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@ -33,28 +33,11 @@ environment variables that can be passed to sops.
There is a `configuration.nix` example in the [deployment step](#deploy-example) of our usage example.
## Supported encryption methods
## Installation
sops-nix supports two basic ways of encryption, GPG and `age`.
Choose one of the following methods. When using it non-globally with home-manager, refer to [Use with home-manager](./docs/InDepthUsage.md#use-with-home-manager).
GPG is based on [GnuPG](https://gnupg.org/) and encrypts against GPG public keys. Private GPG keys may
be used to decrypt the secrets on the target machine. The tool [`ssh-to-pgp`](https://github.com/Mic92/ssh-to-pgp) can
be used to derive a GPG key from a SSH (host) key in RSA format.
The other method is `age` which is based on [`age`](https://github.com/FiloSottile/age).
The tool ([`ssh-to-age`](https://github.com/Mic92/ssh-to-age)) can convert SSH host or user keys in Ed25519
format to `age` keys.
## Usage example
If you prefer video over the textual description below, you can also checkout this [6min tutorial](https://www.youtube.com/watch?v=G5f6GC7SnhU) by [@vimjoyer](https://github.com/vimjoyer).
<details>
<summary><b>1. Install sops-nix</b></summary>
Choose one of the following methods. When using it non-globally with home-manager, refer to [Use with home-manager](#use-with-home-manager).
#### Flakes (current recommendation)
### Flakes (current recommendation)
If you use experimental nix flakes support:
@ -77,9 +60,14 @@ If you use experimental nix flakes support:
}
```
##### [`nix-darwin`](https://github.com/nix-darwin/nix-darwin)
### Alternative Installs
A module for `nix-darwin` is also available for global install with flakes:
<details>
<summary><b>Nix Darwin (MacOS Users)</b></summary>
See [`nix-darwin`](https://github.com/nix-darwin/nix-darwin) for background info.
A module for `nix-darwin` is available for global install with flakes:
```nix
{
@ -99,9 +87,13 @@ A module for `nix-darwin` is also available for global install with flakes:
};
}
```
</details>
<details>
<summary><b>Niv (recommended if not using flakes)</b></summary>
#### [`niv`](https://github.com/nmattia/niv) (recommended if not using flakes)
First add it to niv:
See [`niv`](https://github.com/nmattia/niv) (recommended if not using flakes)
First add it to niv:
```console
$ niv add Mic92/sops-nix
@ -114,10 +106,11 @@ $ niv add Mic92/sops-nix
imports = [ "${(import ./nix/sources.nix).sops-nix}/modules/sops" ];
}
```
#### `fetchTarball`
</details>
<details>
<summary><b>fetchTarball (None of the above)</b></summary>
Add the following to your `configuration.nix`:
Add the following to your `configuration.nix`:
```nix
{
@ -133,339 +126,57 @@ $ niv add Mic92/sops-nix
];
}
```
</details>
<details>
<summary><b>2. Generate a key for yourself</b></summary>
## Usage
This key will be used for you to edit secrets.
`sops-nix` supports two basic ways of encryption, GPG and `age`.
You can generate yourself a key:
First, pick your track. If you have time, there are some excellent resources on each key type that we won't cover here.
```console
# for age..
$ mkdir -p ~/.config/sops/age
$ age-keygen -o ~/.config/sops/age/keys.txt
# or to convert an ssh ed25519 key to an age key
$ mkdir -p ~/.config/sops/age
$ nix-shell -p ssh-to-age --run "ssh-to-age -private-key -i ~/.ssh/id_ed25519 > ~/.config/sops/age/keys.txt"
# for GPG >= version 2.1.17
$ gpg --full-generate-key
# for GPG < 2.1.17
$ gpg --default-new-key-algo rsa4096 --gen-key
```
1. [`age`](https://github.com/FiloSottile/age)
2. [GnuPG](https://gnupg.org/)
3. SSH
- [`ssh-to-age`](https://github.com/Mic92/ssh-to-age) (automatic conversion)
- [`ssh-to-pgp`](https://github.com/Mic92/ssh-to-pgp) (manual conversion)
Or you can use the `ssh-to-pgp` tool to get a GPG key from an SSH key:
```console
$ nix-shell -p gnupg -p ssh-to-pgp --run "ssh-to-pgp -private-key -i $HOME/.ssh/id_rsa | gpg --import --quiet"
2504791468b153b8a3963cc97ba53d1919c5dfd4
# This exports the public key
$ nix-shell -p ssh-to-pgp --run "ssh-to-pgp -i $HOME/.ssh/id_rsa -o $USER.asc"
2504791468b153b8a3963cc97ba53d1919c5dfd4
```
(Note that `ssh-to-pgp` only supports RSA keys; to use Ed25519 keys, use `age`.)
If you get the following,
```console
ssh-to-pgp: failed to parse private ssh key: ssh: this private key is passphrase protected
```
then your SSH key is encrypted with your password and you will need to create an unencrypted copy temporarily.
```console
$ cp $HOME/.ssh/id_rsa /tmp/id_rsa
$ ssh-keygen -p -N "" -f /tmp/id_rsa
$ nix-shell -p gnupg -p ssh-to-pgp --run "ssh-to-pgp -private-key -i /tmp/id_rsa | gpg --import --quiet"
$ rm /tmp/id_rsa
```
```mermaid
---
config:
look: classic
theme: dark
layout: dagre
---
graph TD;
Start[Start]
When using `nix-darwin` save the `age` key to `$HOME/Library/Application Support/sops/age/keys.txt` or set a [custom](https://github.com/getsops/sops#23encrypting-using-age) configuration directory.
