mirror of
https://github.com/QubesOS/qubes-doc.git
synced 2024-12-25 23:39:37 -05:00
Merge branch 'qvm-template' of https://github.com/WillyPillow/qubes-doc
This commit is contained in:
Andrew David Wong
commit
f4177b4554
245
developer/system/template-manager.md
Normal file
245
developer/system/template-manager.md
Normal file
@ -0,0 +1,245 @@
|
|||||||
|
---
|
||||||
|
layout: doc
|
||||||
|
title: Template Manager
|
||||||
|
permalink: /doc/template-manager/
|
||||||
|
---
|
||||||
|
|
||||||
|
# Template Manager
|
||||||
|
|
||||||
|
This document discusses the designs and technical details of `qvm-template`, a soon-to-be template manager application currently in development for Qubes OS.
|
||||||
|
The goals of the project is to design a new mechanism for TemplateVM distribution and a unified tool for template management.
|
||||||
|
|
||||||
|
## Motivation
|
||||||
|
|
||||||
|
This project was originally proposed in the 2020 Google Summer of Code program.
|
||||||
|
|
||||||
|
Previously, TemplateVMs were distributed by RPM packages and managed by `yum`/`dnf`.
|
||||||
|
However, tracking inherently dynamic VM images with a package manager suited for static files creates some challenges.
|
||||||
|
For example, users may accidentally update the images, overriding local changes ([#996], [#1647]).
|
||||||
|
(Or in the case of [#2061], want to specifically override the changes.)
|
||||||
|
Other operations that work well on normal VMs are also somewhat inconsistent on RPM-managed templates.
|
||||||
|
This includes actions such as renaming ([#839]), removal ([#5509]) and backup/restore ([#1385], [#1453], [discussion thread 1], [discussion thread 2]).
|
||||||
|
In turn, this creates inconveniences and confusion for users ([#1403], [#4518]).
|
||||||
|
|
||||||
|
Also, the usage of RPM packages meant that installing a template results in arbitrary code execution, which is not ideal.
|
||||||
|
|
||||||
|
Besides distribution, users may also wish to have an integrated template management application ([#2062], [#2064], [#2534], [#3040]), as opposed to the situation where multiple programs are required for different purposes, e.g., `qubes-dom0-update`, `dnf`, `qvm-remove`, `qubes-manager`.
|
||||||
|
|
||||||
|
To tackle these issues, `qvm-template` is created.
|
||||||
|
It strives to provide not only a better mechanism for handling template installation but also a consistent user-facing interface to deal with template management.
|
||||||
|
|
||||||
|
[#996]: https://github.com/QubesOS/qubes-issues/issues/996
|
||||||
|
[#1647]: https://github.com/QubesOS/qubes-issues/issues/1647
|
||||||
|
[#2061]: https://github.com/QubesOS/qubes-issues/issues/2061
|
||||||
|
[#839]: https://github.com/QubesOS/qubes-issues/issues/839
|
||||||
|
[#5509]: https://github.com/QubesOS/qubes-issues/issues/5509
|
||||||
|
[#1385]: https://github.com/QubesOS/qubes-issues/issues/1385
|
||||||
|
[#1453]: https://github.com/QubesOS/qubes-issues/issues/1453
|
||||||
|
[#1403]: https://github.com/QubesOS/qubes-issues/issues/1403
|
||||||
|
[#4518]: https://github.com/QubesOS/qubes-issues/issues/4518
|
||||||
|
[#2062]: https://github.com/QubesOS/qubes-issues/issues/2062
|
||||||
|
[#2064]: https://github.com/QubesOS/qubes-issues/issues/2064
|
||||||
|
[#2534]: https://github.com/QubesOS/qubes-issues/issues/2534
|
||||||
|
[#3040]: https://github.com/QubesOS/qubes-issues/issues/3040
|
||||||
|
[discussion thread 1]: https://groups.google.com/forum/#!topic/qubes-devel/rwc2_miCNNE/discussion
|
||||||
|
[discussion thread 2]: https://groups.google.com/forum/#!topic/qubes-users/uQEUpv4THsY/discussion
|
||||||
|
|
||||||
|
## Features
|
||||||
|
|
||||||
|
- Install/reinstall/downgrade/upgrade templates, either from local packages or remote repositories
|
||||||
|
- Ability to install templates in alternative pools
|
||||||
|
- Possibility for the template package to specify options such as kernel or `virt_mode` used by the resulting template VM
|
||||||
|
- List and show information about local and available templates
|
||||||
|
- Machine-readable output for easy extension
|
||||||
|
- Search for templates
|
||||||
|
- Remove templates
|
||||||
|
- Optionally, VMs based on the template to be removed can be either removed or "disassociated" -- namely, have their templates changed to a "dummy" one.
