[Tails-ux] Clone Persistence option in Tails Installer (#704…

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Szerző: sajolida
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Címzett: Tails user experience & user interface design
CC: The Tails public development discussion list
Tárgy: [Tails-ux] Clone Persistence option in Tails Installer (#7049)
Since we keep a summarized roadmap on our website, we've had "Backups"
on it: https://tails.boum.org/contribute/roadmap/.

We've been testing tons of existing backup solutions in Linux but I
couldn't find any GUI that is decent enough. Some aspects of Tails also
make this more challenging as, for example, some possibly important
information in Persistence is not accessible to the `amnesia` Unix user.

So I've updated the blueprint to describe a new feature for Tails
Installer that I called "Clone Persistence". I'm pasting here the
rationale behind it from the blueprint.

I'd like, most of all, opinions from coders on the cost of such a
solution, keeping in mind that it won't solve all possible user scenarios.

So I'm putting tails-dev@ in copy *once*, please keep the discussion on
tails-ux@ after that; and subscribe to it if you're only on tails-dev@
and want to receive all the messages :) It should be free of spam now!


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As a start, let's focus on this user scenario and solve it as good
and cheaply as possible:

**S1: As a Tails user, I want to create another Tails with all my
data so that I can recover from a lost or broken Tails.**

Other user scenarios are possible for backups but I propose to ignore
them for now. For example:

- S2: My house burns down and I loose all my devices.
- S3: I want to cross a border with no data on me.
- S4: I want to recover file that I had some months ago.

As the bare minimum for S1, I need a backup that is:

- **Fresh**. If backups are tedious and slow to make and update, people
will only update them infrequently and won't have fresh backups when
they need it. We should make it as easy as possible to update backups.

Deja Dup is interesting in this regard: as a user, I am notified to
update my backups regularly and backups start automatically and in the
background as soon as I plug my backup device.

- **Offline**. Online backups can be useful in different scenarios (S2
and S3) but they are also slower to restore and more complicated to
design as they depend on the kind of cloud or online storage solution
the user has access to.

Ideally, the backup for S1 should also be:

- **Fast and simple**. As a user, I might be panicking because I think
that seem to have lost all my data and any extra hoop that I will have
to jump through can add to that panic.

- **Full**. The data stored in Persistence but that is not owned by the
`amnesia` user might not be super critical to loose (eg. Wi-Fi
passwords) but providing a full backup that deals with all the data,
independently of its Unix user, goes along with the goal of being
*Fast and simple*.

Clone Persistence in Tails Installer
====================================

Backup scenarios have 3 experiences:

- Creation
- Update
- Recovery

Recovery
--------

In the case of S1, being able to use Tails again with all my data after
my USB stick breaks.

The easiest possible recovery scenario for S1 is to *already* have all
my data in another Tails, my "backup Tails". If I loose my Tails, I can
start using my backup Tails right away.

### Better UX

- To prevent people confusing their current Tails with their backup
Tails, the backup Tails could be aware that it is a backup Tails and
display some warning when first started. Otherwise, changes made on
the backup Tails would be overwritten when the backup is updated.

Creation
--------

The creation experience could be to clone my Tails using *Tails
Installer* and choose to also clone the Persistence.

If the backup USB stick is new, Tails is installed and the Persistence
is copied. If the backup USB stick already has Tails installed, both the
Tails system on it and the backup of my Persistence are updated.

Before the backup Persistence is being created, the user is prompted for
a passphrase.

Update
------

The action of updating the backups regularly (and maybe being reminded
to do so). In the backend it could use rsync to only copy the files that
have changed.

Before the backup Persistence is being updated, the user is prompted for
a passphrase.

Updating also updates the system partition of the backup Tails.

### Better UX

The update experience could be improved, like Deja Dup does, by:

- Displaying automatic reminders

- Starting the update automatically when the backup Tails is plugged in.

### Open questions

- Is it fine to copy the content of the current Persistence while it is
being used?

Discussion
----------

### Pros

- Maybe the fastest and simplest recovery experience possible.

- The creation experience is pretty simple as well: all I need is a USB
stick that is as big as my current Tails and it will fit all my data.
Tails Installer don't have to display more options.

- The same experience can be used to migrate to a bigger or faster USB
stick. ([[!tails_ticket #14624]])

### Cons

- It won't solve any of the other scenarios. Building backup logic into
Tails Installer might also not be a good investment in case we want to
solve the others scenarios later on in the future. For example, the
recovery experiences for each of S2, S3, and S4 would be completely
different.

### Open questions

- How can we handle the preserve permissions and ownership when doing
the backup without having users to set up an administration password
to create or update their backup?

- How much can we organize this code to be easier to possibly extend to
scenarios S2, S3, and S4 in the future?

Future
======

Once we have a solid solution for S1, we might able to reuse some of
it's UX and code to solve scenarios S2, S3, and S4.

They would require:

- Remote storage
- Backup history
- Include and exclude lists

We should keep these in mind while solving S1 and find a sweet spot
between solving S1 and building foundations to support other backups
scenarios in the future.

--
sajolida