ageLink[Age How-To]
click ageLink href "./docs/HowTo_age.md"
<details>
<summary> How to find the public key of an `age` key </summary>
sshLink[SSH How-To]
click ageLink href "./docs/HowTo_ssh.md"
If you generated an `age` key, the `age` public key can be found via `age-keygen -y $PATH_TO_KEY`:
```console
$ age-keygen -y ~/.config/sops/age/keys.txt
age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxl
```
gpgLink[GPG How-To]
click ageLink href "./docs/HowTo_gpg.md"
Otherwise, you can convert an existing SSH key into an `age` public key:
```console
$ nix-shell -p ssh-to-age --run "ssh-to-age < ~/.ssh/id_ed25519.pub"
# or
$ nix-shell -p ssh-to-age --run "ssh-add -L | ssh-to-age"
```
Decision1{I have opinions
on key types}
Start --> Decision1
</details>
Decision1 -->|No| Decision2{I already
use SSH}
<details>
<summary> How to find the GPG fingerprint of a key </summary>
Decision1 -->|Yes| Know{Click
a tutorial}
Invoke this command and look for your key:
```console
$ gpg --list-secret-keys
/tmp/tmp.JA07D1aVRD/pubring.kbx
-------------------------------
sec rsa2048 1970-01-01 [SCE]
9F89C5F69A10281A835014B09C3DC61F752087EF
uid [ unknown] root <root@localhost>
```
Know -->|Age| ageLink
Know -->|SSH| sshLink
Know -->|GPG| gpgLink
The fingerprint here is `9F89C5F69A10281A835014B09C3DC61F752087EF`.
</details>
Your `age` public key or GPG fingerprint can be written to your [`.sops.yaml`](https://github.com/getsops/sops#using-sops-yaml-conf-to-select-kms-pgp-and-age-for-new-files) in the root of your configuration directory or repository:
```yaml
# This example uses YAML anchors which allows reuse of multiple keys
# without having to repeat yourself.
# Also see https://github.com/Mic92/dotfiles/blob/d6114726d859df36ccaa32891c4963ae5717ef7f/nixos/.sops.yaml
# for a more complex example.
keys:
- &admin_alice 2504791468b153b8a3963cc97ba53d1919c5dfd4
- &admin_bob age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxl
creation_rules:
- path_regex: secrets/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
- *admin_alice
age:
- *admin_bob
```
**Note:**
Be sure to not include a `-` before subsequent key types under `key_groups`
(i.e. `age` in the above example should not have a `-` in front).
This will otherwise cause sops to require multiple keys (shamir secret sharing)
to decrypt a secret, which breaks normal sops-nix usage.
</details>
<details>
<summary><b>3. Get a public key for your target machine</b></summary>
The easiest way to add new machines is by using SSH host keys (this requires OpenSSH to be enabled).
If you are using `age`, the `ssh-to-age` tool can be used to convert any SSH Ed25519 public key to the `age` format:
```console
$ nix-shell -p ssh-to-age --run 'ssh-keyscan example.com | ssh-to-age'
age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3
$ nix-shell -p ssh-to-age --run 'cat /etc/ssh/ssh_host_ed25519_key.pub | ssh-to-age'
age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3
```
For GPG, since sops does not natively support SSH keys yet, sops-nix supports a conversion tool (`ssh-to-pgp`) to store them as GPG keys:
```console
$ ssh root@server01 "cat /etc/ssh/ssh_host_rsa_key" | nix-shell -p ssh-to-pgp --run "ssh-to-pgp -o server01.asc"
# or with sudo
$ ssh youruser@server01 "sudo cat /etc/ssh/ssh_host_rsa_key" | nix-shell -p ssh-to-pgp --run "ssh-to-pgp -o server01.asc"
0fd60c8c3b664aceb1796ce02b318df330331003
# or just read them locally/over ssh
$ nix-shell -p ssh-to-pgp --run "ssh-to-pgp -i /etc/ssh/ssh_host_rsa_key -o server01.asc"
0fd60c8c3b664aceb1796ce02b318df330331003
```
The output of these commands is the identifier for the server's key, which can be added to your `.sops.yaml`:
```yaml
keys:
- &admin_alice 2504791468b153b8a3963cc97ba53d1919c5dfd4
- &admin_bob age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxl
- &server_azmidi 0fd60c8c3b664aceb1796ce02b318df330331003
- &server_nosaxa age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3
creation_rules:
- path_regex: secrets/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
- *admin_alice
- *server_azmidi
age:
- *admin_bob
- *server_nosaxa
- path_regex: secrets/azmidi/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
- *admin_alice
- *server_azmidi
age:
- *admin_bob
```
If you prefer having a separate GPG key, see [Use with GPG instead of SSH keys](#use-with-GPG-instead-of-SSH-keys).
</details>
<details>
<summary><b>4. Create a sops file</b></summary>
To create a sops file you need write a `.sops.yaml` as described above.
When using GnuPG you also need to import your personal GPG key
(and your colleagues) and your servers into your GPG key chain.
<details>
<summary>sops-nix can automate the import of GPG keys with a hook for nix-shell, allowing public
keys to be shared via version control (i.e. git).</summary>
```nix
# shell.nix
with import <nixpkgs> {};
let
sops-nix = builtins.fetchTarball {
url = "https://github.com/Mic92/sops-nix/archive/master.tar.gz";
};
in
mkShell {
# imports all files ending in .asc/.gpg
sopsPGPKeyDirs = [
"${toString ./.}/keys/hosts"
"${toString ./.}/keys/users"
];
# Also single files can be imported.
#sopsPGPKeys = [
# "${toString ./.}/keys/users/mic92.asc"
# "${toString ./.}/keys/hosts/server01.asc"
#];
# This hook can also import gpg keys into its own seperate
# gpg keyring instead of using the default one. This allows
# to isolate otherwise unrelated server keys from the user gpg keychain.
# By uncommenting the following lines, it will set GNUPGHOME
# to .git/gnupg.
# Storing it inside .git prevents accedentially commiting private keys.
# After setting this option you will also need to import your own
# private key into keyring, i.e. using a a command like this
# (replacing 0000000000000000000000000000000000000000 with your fingerprint)
# $ (unset GNUPGHOME; gpg --armor --export-secret-key 0000000000000000000000000000000000000000) | gpg --import
#sopsCreateGPGHome = true;
# To use a different directory for gpg dirs set sopsGPGHome
#sopsGPGHome = "${toString ./.}/../gnupg";
nativeBuildInputs = [
(pkgs.callPackage sops-nix {}).sops-import-keys-hook
];
}
```
A valid directory structure for this might look like:
```console
$ tree .
