Declix

Declarative Unix (declix) is both:

• a pkl-based configuration format that describes the state of various Unix resources.
• a command line tool that applies the description to a running Linux system.

Declix doesn't try to manage full system configuration but concerns itself only with resources declared. Thus you can use Declix to manage only the part of the system, to take over existing one or live side-by-side with other configuration management systems.

Declix can synchronize system state locally or remotely using ssh. Bash is the only system dependencies required to be present on a target.

Visit docs/tutorial.md for a taste of declix operations.

Features

• Over-ssh remote management with minimum target requirements
• Stateless operations
• Partial system management
• Powerful configuration language

Currently supported resources:

• Groups and Users
• Files (present/missing)
• .deb packages (present/missing)
• apt packages (present/missing)

Requirements

There are two machines invloved in declix operations with different requirements:

• driver machine: this is the machine that has access to the configuration, all the necessary resources and runs declix binary to manage the target machine.
• target machine: the machine that is being managed.

Sometimes driver and target machine could be the same, but that is not very typical.

Driver Requirements

• pkl-cli is installed, and found in PATH under pkl name.

Target Requirements

• ssh+scp access with public key
• passwordless sudo
• bash

To manage certain kinds of resources additional tools must be present on the target:

• Files: sha256sum from coreutils
• Deb packages: dpkg
• Apt packages: dpkg, apt

Many of them come preinstalled on most systems, others could be installed using declix itself.

Dedicated User

It is recommended to have a separate user on the target for all declix operations. It can be created like:

sudo adduser --disabled-password declix
sudo usermod -aG sudo declix
echo "declix ALL=(ALL) NOPASSWD:ALL" | sudo tee /etc/sudoers.d/declix
echo "your_public_key_contents" >> /home/declix/.ssh/authorized_keys

Declix Configuration

Declix configuration is based on the pkl configuration language. It fully defines the schema for each managed resource and ensures that declaration files have no errors and are consistent with the current declix version.

Declix doesn't concern itself with where configuration comes from: it could be written manually, generated by various tools or even downloaded from the internet.