Atomic, declarative, and reproducible secret provisioning for NixOS based on sops.
Secrets are decrypted from sops files during
activation time. The secrets are stored as one secret per file and access-controlled by full declarative configuration of their users, permissions, and groups.
GPG keys or age keys can be used for decryption, and compatibility shims are supported to enable the use of SSH RSA or SSH Ed25519 keys.
Sops also supports cloud key management APIs such as AWS
KMS, GCP KMS, Azure Key Vault and Hashicorp Vault. While not
officially supported by sops-nix yet, these can be controlled using
environment variables that can be passed to sops.
- Compatible with all NixOS deployment frameworks: NixOps, nixos-rebuild, krops, morph, nixus, etc.
- Version-control friendly: Since all files are encrypted they can be directly committed to version control without worry. Diffs of the secrets are readable, and can be shown in cleartext.
- CI friendly: Since sops files can be added to the Nix store without leaking secrets, a machine definition can be built as a whole from a repository, without needing to rely on external secrets or services.
- Home-manager friendly: Provides a home-manager module
- Works well in teams: sops-nix comes with
nix-shellhooks that allows multiple people to quickly import all GPG keys. The cryptography used in sops is designed to be scalable: Secrets are only encrypted once with a master key instead of encrypted per machine/developer key. - Atomic upgrades: New secrets are written to a new directory which replaces the old directory atomically.
- Rollback support: If sops files are added to the Nix store, old secrets can be rolled back. This is optional.
- Fast time-to-deploy: Unlike solutions implemented by NixOps, krops and morph, no extra steps are required to upload secrets.
- A variety of storage formats: Secrets can be stored in YAML, dotenv, INI, JSON or binary.
- Minimizes configuration errors: sops files are checked against the configuration at evaluation time.
There is a configuration.nix example in the deployment step of our usage example.
sops-nix supports two basic ways of encryption, GPG and age.
GPG is based on GnuPG 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 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.
The tool (ssh-to-age) can convert SSH host or user keys in Ed25519
format to age keys.
If you prefer video over the textual description below, you can also checkout this 6min tutorial by @vimjoyer.
1. Install sops-nix
Choose one of the following methods. When using it non-globally with home-manager, refer to Use with home-manager.
If you use experimental nix flakes support:
{
inputs.sops-nix.url = "github:Mic92/sops-nix";
# optional, not necessary for the module
#inputs.sops-nix.inputs.nixpkgs.follows = "nixpkgs";
outputs = { self, nixpkgs, sops-nix }: {
# change `yourhostname` to your actual hostname
nixosConfigurations.yourhostname = nixpkgs.lib.nixosSystem {
# customize to your system
system = "x86_64-linux";
modules = [
./configuration.nix
sops-nix.nixosModules.sops
];
};
};
}niv (recommended if not using flakes)
First add it to niv:
$ niv add Mic92/sops-nixThen add the following to your configuration.nix in the imports list:
{
imports = [ "${(import ./nix/sources.nix).sops-nix}/modules/sops" ];
}Add the following to your configuration.nix:
{
imports = let
# replace this with an actual commit id or tag
commit = "298b235f664f925b433614dc33380f0662adfc3f";
in [
"${builtins.fetchTarball {
url = "https://github.com/Mic92/sops-nix/archive/${commit}.tar.gz";
# replace this with an actual hash
sha256 = "0000000000000000000000000000000000000000000000000000";
}}/modules/sops"
];
}2. Generate a key for yourself
This key will be used for you to edit secrets.
You can generate yourself a key:
# 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-keyOr you can use the ssh-to-pgp tool to get a GPG key from an SSH key:
$ 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,
ssh-to-pgp: failed to parse private ssh key: ssh: this private key is passphrase protectedthen your SSH key is encrypted with your password and you will need to create an unencrypted copy temporarily.
