Developer(s) | Canonical Group Limited |
---|---|
Repository | |
Written in | Go, C, Shell script, Python, JavaScript, NASL [1] |
Operating system | Linux |
License | GNU GPLv3 (Client & Runtime), proprietary (Backend) [2] |
Website | snapcraft |
Snap is a software packaging and deployment system developed by Canonical for operating systems that use the Linux kernel and the systemd init system. The packages, called snaps, and the tool for using them, snapd, work across a range of Linux distributions [3] and allow upstream software developers to distribute their applications directly to users. Snaps are self-contained applications running in a sandbox with mediated access to the host system. Snap was originally released for cloud applications [4] but was later ported to also work for Internet of Things devices [5] [6] and desktop [7] [8] applications.
Applications in a Snap run in a container with limited access to the host system. Using Interfaces, users can give an application mediated access to additional features of the host such as recording audio, accessing USB devices and recording video. [9] [10] [11] These interfaces mediate regular Linux APIs so that applications can function in the sandbox without needing to be rewritten. Desktop applications can also use the XDG Desktop Portals, a standardized API originally created by the Flatpak project (originally called xdg-app) to give sandboxed desktop applications access to host resources. [12] [13] These portals often provide a better user experience compared to the native Linux APIs because they prompt the user for permission to use resources such as a webcam at the time the application uses them. The downside is that applications and toolkits need to be rewritten in order to use these newer APIs.
The Snap sandbox also supports sharing data and Unix sockets between Snaps. [14] This is often used to share common libraries and application frameworks between Snaps to reduce the size of Snaps by avoiding duplication. [15] [16]
The Snap sandbox heavily relies on the AppArmor Linux Security Module from the upstream Linux kernel. Because only one "major" Linux Security Module (LSM) can be active at the same time, [17] the Snap sandbox is much less secure when another major LSM is enabled. As a result, on distributions such as Fedora which enable SELinux by default, the Snap sandbox is heavily degraded. Although Canonical is working with many other developers and companies to make it possible for multiple LSMs to run at the same time, this solution is still[ when? ] a long time away. [18] [17] [19]
Multiple times a day, snapd checks for available updates of all Snaps and installs them in the background using an atomic operation. Updates can be reverted [20] [21] and use delta encoding to reduce their download size. [22] [23] [24]
Publishers can release and update multiple versions of their software in parallel using channels. Each channel has a specific track and risk, which indicate the version and stability of the software released on that channel. When installing an application, Snap defaults to using the latest/stable
channel, which will automatically update to new major releases of the software when they become available. Publishers can create additional channels to give users the possibility to stick to specific major releases of their software. For example, a 2.0/stable
channel would allow users to stick to the 2.0 version of the software and only get minor updates without the risk of backwards incompatible changes. When the publisher releases a new major version in a new channel, users can manually update to the next version when they choose. [25] [26] [27] [28]
The schedule, frequency and timing of automatic updates can be configured by users. Users can also pause automatic updates for a certain period of time, or indefinitely. [29] [30] [31] Updates are automatically paused on metered connections. [32] [33]
Developer(s) | Canonical Group Limited |
---|---|
Stable release | 8.5.1 [34] / 16 December 2024 |
Repository | github.com/snapcore/snapcraft |
Written in | Python, Shell script, C++, Go, Dart [35] |
Operating system | Linux |
License | GNU General Public License, version 3.0 |
Website | snapcraft |
Snapcraft is a tool for developers to package their programs in the Snap format. [36] It runs on any Linux distribution supported by Snap, macOS [37] and Microsoft Windows. [38] Snapcraft builds the packages in a Virtual Machine using Multipass, [39] in order to ensure the result of a build is the same, regardless of which distribution or operating system it is built on. [40] Snapcraft supports multiple build tools and programming languages, such as Go, Java, JavaScript, Python, C/C++ and Rust. It also allows importing application metadata from multiple sources such as AppStream, git, shell scripts and setup.py
files. [37] [41]