|
||||||
|
- Show available repositories
|
||||||
|
- Works in both dom0 and management VMs by utilizing the Admin API
|
||||||
|
- Works well with existing tools
|
||||||
|
- Command-line interface with DNF-like usage
|
||||||
|
- A graphical interface also available
|
||||||
|
|
||||||
|
## Package Format
|
||||||
|
|
||||||
|
The RPM package format is still used.
|
||||||
|
However, the contents are manually extracted instead of installing the whole package.
|
||||||
|
This allows us to take advantage of existing tools for things like repository management.
|
||||||
|
We can also avoid the burden of dealing with verification, reducing the risk of issues like [QSB-28].
|
||||||
|
|
||||||
|
The package name should be in the form `qubes-template-${template_name}`.
|
||||||
|
|
||||||
|
The package metadata (summary, description, etc.) should not contain the `|` character to avoid possibly cryptic errors.
|
||||||
|
This is because of its use as an internal separator.
|
||||||
|
Note that as we already consider the repository metadata untrusted, this should not result in security issues.
|
||||||
|
|
||||||
|
The file structure should be quite similar to previous template RPMs.
|
||||||
|
Namely, there should be the following files in the package:
|
||||||
|
|
||||||
|
- `var/lib/qubes/vm-templates/${template_name}/root.img.part.{00,01,...}`
|
||||||
|
- Split tarball of template `root.img`
|
||||||
|
- Note that the file is still split due to tools such as `rpm2cpio` not supporting large files.
|
||||||
|
(Notably, the cpio format does not support files over 4GiB.)
|
||||||
|
- `var/lib/qubes/vm-templates/${template_name}/template.conf`
|
||||||
|
- Stores custom package metadata (as RPM does not support custom attributes).
|
||||||
|
- Uses `KEY=VALUE` format.
|
||||||
|
- Fields (corresponding to [qvm-prefs]/[qvm-features] tags with the same names)
|
||||||
|
- `virt_mode`
|
||||||
|
- Setting this to `pv` requires user confirmation.
|
||||||
|
- Permitted values: `pv`, `pvh`, `hvm`.
|
||||||
|
- `kernel`
|
||||||
|
- Only allowed to be set to "" (without quotes), i.e., "none", for PVGrub.
|
||||||
|
- Network-related flags: (Must be set to IPv4 addresses in the form of `x.x.x.x`.)
|
||||||
|
- `net.fake-ip`
|
||||||
|
- `net.fake-gateway`
|
||||||
|
- `net.fake-netmask`
|
||||||
|
- Boolean flags: (Permitted values are "1" and "0", denoting "true" and "false" respectively.)
|
||||||
|
- `no-monitor-layout`
|
||||||
|
- `pci-e820-host`
|
||||||
|
- `linux-stubdom`
|
||||||
|
- `gui`
|
||||||
|
- `gui-emulated`
|
||||||
|
- `qrexec`
|
||||||
|
- `var/lib/qubes/vm-templates/${template_name}/whitelisted-appmenus.list`
|
||||||
|
- Contains default app menu entries of the template itself.
|
||||||
|
- `var/lib/qubes/vm-templates/${template_name}/vm-whitelisted-appmenus.list`
|
||||||
|
- Contains default app menu entries of VMs based on the template.
|
||||||
|
- `var/lib/qubes/vm-templates/${template_name}/netvm-whitelisted-appmenus.list`
|
||||||
|
- Contains default app menu entries of NetVMs based on the template.