.
├── keys
│   ├── hosts
│   │   └── server01.asc
│   └── users
│   └── mic92.asc
```
</details>
After configuring `.sops.yaml`, you can open a new file with sops:
```console
$ nix-shell -p sops --run "sops secrets/example.yaml"
```
This will start your configured editor located at the `$EDITOR` environment variable.
An example secret file might be:
```yaml
# Files must always have a string value
example-key: example-value
# Nesting the key results in the creation of directories.
# These directories will be owned by root:keys and have permissions 0751.
myservice:
my_subdir:
my_secret: password1
```
An example result when saving this file could be:
Decision2 -->|Yes| sshLink
Decision2 -->|No| ageLink
```
example-key: ENC[AES256_GCM,data:AB8XMyid4P7mXdjj+A==,iv:RRsZC+V+3w22pOi/2TCjBYn/0OYsNGCu5CT1ZBSKGi0=,tag:zT5mlujrSuA6KKxLKL8CMQ==,type:str]
#ENC[AES256_GCM,data:59QWbzCQCP7kLdhyjFOZe503MgegN0kv505PBNHwjp6aYztDHwx2N9+A1Bz6G/vWYo+4LpBo8/s=,iv:89q3ZXgM1wBUg5G29ROor3VXrO3QFGCvfwDoA3+G14M=,tag:hOSnEZ6DKycnF37LCXOjzg==,type:comment]
#ENC[AES256_GCM,data:kUuJCkDE9JT9C+kdNe0CSB3c+gmgE4We1OoX4C1dWeoZCw/o9/09CzjRi9eOBUEL0P1lrt+g6V2uXFVq4n+M8UPGUAbRUr3A,iv:nXJS8wqi+ephoLynm9Nxbqan0V5dBstctqP0WxniSOw=,tag:ALx396Z/IPCwnlqH//Hj3g==,type:comment]
myservice:
my_subdir:
my_secret: ENC[AES256_GCM,data:hcRk5ERw60G5,iv:3Ur6iH1Yu0eu2otcEv+hGRF5kTaH6HSlrofJ5JXvewA=,tag:hpECXFnMhGNnAxxzuGW5jg==,type:str]
sops:
kms: []
gcp_kms: []
azure_kv: []
hc_vault: []
age:
- recipient: age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxl
enc: |
-----BEGIN AGE ENCRYPTED FILE-----
YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSB1dFYvSTRHa3IwTVpuZjEz
SDZZQnc5a0dGVGEzNXZmNEY5NlZDbVgyNVU0Clo3ZC9MRGp4SHhLUTVCeWlOUUxS
MEtPdW4rUHhjdFB6bFhyUXRQTkRpWjAKLS0tIDVTbWU2V3dJNUZrK1A5U0c5bkc0
S3VINUJYc3VKcjBZbHVqcGJBSlVPZWcKqPXE01ienWDbTwxo+z4dNAizR3t6uTS+
KbmSOK1v61Ri0bsM5HItiMP+fE3VCyhqMBmPdcrR92+3oBmiSFnXPA==
-----END AGE ENCRYPTED FILE-----
- recipient: age18jtffqax5v0t6ehh4ypaefl4mfhcrhn6ek3p80mhfp9psx6pd35qew2ww3
enc: |
-----BEGIN AGE ENCRYPTED FILE-----
YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBzT3FxcDEzaFRQOVFpNkg2
Skw4WEIxZzNTWkNBaDRhcUN2ejY4QTAwTERvCkx2clIzT2wyaFJZcjl0RkFXL2p6
enhqVEZ3ZkNKUU5jTlUxRC9Lb090TzAKLS0tIDBEaG00RFJDZ3ZVVjBGUWJkRHdQ
YkpudG43eURPVWJUejd3Znk5Z29lWlkK0cIngn2qdmiOE5rHOHxTRcjfZYuY3Ej7
Yy7nYxMwTdYsm/V6Lp2xm8hvSzBEIFL+JXnSTSwSHnCIfgle5BRbug==
-----END AGE ENCRYPTED FILE-----
lastmodified: "2021-11-20T16:21:10Z"
mac: ENC[AES256_GCM,data:5ieT/yv1GZfZFr+OAZ/DBF+6DJHijRXpjNI2kfBun3KxDkyjiu/OFmAbsoVFY/y6YCT3ofl4Vwa56Veo3iYj4njgxyLpLuD1B6zkMaNXaPywbAhuMho7bDGEJZHrlYOUNLdBqW2ytTuFA095IncXE8CFGr38A2hfjcputdHk4R4=,iv:UcBXWtaquflQFNDphZUqahADkeege5OjUY38pLIcFkU=,tag:yy+HSMm+xtX+vHO78nej5w==,type:str]
pgp: []
unencrypted_suffix: _unencrypted
version: 3.7.1
```
If you add a new host to your `.sops.yaml` file, you will need to update the keys for all secrets that are used by the new host. This can be done like so:
```
$ nix-shell -p sops --run "sops updatekeys secrets/example.yaml"
```
</details>
<details>
<summary id="deploy-example"><b>5. Deploy</b></summary>
If you derived your server public key from SSH, all you need in your `configuration.nix` is:
```nix
{
# This will add secrets.yml to the nix store
# You can avoid this by adding a string to the full path instead, i.e.
# sops.defaultSopsFile = "/root/.sops/secrets/example.yaml";
sops.defaultSopsFile = ./secrets/example.yaml;
# This will automatically import SSH keys as age keys
sops.age.sshKeyPaths = [ "/etc/ssh/ssh_host_ed25519_key" ];
# This is using an age key that is expected to already be in the filesystem
sops.age.keyFile = "/var/lib/sops-nix/key.txt";
# This will generate a new key if the key specified above does not exist
sops.age.generateKey = true;
# This is the actual specification of the secrets.
sops.secrets.example-key = {};
sops.secrets."myservice/my_subdir/my_secret" = {};
}
```
On `nixos-rebuild switch` this will make the keys accessible
via `/run/secrets/example-key` and `/run/secrets/myservice/my_subdir/my_secret`:
```console
$ cat /run/secrets/example-key
example-value
$ cat /run/secrets/myservice/my_subdir/my_secret
password1
```
`/run/secrets` is a symlink to `/run/secrets.d/{number}`:
```console
$ ls -la /run/secrets
lrwxrwxrwx 16 root 12 Jul 6:23  /run/secrets -> /run/secrets.d/1
```
</details>
## Set secret permission/owner and allow services to access it

198
docs/HowTo_sshToAge.md Normal file
View file

@ -0,0 +1,198 @@
# How-To: `sops-nix` with an age key
This guide assumes you are starting from scratch and are on Linux.
