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https://github.com/InitKit/InitKit

Neo-InitWare is a modular, cross-platform reimplementation of the systemd init system. It is experimental.
https://github.com/InitKit/InitKit

bsd cloud ecommerce freebsd init init-system javascript js linux manager modular netbsd openbsd posix service service-manager system systemd typescript unix

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Neo-InitWare is a modular, cross-platform reimplementation of the systemd init system. It is experimental.

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README 

        
![InitKit](docs/Logo.png)

=========================



**InitKit** is the standard Unix init system. It is designed for flexibility in

accordance with a special operationalisation of the principles of the Unix Way.

A novel implementation of the *systemd* init system in JavaScript is hosted atop

a lightweight native framework. Relatively high fidelity is maintained to the

semantics of the systemd transaction generator and job engine.



InitKit is not intended at present to be be used in production. The code is

being written in exploratory fashion for now, and refactoring of some components

will be necessary.



Architecture

------------



The InitKit Scheduler Service, the program which implements the majority of

the InitKit system, is implemented in a modular, layered fashion. We will

start with the lowest levels of that service and proceed upwards.



## Portability Layer



This layer sits directly atop the provisions of the host operating system. The

most basic operations on which the event loop depends may be indirected through

this layer.



## Event Loop (EVLOOP)



InitKit is designed with asynchronicity in mind. A Kernel Queues (or

Libkqueue on non-BSD systems) event loop is the centrepiece of this.



## Core Services



This layer is comprised of several modules which integrate with one-another.



### Job Scheduler (JOBSCHED)



Job scheduling is more thoroughly described in the `niw_scheduling(7)` manual

page.



Responsible for scheduling jobs to run at the correct time. Jobs are

state-querying or state-change requests on objects, e.g. "Start OpenSSH".



The Transaction Generator is a major submodule of the Job Scheduler. It prepares

Transactions which contain a set of jobs to be run in pursuit of a particular

goal job, e.g. "Start OpenSSH" or "Stop NetworkManager".

Transactions are generated with respect to the relationships between objects

specified in the Object Graph.



The result of transaction generation is a set of jobs to be run. With respect

to the `before` and `after` ordering directives, a directed acyclic graph is

formed out of all the objects on which a job is present therefor in the

transaction. Transactions containing conflicting jobs, or out of which a DAG

cannot be formed, are rejected; these arise only from improper cyclic ordering

specifications or conflicting requirements between objets.



Jobs are run starting with the leaves of the graph. As jobs complete (either

successfully or not), they are removed from the graph and action taken. If

another job depends on the completed job having succeeded, then that dependent

job will be cancelled. Any newly-uncovered leaves now run. Some event triggers

may also be invoked on completion of a job, usually within the JavaScript layer.

For example, an object may specify an "on-failure" job to run if it fails to

start.



The result of a transaction is the result of its goal job.



### Process Manager (PROCMAN)



Carries out the low-level tasks of OS process management. Processes are observed

and on GNU/Linux and BSD platforms, this extends to tracking processes as they

create subprocesses and exit (Kernel Queues or CGroups can do this.)



Process launch may be hooked by Process Launch Extensions to alter the execution

environment prior to launching an actual subprocess.



### Service Virtual Machines Monitor (SVMMON)



Governs JavaScript virtual machines provided by the QuickJS library. Extensive

integration with the other core services is provided for. A small library of

functionality to integrate with the operating system directly is provided; the

interfaces are mostly similar to those of Node.JS. A WebWorkers-like API

provides for out-of-process modules to run.



### Reference Monitor (REFMON)



This verifies that requests originating outwith the InitKit scheduler service

hold a right to query a particular object. All connections to the InitKit over

the management interface are associated with a set of rights, e.g. to start or

stop a particular object, to query any object's status, or to shut down the

service manager. Any request made over the management interface must be

authorised by the Reference Monitor before the action can be carried out.



### Schedulable Object Graph (OBJGRAPH)



All objects in the system are maintained in an object graph. This graph

maintains a description of each object sufficient for the other core services to

operate with; this includes the state of the object, its interrelations (edges)

with other objects, and where the various data describing the object was sourced

from.



## JavaScript Services



Various higher-level services are written in JavaScript and run in the virtual

machines.



### InitKit Subsystem for Systemd Services (ISSS)



These components implement support for 



#### Systemd Manifest Loader



This component loads legacy systemd unit-files.



#### Delegated Restarter for Services



Implements the supervision semantics of systemd `.service` units.



Licencing

---------



This software is made available under the terms of the 4-Clause BSD Licence. See

[LICENCE.md](LICENCE.md). If you do not wish to use the software under those

terms, you may use it under the terms of the Affero GPL version 3.0 instead.