|
||||||
|
- These three files are the same as the current format.
|
||||||
|
- Note that the contents of these files are stored in `qvm-features` upon installation.
|
||||||
|
See the section below for details.
|
||||||
|
|
||||||
|
[QSB-28]: https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-028-2016.txt
|
||||||
|
[qvm-prefs]: https://dev.qubes-os.org/projects/core-admin-client/en/stable/manpages/qvm-prefs.html#common-properties
|
||||||
|
[qvm-features]: https://dev.qubes-os.org/projects/core-admin-client/en/stable/manpages/qvm-features.html#list-of-known-features
|
||||||
|
|
||||||
|
## Metadata Storage
|
||||||
|
|
||||||
|
The template manager needs to keep metadata of installed templates such as versions and origin.
|
||||||
|
This data can be stored via `qvm-features` to keep things consistent when, e.g., `qvm-remove` is used.
|
||||||
|
Besides, backups are also more easily handled this way.
|
||||||
|
|
||||||
|
Also, the fields can serve as an indicator of whether a template is installed by `qvm-template`.
|
||||||
|
|
||||||
|
### Fields
|
||||||
|
|
||||||
|
Most of the fields should be fairly self-explanatory.
|
||||||
|
|
||||||
|
- `template-name`
|
||||||
|
- Note that this field needs to be consistent with the template name to be considered valid.
|
||||||
|
- `template-epoch`
|
||||||
|
- `template-version`
|
||||||
|
- `template-release`
|
||||||
|
- `template-reponame`
|
||||||
|
- `template-buildtime`
|
||||||
|
- `template-installtime`
|
||||||
|
- The times are in UTC, and are of the format `YYYY-MM-DD HH:MM:SS`.
|
||||||
|
- `template-license`
|
||||||
|
- `template-url`
|
||||||
|
- `template-summary`
|
||||||
|
- `template-description`
|
||||||
|
- Note that the newlines in this field are converted to `|` to work better with existing tools like `qvm-features`.
|
||||||
|
- `menu-items`
|
||||||
|
- `default-menu-items`
|
||||||
|
- `netvm-menu-items`
|
||||||
|
- The `*menu-items` entries store the contents of `var/lib/qubes/vm-templates/${template_name}/whitelisted-appmenus.list`, `var/lib/qubes/vm-templates/${template_name}/vm-whitelisted-appmenus.list`, `var/lib/qubes/vm-templates/${template_name}/netvm-whitelisted-appmenus.list` respectively.
|
||||||
|
- Note that newlines are converted to spaces, again for it to work better with existing tools.
|
||||||
|
This should not cause ambiguity as [the FreeDesktop specifications][freedesktop-spec] forbid spaces in .desktop file names.
|
||||||
|
|
||||||
|
[freedesktop-spec]: https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html
|
||||||
|
|
||||||
|
## Repository Management
|
||||||
|
|
||||||
|
For UpdateVMs to access repository configuration, the package [qubes-repo-templates] is created with the following contents:
|
||||||
|
|
||||||
|
- `/etc/qubes/repo-templates/*.repo`: repository configuration
|
||||||
|
- `/etc/qubes/repo-templates/keys`: PGP keys
|
||||||
|
|
||||||
|
As template keys may be less trusted, they are *not* added to the system RPM keychain but instead managed separately.
|
||||||
|
|
||||||
|
[qubes-repo-templates]: https://github.com/WillyPillow/qubes-repo-templates
|
||||||
|
|
||||||
|
## Qrexec Protocol
|
||||||
|
|
||||||
|
Dom0 and management VMs without network access also need to interact with template repositories.
|
||||||
|
The following qrexec calls that list and download templates are thus proposed.
|
||||||
|
|
||||||
|
- `qubes.TemplateSearch`: wraps `dnf repoquery`
|
||||||
|
- `qubes.TemplateDownload`: wraps `dnf download`
|
||||||
|
|
||||||
|
### Input
|
||||||
|
|
||||||
|
Both calls accept the following format from standard input:
|
||||||
|
|
||||||
|
```text
|
||||||
|
arg1
|
||||||
|
arg2
|
||||||
|
...
