = {
    "DB/USER" = { };
    "DB/PASS" = { };
  };

  templates.db-env.content = ''
    DB_USER=${config.sops.placeholder."DB/USER"}
    DB_PASS=${config.sops.placeholder."DB/PASS"}
  '';
};

services.myapp.environmentFile = config.sops.templates.db-env.path;

Restart services on secret change

sops.secrets."API_KEY" = {
  restartUnits = [ "myservice.service" ];
};

Use entire file as secret

sops.secrets."config-file" = {
  sopsFile = ./secrets.yaml;
  key = "";  # Empty key = entire file
  path = "/etc/myservice/config.yaml";
};

Key Management

Age key sources

1. Host SSH keys: Converted to age format
2. User SSH keys: In home/<user>/id_ed25519.pub
3. Admin key: Shared admin access

Converting SSH to age

# Public key to age public key
ssh-to-age < ~/.ssh/id_ed25519.pub

# Private key to age private key
ssh-to-age --private-key -i ~/.ssh/id_ed25519

Accessing Secrets in Config