Nix Darwin users -- check appropriate hidden sections to ensure compatibility.
If you already know
## 1. Generate a base key
This key will be used for you to edit secrets. Be careful not to overwrite an existing key you might be using for other purposes (ex. a github credential).
```bash
ssh-keygen -t ed25519 # optional: add `-f [path/to/your/key]
```
## 2. Derive an age key:
```bash
# Convert an ssh ed25519 key to an age key
mkdir -p ~/.config/sops/age
nix-shell -p ssh-to-age --run "ssh-to-age \
-private-key -i ~/.ssh/id_ed25519 \
> ~/.config/sops/age/keys.txt"
```
<details>
<summary>Troubleshooting: encrypted ssh key </summary>
If you get the following,
```console
ssh-to-age: failed to parse private ssh key: ssh: this private key is passphrase protected
```
then your SSH key is encrypted with your password and you will need to create an unencrypted copy temporarily.
```console
$ cp $HOME/.ssh/id_rsa /tmp/id_rsa
$ ssh-keygen -p -N "" -f /tmp/id_rsa
$ nix-shell -p gnupg -p ssh-to-pgp --run "ssh-to-pgp -private-key -i /tmp/id_rsa | gpg --import --quiet"
$ rm /tmp/id_rsa
```
</details>
<details><summary>Troubleshooting: Nix Darwin paths</summary>
When using `nix-darwin` save the `age` key to `$HOME/Library/Application Support/sops/age/keys.txt` or set a [custom](https://github.com/getsops/sops#23encrypting-using-age) configuration directory.
```bash
# Modified to use stock nix-darwin path
mkdir -p ~/.config/sops/age
nix-shell -p ssh-to-age --run "ssh-to-age \
-private-key -i ~/.ssh/id_ed25519 \
> $HOME/Library/Application Support/sops/age/keys.txt"
```
</details>
## 3. Find an `age` public key
Derive `age` public key directly from the source ssh key:
```bash
nix-shell -p ssh-to-age --run "ssh-to-age < ~/.ssh/id_ed25519.pub"
# Expected output:
# age[key....................................................]
```
## Create a sops file
```yaml
keys:
- &server_arpanet age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxl
creation_rules:
- path_regex: secrets/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
age:
- *server_arpanet
- path_regex: secrets/azmidi/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
- *admin_alice
- *server_azmidi
age:
- *admin_bob
```
## 4. Add your first Secret
```bash
# In the same directory as your .sops.yaml
# Passing paths is possible via --config,
# but a path_regex must match relative to your $(pwd)
# This will open `secrets/example.yml` in your $EDITOR and encrypt the saved file on exit
sops edit secrets/public-ips.yml
```
Example yaml:
```yaml
my-server:
public-ip:
"1.2.3.4"
```
## 5. Add secrets to your config
For the ssh-to-age use case, the config is simple:
```nix
# /etc/nixos/getSecrets.nix
{
# This will add secrets/public-ips.yaml to the nix store
# You can avoid this by adding a string to the full path instead, i.e.
# sops.defaultSopsFile = "/root/.sops/secrets/public-ips.yaml";
sops.defaultSopsFile = ./secrets/public-ips.yaml;
# This will automatically import SSH keys as age keys
sops.age.sshKeyPaths = [ "/etc/ssh/ssh_host_ed25519_key" ];
# This is using an age key that is expected to already be in the filesystem
sops.age.keyFile = "/var/lib/sops-nix/key.txt";
# This will generate a new key if the key specified above does not exist
sops.age.generateKey = true;
# This is the actual specification of the secrets.
sops.secrets.my-server = {};
sops.secrets."myservice/my_subdir/my_secret" = {};
}
```
Example usage:
```nix
# /etc/nixos/staticHosts.nix
{config, ...}:{
networking.hosts = {
"${config.sops.secrets.ips.my-server.public-ip}" = [ "my.site.org" ];
};
}
```
Don't forget to include the files above in your config!
```nix
# /etc/nixos/configuration.nix
{
imports = [
./getSecrets.nix
./staticHosts.nix
# ... rest of your imports
]
# ... rest of your config
}
```
## 6. Deploy
Rebuild your system:
```bash
nixos-rebuild switch # --flake .
```
This will make the keys accessible under `/run/secrets/`.
If you followed this guide exactly, youll find the following files:
- `/run/secrets/my-server/[secret]`
- `/run/secrets/myservice/my_subdir/[secret]`
Validate that they are available in plaintext woth a simple `cat` (you might need to prefix `sudo` depending on permissions):
```bash
cat /run/secrets/my-server
# Expected output:
# example-value
cat /run/secrets/myservice/my_subdir/my_secret
# Expected output:
# password1
```
`/run/secrets` is a symlink to `/run/secrets.d/{number}`:
```bash
ls -la /run/secrets
# Expected output:
# lrwxrwxrwx 16 root 12 Jul 6:23  /run/secrets -> /run/secrets.d/1
```
## Further Reading
If you've made it this far -- check out the [In-Depth Usage Guide](./InDepthUsage.md) for more details.

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# `sops-nix` In-Depth Usage
This is a collection of useful walkthroughs in no particular order. Reference the table of contents as you need.