|
||||||
|
argN
|
||||||
|
package-file-spec
|
||||||
|
---
|
||||||
|
repo config
|
||||||
|
```
|
||||||
|
|
||||||
|
In other words, the input consists of two parts separated by the line `---`.
|
||||||
|
The first part contains some arguments and `package-file-spec` that indicates the pattern to be queried or downloaded.
|
||||||
|
The following arguments are allowed:
|
||||||
|
|
||||||
|
- `--enablerepo=<repoid>`
|
||||||
|
- `--disablerepo=<repoid>`
|
||||||
|
- `--repoid=<repoid>`
|
||||||
|
- `--releasever=<release>`
|
||||||
|
- `--refresh`
|
||||||
|
|
||||||
|
where the usage is identical to that of DNF.
|
||||||
|
|
||||||
|
For the exact definition of `package-file-spec`, refer to the DNF documentation.
|
||||||
|
|
||||||
|
The second part contains the repository configurations in `yum.repos.d` format.
|
||||||
|
|
||||||
|
### Output
|
||||||
|
|
||||||
|
`qubes.TemplateSearch` prints each package in `%{name}|%{epoch}|%{version}|%{release}|%{reponame}|%{downloadsize}|%{buildtime}|%{license}|%{url}|%{summary}|%{description}|` format to standard output, separated by newlines.
|
||||||
|
Note that there is a `|` at the end of the line.
|
||||||
|
This is because `%{description}` may contain newlines, and doing so allows us to split the entries by `|\n`.
|
||||||
|
(As we are using `dnf repoquery --qf`, we are unable to escape the newlines in advance.)
|
||||||
|
|
||||||
|
`qubes.TemplateDownload`, on the other hand, directly outputs the downloaded content to standard output.
|
||||||
|
|
||||||
|
## Machine-readable Output
|
||||||
|
|
||||||
|
The commands `qvm-template list` and `qvm-template info` provide machine-readable output in both pipe(`|`)-separated and JSON format.
|
||||||
|
See the `qvm-template` man page for details.
|
||||||
|
|
||||||
|
## Interactions with Existing Tools
|
||||||
|
|
||||||
|
### `qvm-remove`
|
||||||
|
|
||||||
|
The existing `qvm-remove` tool should behave identically to `qvm-template remove` -- albeit without fancy features like disassociation.
|
||||||
|
This is unlike the previous situation where `qvm-remove` cannot remove RPM-installed templates.
|
||||||
|
|
||||||
|
Notably, the metadata needs no special handling as it is stored in VM features and thus automatically consistent.
|
||||||
|
|
||||||
|
### Renaming / Cloning
|
||||||
|
|
||||||
|
A template is treated as non-manager-installed once renamed or cloned.
|
||||||
|
However, relevant metadata in the VM features is still retained for future extension and to serve as a hint for the user.
|
||||||
|
|
||||||
|
## Further Reading
|
||||||
|
|
||||||
|
Initial Google Summer of Code (2020) project proposal:
|
||||||
|
|
||||||
|
- <https://hackmd.io/aYauztkGR0iOIoh8fJLecw>
|
||||||
|
|
||||||
|
Previous design document:
|
||||||
|
|
||||||
|
- <https://gist.github.com/WillyPillow/b8a643ddbd9235a97bc187e6e44b16e4>
|
||||||
|
|
||||||
|
Discussion threads:
|
||||||
|
|
||||||
|
- <https://groups.google.com/forum/#!topic/qubes-devel/6Zb_WLy3GY4>
|
||||||
|
- <https://groups.google.com/forum/#!topic/qubes-devel/PyJogqT1TUg>
|
||||||
|
- <https://groups.google.com/forum/#!topic/qubes-devel/2XaMP4Us3kg>
|
||||||
|
- <https://groups.google.com/forum/#!topic/qubes-devel/wF_84b1BR0A>
|
||||||
|
- <https://groups.google.com/forum/#!topic/qubes-devel/pYHnihVCBM0>
|
||||||
Loading…
Reference in New Issue
Block a user