proxmox-offline-mirror/docs/introduction.rst

Introduction
============

What is Proxmox Offline Mirror?
-------------------------------

With the Proxmox Offline Mirror tool, you can manage a local apt mirror for all package updates for
Proxmox and Debian projects. From this local apt mirror you can create an external medium, for
example a USB flash drive or a local network share, to update systems which cannot access the
package repositories directly via the internet.  Such systems might be restricted by policies to
access the public internet or are completely air-gapped.  Finally, you can also manage subscriptions
for such restricted hosts.

This tool consists of two binaries:

``proxmox-offline-mirror``
  The mirror tool to create and manage mirrors and media containing repositories

``proxmox-offline-mirror-helper``
  The helper to use the external medium on offline Proxmox VE, Proxmox Mail Gateway or Proxmox
  Backup Server systems as well as managing subscriptions on these systems.

Terminology
-----------

There are three basic entity types available for configuration:

*keys*
  Subscription keys are either for the mirroring system itself, or for the offline systems.

  They are configured with ``proxmox-offline-mirror key ...``

*mirrors*
  A mirror consists of the metadata of an upstream repository and a local path where **snapshots**
  of the upstream repository are stored.

  - configured with ``proxmox-offline-mirror config mirror ...``

  - used with ``proxmox-offline-mirror mirror ...``

*snapshots*
  Point-in-time view of a mirror. Snapshots consist of hardlinks into the underlying storage pool
  to reduce the disk space requirements.

*media*
  A medium consisting of local mirrors and a path where the mirrors are synced to

  - configured with ``proxmox-offline-mirror config medium ...``

  - used with ``proxmox-offline-mirror medium ...``


Technical Overview
------------------

Behind the scenes, one or more `pools` consisting of

- a pool directory containing checksum files (e.g., `sha256/3dc7bc5f82cdcc4ea0f69dd30d5f6bb19e0ccc36f4a79c865eed0e7a370cd5e4`)
- a link directory containing directories and hardlinks to the checksum files inside the pool
  directory

are used to store the repository contents ("snapshots") of repository mirrors in a space-efficient way.

When adding a file, the following steps are done: first the ckecksum file(s) are added, then they
are linked under one or more paths. A garbage collect operation will iterate over all files in the
link directory and remove those, which are not (or no longer) a hardlink to any checksum files. It
will also remove any checksum files which have no hardlinks outside of the pool's checksum file
directories.

A pool directory can be shared by multiple mirrors in order to deduplicate stored files across the
mirror boundary. For example, it is recommended to have a single pool directory (mirror base directory)
for all mirrors of Proxmox repositories.

The default config path is ``/etc/proxmox-offline-mirror.cfg``, but it can be overriden on a per
command basis (for example, to allow operation as a non-root user). Use the ``--config`` CLI option or
the ``PROXMOX_OFFLINE_MIRROR_CONFIG`` environment variable.


.. _get_help:

Getting Help
------------

.. _get_help_enterprise_support:

Enterprise Support
^^^^^^^^^^^^^^^^^^

Users with a `Proxmox Offline Mirror` subscription have access to the `Proxmox Customer Portal
<https://my.proxmox.com>`_ for offline mirroring/key handling related issues, provided the
corresponding offline system has a valid subscription level higher than `Community`. The customer
portal provides support with guaranteed response times from the Proxmox developers.

For more information or for volume discounts, please contact sales@proxmox.com.

Community Support Forum
^^^^^^^^^^^^^^^^^^^^^^^

We always encourage our users to discuss and share their knowledge using the
`Proxmox Community Forum`_. The forum is moderated by the Proxmox support team.
The large user base is spread out all over the world. Needless to say that such
a large forum is a great place to get information.

Mailing Lists
^^^^^^^^^^^^^

Proxmox Offline Mirror is fully open-source and contributions are welcome! The Proxmox VE
development mailing list acts as the primary communication channel for offline mirror developers:

:Mailing list for developers: `PVE Development List`_

Bug Tracker
^^^^^^^^^^^

Proxmox runs a public bug tracker at `<https://bugzilla.proxmox.com>`_. If an
issue appears, file your report there. An issue can be a bug, as well as a
request for a new feature or enhancement. The bug tracker helps to keep track
of the issue and will send a notification once it has been solved.

License
-------

|pom-copyright|

This software is written by Proxmox Server Solutions GmbH <support@proxmox.com>

Proxmox Offline Mirror is free and open source software: you can use it,
redistribute it, and/or modify it under the terms of the GNU Affero General
Public License as published by the Free Software Foundation, either version 3
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but
``WITHOUT ANY WARRANTY``; without even the implied warranty of
``MERCHANTABILITY`` or ``FITNESS FOR A PARTICULAR PURPOSE``.  See the GNU
Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see AGPL3_.