- [Get a public key from a target machine](#get-a-public-key-from-a-target-machine)
- [Set secret permission/owner and allow services to access it](#Set-secret-permission-/-owner-and-allow-services-to-access-it)
- [Restarting/reloading systemd units on secret change](#Restarting-/-reloading-systemd-units-on-secret-change)
- [Symlinks to other directories](#symlinks-to-other-directories)
- [Setting a user's password](#setting-a-users-password)
- [Different file formats](#different-file-formats)
-[Emit plain file for yaml and json formats](#emit-plain-file-for-yaml-and-json-formats)
- [Use with home manager](#use-with-home-manager)
- [Use with GPG instead of SSH keys](#use-with-gpg-instead-of-ssh-keys)
- [Share secrets between different users](#share-secrets-between-different-users)
- [Migrate from pass/krops](#migrate-from-passkrops)
- [Real-world examples](#real-world-examples)
- [Known limitations](#known-limitations)
- [Templates](#templates)
## Get a public key from a target machine
The easiest way to add new machines is by using SSH host keys (this requires OpenSSH to be enabled).
If you are using `age`, the `ssh-to-age` tool can be used to convert any SSH Ed25519 public key to the `age` format:
```console
$ nix-shell -p ssh-to-age --run 'ssh-keyscan example.com | ssh-to-age'
age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3
$ nix-shell -p ssh-to-age --run 'cat /etc/ssh/ssh_host_ed25519_key.pub | ssh-to-age'
age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3
```
For GPG, since sops does not natively support SSH keys yet, sops-nix supports a conversion tool (`ssh-to-pgp`) to store them as GPG keys:
```console
$ ssh root@server01 "cat /etc/ssh/ssh_host_rsa_key" | nix-shell -p ssh-to-pgp --run "ssh-to-pgp -o server01.asc"
# or with sudo
$ ssh youruser@server01 "sudo cat /etc/ssh/ssh_host_rsa_key" | nix-shell -p ssh-to-pgp --run "ssh-to-pgp -o server01.asc"
0fd60c8c3b664aceb1796ce02b318df330331003
# or just read them locally/over ssh
$ nix-shell -p ssh-to-pgp --run "ssh-to-pgp -i /etc/ssh/ssh_host_rsa_key -o server01.asc"
0fd60c8c3b664aceb1796ce02b318df330331003
```
The output of these commands is the identifier for the server's key, which can be added to your `.sops.yaml`:
```yaml
keys:
- &admin_alice 2504791468b153b8a3963cc97ba53d1919c5dfd4
- &admin_bob age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxl
- &server_azmidi 0fd60c8c3b664aceb1796ce02b318df330331003
- &server_nosaxa age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3
creation_rules:
- path_regex: secrets/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
- *admin_alice
- *server_azmidi
age:
- *admin_bob
- *server_nosaxa
- path_regex: secrets/azmidi/[^/]+\.(yaml|json|env|ini)$
key_groups:
- pgp:
- *admin_alice
- *server_azmidi
age:
- *admin_bob
```
If you prefer having a separate GPG key, see [Use with GPG instead of SSH keys](#use-with-GPG-instead-of-SSH-keys).
## Set secret permission/owner and allow services to access it
By default secrets are owned by `root:root`. Furthermore
the parent directory `/run/secrets.d` is only owned by
`root` and the `keys` group has read access to it:
``` console
$ ls -la /run/secrets.d/1
total 24
drwxr-x--- 2 root keys 0 Jul 12 6:23 .
drwxr-x--- 3 root keys 0 Jul 12 6:23 ..
-r-------- 1 root root 20 Jul 12 6:23 example-secret
```
The secrets option has further parameter to change secret permission.
Consider the following nixos configuration example:
```nix
{
# Permission modes are in octal representation (same as chmod),
# the digits represent: user|group|others
# 7 - full (rwx)
# 6 - read and write (rw-)
# 5 - read and execute (r-x)
# 4 - read only (r--)
# 3 - write and execute (-wx)
# 2 - write only (-w-)
# 1 - execute only (--x)
# 0 - none (---)
sops.secrets.example-secret.mode = "0440";
# Either a user id or group name representation of the secret owner
# It is recommended to get the user name from `config.users.users.<?name>.name` to avoid misconfiguration
sops.secrets.example-secret.owner = config.users.users.nobody.name;
# Either the group id or group name representation of the secret group
# It is recommended to get the group name from `config.users.users.<?name>.group` to avoid misconfiguration
sops.secrets.example-secret.group = config.users.users.nobody.group;
}
```
<details>
<summary>This example configures secrets for buildkite, a CI agent;
the service needs a token and a SSH private key to function.</summary>
```nix
{ pkgs, config, ... }:
{
services.buildkite-agents.builder = {
enable = true;
tokenPath = config.sops.secrets.buildkite-token.path;
privateSshKeyPath = config.sops.secrets.buildkite-ssh-key.path;
runtimePackages = [
pkgs.gnutar
pkgs.bash
pkgs.nix
pkgs.gzip
pkgs.git
];
};
sops.secrets.buildkite-token.owner = config.users.buildkite-agent-builder.name;
sops.secrets.buildkite-ssh-key.owner = config.users.buildkite-agent-builder.name;
}
```
</details>
## Restarting/reloading systemd units on secret change
It is possible to restart or reload units when a secret changes or is newly initialized.
This behavior can be configured per-secret:
```nix
{
sops.secrets."home-assistant-secrets.yaml" = {
restartUnits = [ "home-assistant.service" ];
# there is also `reloadUnits` which acts like a `reloadTrigger` in a NixOS systemd service
};
}
```
## Symlinks to other directories
Some services might expect files in certain locations.
Using the `path` option a symlink to this directory can
be created:
```nix
{
sops.secrets."home-assistant-secrets.yaml" = {
owner = "hass";
path = "/var/lib/hass/secrets.yaml";
};
}
```
```console
$ ls -la /var/lib/hass/secrets.yaml
lrwxrwxrwx 1 root root 40 Jul 19 22:36 /var/lib/hass/secrets.yaml -> /run/secrets/home-assistant-secrets.yaml
```
## Setting a user's password
sops-nix has to run after NixOS creates users (in order to specify what users own a secret.)
This means that it's not possible to set `users.users.<name>.hashedPasswordFile` to any secrets managed by sops-nix.
To work around this issue, it's possible to set `neededForUsers = true` in a secret.
This will cause the secret to be decrypted to `/run/secrets-for-users` instead of `/run/secrets` before NixOS creates users.