$ 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_rsaHow to find the public key of an `age` key
If you generated an age key, the age public key can be found via age-keygen -y $PATH_TO_KEY:
$ age-keygen -y ~/.config/sops/age/keys.txt
age12zlz6lvcdk6eqaewfylg35w0syh58sm7gh53q5vvn7hd7c6nngyseftjxlOtherwise, you can convert an existing SSH key into an age public key:
$ 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"How to find the GPG fingerprint of a key
Invoke this command and look for your key:
$ gpg --list-secret-keys
/tmp/tmp.JA07D1aVRD/pubring.kbx
-------------------------------
sec rsa2048 1970-01-01 [SCE]
9F89C5F69A10281A835014B09C3DC61F752087EF
uid [ unknown] root <root@localhost>The fingerprint here is 9F89C5F69A10281A835014B09C3DC61F752087EF.
Your age public key or GPG fingerprint can be written to your .sops.yaml in the root of your configuration directory or repository:
# This example uses YAML anchors which allows reuse of multiple keys
# without having to repeat yourself.
# Also see https://github.com/Mic92/dotfiles/blob/master/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_bobNote:
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.
3. Get a public key for your 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:
$ 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'
age1rgffpespcyjn0d8jglk7km9kfrfhdyev6camd3rck6pn8y47ze4sug23v3For 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:
$ 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"
0fd60c8c3b664aceb1796ce02b318df330331003The output of these commands is the identifier for the server's key, which can be added to your .sops.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_bobIf you prefer having a separate GPG key, see Use with GPG instead of SSH keys.
4. Create a sops file
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.
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).
# 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:
$ tree .
.
├── keys
│ ├── hosts
│ │ └── server01.asc
│ └── users
│ └── mic92.ascAfter configuring .sops.yaml, you can open a new file with sops:
$ 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:
# 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: password1An example result when saving this file could be:
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"
5. Deploy
If you derived your server public key from SSH, all you need in your configuration.nix is:
{
imports = [ <sops-nix/modules/sops> ];
# 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:
$ 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}:
$ ls -la /run/secrets
lrwxrwxrwx 16 root 12 Jul 6:23 /run/secrets -> /run/secrets.d/1By 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:
$ 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-secretThe secrets option has further parameter to change secret permission. Consider the following nixos configuration example:
{
# 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;
}This example configures secrets for buildkite, a CI agent; the service needs a token and a SSH private key to function.
{ 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;
}It is possible to restart or reload units when a secret changes or is newly initialized.
This behavior can be configured per-secret:
{
sops.secrets."home-assistant-secrets.yaml" = {
restartUnits = [ "home-assistant.service" ];
# there is also `reloadUnits` which acts like a `reloadTrigger` in a NixOS systemd service
};
}Some services might expect files in certain locations.
Using the path option a symlink to this directory can
be created:
{
sops.secrets."home-assistant-secrets.yaml" = {
owner = "hass";
path = "/var/lib/hass/secrets.yaml";
};
}$ 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.yamlsops-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
$ echo "password" | mkpasswd -s
$y$j9T$WFoiErKnEnMcGq0ruQK4K.$4nJAY3LBeBsZBTYSkdTOejKU6KlDmhnfUV3Ll1K/1b.{ 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, you must set sops.age.keyFile to a keyfile inside your persist directory or it will not exist at boot time.
For example: /nix/persist/var/lib/sops-nix/key.txt
Similarly if ssh host keys are used instead, they also need to be placed inside the persisted storage.
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:
{
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";
};
}Open a new file with sops ending in .yaml:
$ sops secrets.yamlThen, put in the following content:
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:
{
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;
};
}Open a new file with sops ending in .json:
$ sops secrets.jsonThen, put in the following content:
{
"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:
{
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;
};
}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:
$ cp /etc/krb5/krb5.keytab > krb5.keytab
$ sops -e -o 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:
$ sops -d krb5.keytab > /tmp/krb5.keytabThis is how it can be included in your configuration.nix:
{
sops.secrets.krb5-keytab = {
format = "binary";
sopsFile = ./krb5.keytab;
};
}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.
