krops is a lightweight toolkit to deploy NixOS systems, remotely or locally.
- store your secrets in password store
- build your system remotely
- minimal overhead (it's basically just
nixos-rebuild switch
!) - run from custom nixpkgs branch/checkout/fork
Create a file named krops.nix
(name doesn't matter) with following content:
let
krops = (import <nixpkgs> {}).fetchgit {
url = https://cgit.krebsco.de/krops/;
rev = "v1.17.0";
sha256 = "150jlz0hlb3ngf9a1c9xgcwzz1zz8v2lfgnzw08l3ajlaaai8smd";
};
lib = import "${krops}/lib";
pkgs = import "${krops}/pkgs" {};
source = lib.evalSource [{
nixpkgs.git = {
clean.exclude = ["/.version-suffix"];
ref = "4b4bbce199d3b3a8001ee93495604289b01aaad3";
url = https://github.com/NixOS/nixpkgs;
};
nixos-config.file = toString (pkgs.writeText "nixos-config" ''
{ pkgs, ... }: {
fileSystems."/" = { device = "/dev/sda1"; };
boot.loader.systemd-boot.enable = true;
services.openssh.enable = true;
environment.systemPackages = [ pkgs.git ];
users.users.root.openssh.authorizedKeys.keys = [
"ssh-rsa ADD_YOUR_OWN_PUBLIC_KEY_HERE user@localhost"
];
}
'');
}];
in
pkgs.krops.writeDeploy "deploy" {
source = source;
target = "root@YOUR_IP_ADDRESS_OR_HOST_NAME_HERE";
}
and run $(nix-build --no-out-link krops.nix)
to deploy the target machine.
krops exports some funtions under krops.
namely:
This will make the sources available on the target machine
below /var/src
, and execute nixos-rebuild switch -I /var/src
.
The target
attribute to writeDeploy
can either be a string or an attribute
set, specifying where to make the sources available, as well as where to run
the deployment.
If specified as string, the format could be described as:
[[USER]@]HOST[:PORT][/SOME/PATH]
Portions in square brackets are optional.
If the USER
is the empty string, as in e.g. @somehost
, then the username
will be obtained by ssh from its configuration files.
If the target
attribute is an attribute set, then it can specify the
attributes extraOptions
, host
, path
, port
, sudo
, and user
.
The extraOptions
is a list of strings that get passed to ssh as additional
arguments. The sudo
attribute is a boolean and if set to true, then it's
possible to to deploy to targets that disallow sshing in as root, but allow
(preferably passwordless) sudo.
Example:
pkgs.krops.writeDeploy "deploy" {
source = /* ... */;
target = lib.mkTarget "user@host/path" // {
extraOptions = [
"-oLogLevel=DEBUG"
];
sudo = true;
};
}
For more details about the target
attribute, please check the mkTarget
function in lib/default.nix.
Backup all paths specified in source before syncing new sources.
If set the evaluation and build of the system will be executed on this host.
buildTarget
takes the same arguments as target.
Sources will be synced to both buildTarget
and target
.
Built packages will be uploaded from the buildTarget
to target
directly
This requires the building machine to have ssh access to the target.
To build the system on the same machine, that runs the krops command,
set up a local ssh service and set the build host to localhost.
Use this option if target host architecture is not the same as the build host
architecture as set by buildHost
i.e. deploying to aarch64 from a x86_64
machine. Setting this option will disable building & running nix in the wrong
architecture when running nixos-rebuild
on the deploying machine. It is
required to set nixpkgs.localSystem.system
in the NixOS configuration to the
architecture of the target host. This option is only useful if the build host
also has remote builders that are capable of producing artifacts for the deploy
architecture.
Run nixos-rebuild switch
immediately without building the system
in a dedicated nix build
step.
Create the sentinel file (/var/src/.populate
) before syncing the new source.
Very similiar to writeDeploy, but just builds the system on the target without activating it.
This basically makes the sources available on the target machine
below /var/src
, and executes NIX_PATH=/var/src nix-build -A system '<nixpkgs/nixos>'
.
This can be used to run other commands than nixos-rebuild
or pre/post build hooks.
A function which takes the targetPath as an attribute. Example to activate/deactivate a swapfile before/after build:
pkgs.krops.writeCommand "deploy-with-swap" {
source = source;
target = "root@YOUR_IP_ADDRESS_OR_HOST_NAME_HERE";
command = targetPath: ''
swapon /var/swapfile
nixos-rebuild -I ${targetPath} switch
swapoff /var/swapfile
'';
}
Nix expression to be built at the target machine.
Supported attributes:
text
- Nix expression to be built.
The file source type transfers local files (and folders) to the target
using rsync
.
Supported attributes:
-
path
- absolute path to files that should by transfered -
useChecksum
(optional) - boolean that controls whether file contents should be checked to decide whether a file has changed. This is useful whenpath
points at files with mangled timestamps, e.g. the Nix store. -
filters
(optional) List of filters that should be passed torsync
. Filters are specified as attribute sets with the attributestype
andpattern
. Supported filter types areinclude
andexclude
. Checkout the filter rules section in the rsync manual for further information. -
deleteExcluded
(optional) boolean that controls whether the excluded directories should be deleted if they exist on the target. This is passed to the--delete-excluded
option of rsync. Defaults totrue
.
Git sources that will be fetched on the target machine.
Supported attributes:
-
url
- URL of the Git repository that should be fetched. -
ref
- Branch / tag / commit that should be fetched. -
clean.exclude
- List of patterns that should be excluded from Git cleaning. -
shallow
(optional) boolean that controls whether only the requested commit ref. should be fetched instead of the whole history, to save disk space and bandwith. Defaults tofalse
.
The pass source type transfers contents from a local password store to the target machine.
Supported attributes:
-
dir
- absolute path to the password store. -
name
- sub-directory in the password store.
Executes a local command, capture its stdout, and send that as a file to the target machine.
Supported attributes:
command
- The (shell) command to run.
Symlink to create at the target, relative to the target directory. This can be used to reference files in other sources.
Supported attributes:
target
- Content of the symlink. This is typically a relative path.
Comments, questions, pull-requests, etc. are very welcome, and can be directed at:
- IRC: #krebs at freenode
- Mail: [email protected]