As users are not created yet, it's not possible to set an owner for these secrets.
The password must be stored as a hash for this to work, which can be created with the command `mkpasswd`
```console
$ echo "password" | mkpasswd -s
$y$j9T$WFoiErKnEnMcGq0ruQK4K.$4nJAY3LBeBsZBTYSkdTOejKU6KlDmhnfUV3Ll1K/1b.
```
```nix
{ config, ... }: {
sops.secrets.my-password.neededForUsers = true;
users.users.mic92 = {
isNormalUser = true;
hashedPasswordFile = config.sops.secrets.my-password.path;
};
}
```
**Note:** If you are using Impermanence, the key used for secret decryption (`sops.age.keyFile`, or the host SSH keys) must be in a persisted directory,
loaded early enough during boot. For example:
```nix
sops.age.keyFile = "/nix/persist/var/lib/sops-nix/key.txt";
```
or:
```nix
fileSystems."/etc/ssh".neededForBoot = true;
```
## Different file formats
At the moment we support the following file formats: YAML, JSON, INI, dotenv and binary.
sops-nix allows specifying multiple sops files in different file formats:
```nix
{
imports = [ <sops-nix/modules/sops> ];
# The default sops file used for all secrets can be controlled using `sops.defaultSopsFile`
sops.defaultSopsFile = ./secrets.yaml;
# If you use something different from YAML, you can also specify it here:
#sops.defaultSopsFormat = "yaml";
sops.secrets.github_token = {
# The sops file can be also overwritten per secret...
sopsFile = ./other-secrets.json;
# ... as well as the format
format = "json";
};
}
```
### YAML
Open a new file with sops ending in `.yaml`:
```console
$ sops secrets.yaml
```
Then, put in the following content:
```yaml
github_token: 4a6c73f74928a9c4c4bc47379256b72e598e2bd3
ssh_key: |
-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
QyNTUxOQAAACDENhLwQI4v/Ecv65iCMZ7aZAL+Sdc0Cqyjkd012XwJzQAAAJht4at6beGr
egAAAAtzc2gtZWQyNTUxOQAAACDENhLwQI4v/Ecv65iCMZ7aZAL+Sdc0Cqyjkd012XwJzQ
AAAEBizgX7v+VMZeiCtWRjpl95dxqBWUkbrPsUSYF3DGV0rsQ2EvBAji/8Ry/rmIIxntpk
Av5J1zQKrKOR3TXZfAnNAAAAE2pvZXJnQHR1cmluZ21hY2hpbmUBAg==
-----END OPENSSH PRIVATE KEY-----
```
You can include it like this in your `configuration.nix`:
```nix
{
sops.defaultSopsFile = ./secrets.yaml;
# YAML is the default
#sops.defaultSopsFormat = "yaml";
sops.secrets.github_token = {
format = "yaml";
# can be also set per secret
sopsFile = ./secrets.yaml;
};
}
```
### JSON
Open a new file with sops ending in `.json`:
```console
$ sops secrets.json
```
Then, put in the following content:
``` json
{
"github_token": "4a6c73f74928a9c4c4bc47379256b72e598e2bd3",
"ssh_key": "-----BEGIN OPENSSH PRIVATE KEY-----\\nb3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW\\nQyNTUxOQAAACDENhLwQI4v/Ecv65iCMZ7aZAL+Sdc0Cqyjkd012XwJzQAAAJht4at6beGr\\negAAAAtzc2gtZWQyNTUxOQAAACDENhLwQI4v/Ecv65iCMZ7aZAL+Sdc0Cqyjkd012XwJzQ\\nAAAEBizgX7v+VMZeiCtWRjpl95dxqBWUkbrPsUSYF3DGV0rsQ2EvBAji/8Ry/rmIIxntpk\\nAv5J1zQKrKOR3TXZfAnNAAAAE2pvZXJnQHR1cmluZ21hY2hpbmUBAg==\\n-----END OPENSSH PRIVATE KEY-----\\n"
}
```
You can include it like this in your `configuration.nix`:
```nix
{
sops.defaultSopsFile = ./secrets.json;
# YAML is the default
sops.defaultSopsFormat = "json";
sops.secrets.github_token = {
format = "json";
# can be also set per secret
sopsFile = ./secrets.json;
};
}
```
### Binary
This format allows to encrypt an arbitrary binary format that can't be put into
JSON/YAML files. Unlike the other two formats, for binary files, one file corresponds to one secret.
To encrypt an binary file use the following command:
``` console
$ sops -e /etc/krb5/krb5.keytab > krb5.keytab
# an example of what this might result in:
$ head krb5.keytab
{
"data": "ENC[AES256_GCM,data:bIsPHrjrl9wxvKMcQzaAbS3RXCI2h8spw2Ee+KYUTsuousUBU6OMIdyY0wqrX3eh/1BUtl8H9EZciCTW29JfEJKfi3ackGufBH+0wp6vLg7r,iv:TlKiOmQUeH3+NEdDUMImg1XuXg/Tv9L6TmPQrraPlCQ=,tag:dVeVvRM567NszsXKK9pZvg==,type:str]",
"sops": {
"kms": null,
"gcp_kms": null,
"azure_kv": null,
"lastmodified": "2020-07-06T06:21:06Z",
"mac": "ENC[AES256_GCM,data:ISjUzaw/5mNiwypmUrOk2DAZnlkbnhURHmTTYA3705NmRsSyUh1PyQvCuwglmaHscwl4GrsnIz4rglvwx1zYa+UUwanR0+VeBqntHwzSNiWhh7qMAQwdUXmdCNiOyeGy6jcSDsXUeQmyIWH6yibr7hhzoQFkZEB7Wbvcw6Sossk=,iv:UilxNvfHN6WkEvfY8ZIJCWijSSpLk7fqSCWh6n8+7lk=,tag:HUTgyL01qfVTCNWCTBfqXw==,type:str]",
"pgp": [
{
```
It can be decrypted again like this:
``` console
$ sops -d krb5.keytab > /tmp/krb5.keytab
```
This is how it can be included in your `configuration.nix`:
```nix
{
sops.secrets.krb5-keytab = {
format = "binary";
sopsFile = ./krb5.keytab;
};
}
```
## Emit plain file for yaml and json formats
By default, sops-nix extracts a single key from yaml and json files. If you
need the plain file instead of extracting a specific key from the input document,
you can set `key` to an empty string.