Instead of running as an activation script, sops-nix runs as a systemd user service called sops-nix.service.
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)
{
# NixOS system-wide home-manager configuration
home-manager.sharedModules = [
inputs.sops-nix.homeManagerModules.sops
];
}{
# Configuration via home.nix
imports = [
inputs.sops-nix.homeManagerModules.sops
];
}This example show the channel approach from the example Install: nix-channel. All other methods work as well.
{
# NixOS system-wide home-manager configuration
home-manager.sharedModules = [
<sops-nix/modules/home-manager/sops.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):
{
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:
{
systemd.user.services.mbsync.Unit.After = [ "sops-nix.service" ];
}If you prefer having a separate GPG key, sops-nix also comes with a helper tool, sops-init-gpg-key:
$ 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-----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=uvIf
-----END PGP PUBLIC KEY BLOCK-----
EOF
# fingerprint: E4CA86768F176AEB6C01554153AF8D7F149613B1You can choose between a RSA GPG key (default, like in the example above) or a
Curve25519 based one by adding --keytype Curve25519 like so:
$ 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
F0477297E369CD1D189DD901278D1535AB473B9EIn 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:
{
# 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 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.
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:
{
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";
};
}If you have used pass before (e.g. in krops) than you can use the following one-liner to convert all your secrets to a YAML structure:
$ for i in *.gpg; do echo "$(basename $i .gpg): |\n$(pass $(dirname $i)/$(basename $i .gpg)| sed 's/^/ /')"; doneCopy the output to the editor you have opened with sops.
The nix-community infra makes extensive usage of sops-nix. Each host has a secrets.yaml containing secrets for the host. Also Samuel Leathers explains his personal setup in this blog article.
sops-nix does not fully support initrd secrets.
This is because nixos-rebuild switch installs
the bootloader before running sops-nix's activation hook.
As a workaround, it is possible to run nixos-rebuild test
before nixos-rebuild switch to provision initrd secrets
before actually using them in the initrd.
In the future, we hope to extend NixOS to allow keys to be
provisioned in the bootloader install phase.
It is not possible to use secrets at evaluation time of nix code. This is
because sops-nix decrypts secrets only in the activation phase of nixos i.e. in
nixos-rebuild switch on the target machine. If you rely on this feature for
some secrets, you should also include solutions that allow secrets to be stored
securely in your version control, e.g.
git-agecrypt. These types of solutions
can be used together with sops-nix.
If your setup requires embedding secrets within a configuration file, the template feature of sops-nix provides a seamless way to do this.
Here's how to use it:
-
Define Your Secret
Specify the secrets you intend to use. This will be encrypted and managed securely by
sops-nix.{ sops.secrets.your-secret = { }; }
-
Use Templates for Configuration with Secrets
Create a template for your configuration file and utilize the placeholder where you'd like the secret to be inserted. During the activation phase,
sops-nixwill substitute the placeholder with the actual secret content.{ sops.templates."your-config-with-secrets.toml".content = '' password = "${config.sops.placeholder.your-secret}" ''; }
You can also define ownership properties for the configuration file:
{ sops.templates."your-config-with-secrets.toml".owner = "serviceuser"; }
-
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.pathattribute.{ 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"; }; }; }
- agenix: Similar features as sops-nix but uses age.
- scalpel: Provides a simple template mechanism to inject secrets into configuration files in the nixos activation phase
We are building sops-nix very much as contributors to the community and are committed to keeping it open source.
That said, many of us that are contributing to sops-nix also work for consultancies. If you want to contact one of those for paid-for support setting up sops-nix in your infrastructure you can do so here:
![bors[bot] avatar](https://avatars.githubusercontent.com/in/1847?v=4 "bors[bot]")
![dependabot[bot] avatar](https://avatars.githubusercontent.com/in/29110?v=4 "dependabot[bot]")
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