171 lines
7.7 KiB
Markdown
171 lines
7.7 KiB
Markdown
## Actors
|
|
|
|
- Maintainers
|
|
|
|
The group developing and maintaining this project.
|
|
We are creating the deployment workflows and service configurations, and curate changes proposed by contributors.
|
|
|
|
- Contributors
|
|
|
|
People with the technical background to engage with our work, and may contribute back, build on top of, remix, or feel inspired by our work to create something better.
|
|
|
|
- Hosting provider
|
|
|
|
They provide and maintain the physical infrastructure, and run the software in this repository, through which operators interact with their deployments.
|
|
Hosting providers are technical administrators for these deployments, ensuring availability and appropriate performance.
|
|
|
|
We target small- to medium-scale hosting providers with 20+ physical machines.
|
|
|
|
- Operator
|
|
|
|
They select the applications they want to run.
|
|
They don't need to own hardware or deal with operations.
|
|
Operators administer their applications in a non-technical fashion, e.g. as moderators.
|
|
They pay the hosting provider for registering a domain name, maintaining physical resources, and monitoring deployments.
|
|
|
|
- User
|
|
|
|
They are individuals using applications run by the operators, and e.g. post content.
|
|
|
|
## Glossary
|
|
|
|
- [Fediverse](https://en.wikipedia.org/wiki/Fediverse)
|
|
|
|
A collection of social networking applications that can communicate with each other using a common protocol.
|
|
|
|
- Application
|
|
|
|
User-facing software (e.g. from Fediverse) configured by operators and used by users.
|
|
|
|
- Configuration
|
|
|
|
A collection of settings for a piece of software.
|
|
|
|
> Example: Configurations are deployed to VMs.
|
|
|
|
- Provision
|
|
|
|
Make a resource, such as a virtual machine, available for use.
|
|
|
|
- Deploy
|
|
|
|
Put software onto computers.
|
|
The software includes technical configuration that links software components.
|
|
|
|
- Migrate
|
|
|
|
Move service configurations and deployments (including user data) from one hosting provider to another.
|
|
|
|
- Runtime backend
|
|
|
|
A type of digital environment one can run operating systems such as NixOS on, e.g. bare-metal, a hypervisor, or a container runtime.
|
|
|
|
- Runtime environment
|
|
|
|
The thing a deployment runs on, an interface against which the deployment is working. See runtime backend.
|
|
|
|
- Runtime configuration
|
|
|
|
A specification for mapping components of a configuration to the runtime environment, e.g. which services to deploy to which virtual machines, or how to access object storage.
|
|
|
|
- [NixOps4](https://nixops.dev)
|
|
|
|
A tool to interact with mutable external resources based on declarations in the [Nix language](https://nix.dev/manual/nix/latest/language/).
|
|
|
|
- Resource
|
|
|
|
A [resource for NixOps4](https://nixops.dev/manual/development/concept/resource.html) is any external entity that can be declared with NixOps4 expressions and manipulated with NixOps4, such as a virtual machine, an active NixOS configuration, a DNS entry, or customer database.
|
|
|
|
- Resource provider
|
|
|
|
A resource provider for NixOps4 is an executable that communicates between a resource and NixOps4 using a standardised protocol, allowing [CRUD operations](https://en.wikipedia.org/wiki/Create,_read,_update_and_delete) on the resources to be performed by NixOps4.
|
|
Refer to the [NixOps4 manual](https://nixops.dev/manual/development/resource-provider/index.html) for details.
|
|
|
|
> Example: We need a resource provider for obtaining deployment secrets from a database.
|
|
|
|
## Technologies used
|
|
|
|
This is an incomplete and evolving list of core components planned to be used in this project.
|
|
It will grow to support more advanced use cases as the framework matures.
|
|
|
|
### Nix and [NixOS](https://nixos.org/)
|
|
|
|
NixOS is a Linux distribution with a [vibrant](https://repology.org/repositories/graphs), [reproducible](https://reproducible.nixos.org/) and [security-conscious](https://tracker.security.nixos.org/) ecosystem.