For example, the input document `my-config.yaml` likes this:
```yaml
my-secret1: ENC[AES256_GCM,data:tkyQPQODC3g=,iv:yHliT2FJ74EtnLIeeQtGbOoqVZnF0q5HiXYMJxYx6HE=,tag:EW5LV4kG4lcENaN2HIFiow==,type:str]
my-secret2: ENC[AES256_GCM,data:tkyQPQODC3g=,iv:yHliT2FJ74EtnLIeeQtGbOoqVZnF0q5HiXYMJxYx6HE=,tag:EW5LV4kG4lcENaN2HIFiow==,type:str]
sops:
kms: []
gcp_kms: []
azure_kv: []
hc_vault: []
...
```
This is how it can be included in your NixOS module:
```nix
{
sops.secrets.my-config = {
format = "yaml";
sopsFile = ./my-config.yaml;
key = "";
};
}
```
Then, it will be mounted as `/run/secrets/my-config`:
```yaml
my-secret1: hello
my-secret2: hello
```
## Use with home manager
sops-nix also provides a home-manager module.
This module provides a subset of features provided by the system-wide sops-nix since features like the creation of the ramfs and changing the owner of the secrets are not available for non-root users.
The home-manager module requires systemd/user as it runs a service called `sops-nix.service` rather than an activation script.
While the sops-nix _system_ module decrypts secrets to the system non-persistent `/run/secrets`, the _home-manager_ module places them in the users non-persistent `$XDG_RUNTIME_DIR/secrets.d`.
Additionally secrets are symlinked to the users home at `$HOME/.config/sops-nix/secrets` which are referenced for the `.path` value in sops-nix.
This requires that the home-manager option `home.homeDirectory` is set to determine the home-directory on evaluation. It will have to be manually set if home-manager is configured as stand-alone or on non NixOS systems.
Depending on whether you use home-manager system-wide or stand-alone using a home.nix, you have to import it in a different way.
This example shows the `flake` approach from the recommended example [Install: Flakes (current recommendation)](#Flakes (current recommendation))
```nix
{
# NixOS system-wide home-manager configuration
home-manager.sharedModules = [
inputs.sops-nix.homeManagerModules.sops
];
}
```
```nix
{
# Configuration via home.nix
imports = [
inputs.sops-nix.homeManagerModules.sops
];
}
```
This example show the `channel` approach from the example [Install: nix-channel](#nix-channel). All other methods work as well.
```nix
{
# NixOS system-wide home-manager configuration
home-manager.sharedModules = [
<sops-nix/modules/home-manager/sops.nix>
];
}
```
```nix
{
# Configuration via home.nix
imports = [
<sops-nix/modules/home-manager/sops.nix>
];
}
```
The actual sops configuration is in the `sops` namespace in your home.nix (or in the `home-manager.users.<name>` namespace when using home-manager system-wide):
```nix
{
sops = {
age.keyFile = "/home/user/.age-key.txt"; # must have no password!
# It's also possible to use a ssh key, but only when it has no password:
#age.sshKeyPaths = [ "/home/user/path-to-ssh-key" ];
defaultSopsFile = ./secrets.yaml;
secrets.test = {
# sopsFile = ./secrets.yml.enc; # optionally define per-secret files
# %r gets replaced with a runtime directory, use %% to specify a '%'
# sign. Runtime dir is $XDG_RUNTIME_DIR on linux and $(getconf
# DARWIN_USER_TEMP_DIR) on darwin.
path = "%r/test.txt";
};
};
}
```
The secrets are decrypted in a systemd user service called `sops-nix`, so other services needing secrets must order after it:
```nix
{
systemd.user.services.mbsync.Unit.After = [ "sops-nix.service" ];
}
```
### Qubes Split GPG support
If you are using Qubes with the [Split GPG](https://www.qubes-os.org/doc/split-gpg),
then you can configure sops to utilize the `qubes-gpg-client-wrapper` with the `sops.gnupg.qubes-split-gpg` options.
The example above updated looks like this:
```nix
{
sops = {
gnupg.qubes-split-gpg = {
enable = true;
domain = "vault-gpg";
};
defaultSopsFile = ./secrets.yaml;
secrets.test = {
# sopsFile = ./secrets.yml.enc; # optionally define per-secret files
# %r gets replaced with a runtime directory, use %% to specify a '%'
# sign. Runtime dir is $XDG_RUNTIME_DIR on linux and $(getconf
# DARWIN_USER_TEMP_DIR) on darwin.
path = "%r/test.txt";
};
};
}
```
## Use with GPG instead of SSH keys
If you prefer having a separate GPG key, sops-nix also comes with a helper tool, `sops-init-gpg-key`:
```console
$ nix run github:Mic92/sops-nix#sops-init-gpg-key -- --hostname server01 --gpghome /tmp/newkey
# You can use the following command to save it to a file:
$ cat > server01.asc <<EOF
-----BEGIN PGP PUBLIC KEY BLOCK-----
mQENBF8L/iQBCACroEaUfvPBMMorNepNQmideOtNztALejgEJ5wZmxabck+qC1Gb
NWe3tmvChXVHgL7DzodSUfX1PuIjTTeRr2clMXtISPFIsBlRQb4MiErZfsardITM
n4WScg8sTb4nnqEOJiRknwAhBryIjH8kkCXxKlYK67re281dIK4dKBMIolFADlyv
wyHurJ7NPpHxR2WXHcIqXX1DaT6RvGQvZHMpfctob8k/QD4CyV6QwG5IVACQ/tuC
bEUggrkGw+g+XdeieUfWbRsHM4C4pv8BNwA/EYD5d0eKI+rshSPoTT+hcGn8Uh8w
MVQ8PVs6jWMMOAF1JH/stoPr9Yha+TGbMRi5ABEBAAG0GHNlcnZlcjAxIDxyb290
QHNlcnZlcjAxPokBTgQTAQgAOBYhBOTKhnaPF2rrbAFVQVOvjX8UlhOxBQJfC/4k
AhsvBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAAoJEFOvjX8UlhOx1XIH/jUOrSR2
wuoqFiHcqaDPgXmTVJk8QanVkmiP3tk0mz5rRKrDX2eX5GnHqYR4PfpjUYNzedQE
sGyTjl7+DvglWJ2Q8m3yD/9+1agBmeqEVQlKqwL6Sc3bI4WBwHaxwVDo/bNwMs0w
o8ngOs1jPd3LfQdfG/rE1NolpHm4LWqYj0D2zEGqozLXVBx2wiuwmm6OKX4U4EHR
UwKax+VZYA+J9oFDN+kOy/yR+bKnOvg5eyOv2ZrK5BKceSBhDTOclMIWTL2cGxcL
jsq4N7fobs4TbwFPxRUi/T9ldXi0LXeGhTl9stImTtj3bL+4Y734TipvB5UvzCDK
CkjjwEvD5MYdGDE=
=uvIf
-----END PGP PUBLIC KEY BLOCK-----
EOF
# fingerprint: E4CA86768F176AEB6C01554153AF8D7F149613B1
```
You can choose between a RSA GPG key (default, like in the example above) or a
Curve25519 based one by adding `--keytype Curve25519` like so:
```console
$ nix run github:Mic92/sops-nix#sops-init-gpg-key -- --hostname server01 --gpghome /tmp/newkey --keytype Curve25519
You can use the following command to save it to a file:
cat > server01.asc <<EOF
-----BEGIN PGP PUBLIC KEY BLOCK-----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=pf3V
-----END PGP PUBLIC KEY BLOCK-----
EOF
fingerprint: 4413684FC623628CEA3E0929AB2F16C6B5EF89EF
F0477297E369CD1D189DD901278D1535AB473B9E
```
In both cases, you must upload the GPG key directory `/tmp/newkey` onto the server.
If you uploaded it to `/var/lib/sops` than your sops configuration will look like this:
```nix
{
# Make sure that `/var/lib/sops` is owned by root and is not world-readable/writable
sops.gnupg.home = "/var/lib/sops";
# disable importing host ssh keys
sops.gnupg.sshKeyPaths = [];
}
```
However be aware that this will also run GnuPG on your server including the
GnuPG daemon. [GnuPG is in general not great software](https://latacora.micro.blog/2019/07/16/the-pgp-problem.html) and might break in
hilarious ways. If you experience problems, you are on your own. If you want a
more stable and predictable solution go with SSH keys or one of the KMS services.
## Share secrets between different users
Secrets can be shared between different users by creating different files
pointing to the same sops key but with different permissions. In the following
example the `drone` secret is exposed as `/run/secrets/drone-server` for
`drone-server` and as `/run/secrets/drone-agent` for `drone-agent`:
```nix
{
sops.secrets.drone-server = {
owner = config.systemd.services.drone-server.serviceConfig.User;
key = "drone";
};
sops.secrets.drone-agent = {
owner = config.systemd.services.drone-agent.serviceConfig.User;
key = "drone";
};
}
```
## Migrate from pass/krops
If you have used [pass](https://www.passwordstore.org) before (e.g. in
[krops](https://github.com/krebs/krops)) than you can use the following one-liner
to convert all your secrets to a YAML structure:
```console
$ for i in *.gpg; do echo "$(basename $i .gpg): |\n$(pass $(dirname $i)/$(basename $i .gpg)| sed 's/^/ /')"; done
```
Copy the output to the editor you have opened with sops.
## Real-world examples
The [nix-community infra](https://github.com/nix-community/infra) makes extensive usage of sops-nix.
Each host has a [secrets.yaml](https://github.com/nix-community/infra/tree/master/hosts/build01) containing secrets for the host.
Also Samuel Leathers explains his personal setup in this [blog article](https://samleathers.com/posts/2022-02-11-my-new-network-and-sops.html).
## Known limitations
### Initrd secrets
sops-nix does not fully support initrd secrets.
This is because `nixos-rebuild switch` installs
the bootloader before running sops-nix's activation hook.
As a workaround, it is possible to run `nixos-rebuild test`
before `nixos-rebuild switch` to provision initrd secrets
before actually using them in the initrd.
In the future, we hope to extend NixOS to allow keys to be
provisioned in the bootloader install phase.
### Using secrets at evaluation time
It is not possible to use secrets at evaluation time of nix code. This is
because sops-nix decrypts secrets only in the activation phase of nixos i.e. in
`nixos-rebuild switch` on the target machine. If you rely on this feature for
some secrets, you should also include solutions that allow secrets to be stored
securely in your version control, e.g.
[git-agecrypt](https://github.com/vlaci/git-agecrypt). These types of solutions
can be used together with sops-nix.
## Templates
If your setup requires embedding secrets within a configuration file, the `template` feature of `sops-nix` provides a seamless way to do this.
Here's how to use it:
1. **Define Your Secret**
Specify the secrets you intend to use. This will be encrypted and managed securely by `sops-nix`.
```nix
{
sops.secrets.your-secret = { };
}
```
2. **Use Templates for Configuration with Secrets**
Create a template for your configuration file and utilize the placeholder where you'd like the secret to be inserted.
During the activation phase, `sops-nix` will substitute the placeholder with the actual secret content.
```nix
{
sops.templates."your-config-with-secrets.toml".content = ''
password = "${config.sops.placeholder.your-secret}"
'';
}
```
You can also define ownership properties for the configuration file:
```nix
{
sops.templates."your-config-with-secrets.toml".owner = "serviceuser";
}
```
3. **Reference the Rendered Configuration in Services**
When defining a service (e.g., using `systemd`), refer to the rendered configuration (with secrets in place) by leveraging the `.path` attribute.
```nix
{
systemd.services.myservice = {
# ... (any other service attributes)
serviceConfig = {
ExecStart = "${pkgs.myservice}/bin/myservice --config ${config.sops.templates."your-config-with-secrets.toml".path}";
User = "serviceuser";
};
};
}
```