|
|
As such, we see NixOS as the only viable way to reliably create a reproducible outcome for all the work we create.
|
|
|
|
Considered alternatives include:
|
|
|
|
- containers: do not by themselves offer the needed reproducibility
|
|
|
|
### [Proxmox](https://proxmox.com/)
|
|
|
|
Proxmox is a hypervisor, allowing us to create VMs for our applications while adhering to our goal of preventing lock-in.
|
|
In addition, it has been [packaged for Nix](https://github.com/SaumonNet/proxmox-nixos) as well, simplifying our requirements to users setting up our software.
|
|
|
|
Considered alternatives include:
|
|
|
|
- OpenNebula: seemed less mature
|
|
|
|
### [Garage](https://garagehq.deuxfleurs.fr/)
|
|
|
|
Garage is a distributed object storage service.
|
|
For compatibility with existing clients, it reuses the protocol of Amazon S3.
|
|
|
|
Considered alternatives include:
|
|
|
|
- file storage: less centralized for backups
|
|
|
|
## Architecture
|
|
|
|
At the core of Fediversity lies a NixOS configuration module for a set of selected applications.
|
|
|
|
- We will enable using it with **different run-time environments**, such as a single NixOS machine or a ProxmoX hypervisor.
|
|
- Depending on the targeted run-time environment, deployment may involve [NixOps4](https://nixops.dev) or [OpenTofu](https://opentofu.org/) as an **orchestrator**.
|
|
- We further provide demo front-end for **configuring applications** and configuring **run-time backends**.
|
|
|
|
To ensure reproducibility, all software will be packaged with Nix.
|
|
|
|
To reach our goals, we aim to implement the following interactions between [actors](#actors) (depicted with rounded corners) and system components (see the [glossary](#glossary), depicted with rectangles).
|
|
|
|
|
|
|
|
### Service portability
|
|
|
|
The process of migrating one's applications to a different host encompasses:
|
|
|
|
1. Domain registration: involves a (manual) update of DNS records at the registrar
|
|
1. Deploy applications: using the reproducible configuration module
|
|
1. Copy application data:
|
|
- Run back-up/restore scripts
|
|
- Run application-specific migration scripts, to e.g. reconfigure connections/URLs
|
|
|
|
### Data model
|
|
|
|
Whereas the bulk of our configuration logic is covered in the configuration schema, our reference front-end applications will store data.
|
|
The data model design for the configuration front-end needed support the desired functionality is as follows, using the crow's foot notation to denote cardinality:
|
|
|
|
<img src="https://git.fediversity.eu/Fediversity/meta/raw/branch/main/architecture-docs/panel-data-model.svg" alt="" style="max-width:600px;"/>
|
|
|
|
### Host architecture
|
|
|
|
Whereas the core abstraction in Fediversity is a NixOS configuration module, a more full-fledged example architecture of the web host use-case we aim to support as part of our exploitation would be as follows, where virtual machines in question run Fediversity to offer our selected applications:
|
|
|
|
|
|
|
|
## Breakdown of project milestones and key results
|
|
|
|
Whereas details of the implementation may need to be decided as the technical challenges involved become clear, we can already give a higher-level planning of relevant milestones and some of their salient features:
|
|
|
|
- Implement a way to run online services emphasizing user autonomy and data portability
|
|
- Integration tests pass for
|
|
- Setting up a fediversity hosting environment from a declarative configuration
|
|
- Configuring, deploying, and migrating a set of dummy applications
|
|
- Code passes data protection audit
|
|
- Disseminate our results by engaging the open-source community to further expand on work in this direction
|
|
- Present results on at least 3 conferences
|
|
- At least 5 applications compatible with Fediversity thanks to external contributions by 2027-03
|
|
- Exploit our work by enabling reproducible deployments of an initial set of portable applications
|
|
- There are 3 fediverse applications available out of the box:
|
|
- Mastodon
|
|
- PeerTube
|
|
- Pixelfed
|