The Snap Store allows developers to publish their snap-packaged applications. [42] All apps uploaded to the Snap Store undergo automatic testing, including a malware scan. However, the scan does not catch all issues. In one case in May 2018, two applications by the same developer were found to contain a cryptocurrency miner which ran in the background during application execution. When this issue was found, Canonical removed the applications from the Snap Store and transferred ownership of the Snaps to a trusted third party which re-published the Snaps without the miner present. [43] [44] [45] Although the Snap sandbox reduces the impact of a malicious app, Canonical recommends users only install Snaps from publishers trusted by the user. [46] [47]
Snaps are self-contained packages that work across a range of Linux distributions. This is unlike traditional Linux package management approaches, which require specifically adapted packages for each Linux distribution. [48] [49]
The snap file format is a single compressed filesystem using the SquashFS format with the extension .snap
. This filesystem contains the application, libraries it depends on, and declarative metadata. This metadata is interpreted by snapd to set up an appropriately shaped secure sandbox for that application. After installation, the snap is mounted by the host operating system and decompressed on the fly when the files are used. [50] [28] Although this has the advantage that snaps use less disk space, it also means some large applications start more slowly. [51] [52]
Snap supports any class of Linux application such as desktop applications, server tools, IoT apps and even system services such as the printer driver stack. [53] [54] To ensure this, Snap relies on systemd for features such as running socket-activated system services in a Snap. [55] This causes Snap to work best only on distributions that can adopt that init system. [56]
Snap initially only supported the all-Snap Ubuntu Core distribution, but in June 2016, it was ported to a wide range of Linux distributions to become a format for universal Linux packages. [57] Snap requires Systemd which is available in most, but not all, Linux distributions. Other Unix-like systems (e.g. FreeBSD) are not supported. [58] ChromeOS does not support Snap directly, only through Linux distributions installed in it that support Snap, such as Gallium OS. [59]
Ubuntu and its official derivatives pre-install Snap by default, as well as other Ubuntu-based distributions such as KDE Neon, and Zorin OS. [60] Solus have currently planned to drop Snap, to reduce the burden of maintaining AppArmor patches needed for strict Snap confinement. [61] Zorin OS have removed Snap as a default package in the Zorin OS 17 release. [62] While other official Ubuntu derivatives such as Kubuntu, Xubuntu, and Ubuntu MATE have also shipped with the competing Flatpak as a complement, they will no longer do so beginning with Ubuntu 23.04, meaning that it must be installed manually by the user. [63]
A number of notable desktop software development companies publish their software in the Snap Store, including Google, [64] JetBrains, [65] KDE, [66] Microsoft (for Linux versions of e.g. .NET Core 3.1, [67] Visual Studio Code, Skype, [68] and PowerShell), Mozilla [69] and Spotify. [70] Snaps are also used in Internet-of-Things environments, ranging from consumer-facing products [71] to enterprise device management gateways [72] and satellite communication networks. [73] [74] Finally, Snap is also used by developers of server applications such as InfluxDB, [75] Kata Containers, [76] Nextcloud [77] and Travis CI. [78]
Snap has received mixed reaction from the developer community. On Snap's promotional site, Heroku praised Snap's auto-update as it fits their fast release schedule well. Microsoft mentions its ease of use and Snap being YAML-based, as well as it being distribution-agnostic. JetBrains says the Snap Store gives their tools more exposure, [79] [ better source needed ] although some users claim launching the tools takes much longer when it's installed from the Snap Store than when it's installed another way. [80] [ unreliable source ]
Others have objected to the closed-source nature of the Snap Store. Clément Lefèbvre (Linux Mint founder and project leader [81] [82] ) has written that Snap is biased and has a conflict of interest. The reasons he cited include it being governed by Canonical and locked to their store, and also that Snap works better on Ubuntu than on other distributions. [83] He later announced that the installing of Snap would be blocked by APT in Linux Mint, [84] [85] although a way to disable this restriction would be documented. [86]
On recent versions of Ubuntu, Canonical has migrated certain packages exclusively to Snap, such as Chromium and Firefox [87] web browsers. [88] [42] The replacement of Firefox led to mixed reception from users due to performance issues with the Snap version, especially on startup. [87]
Ubuntu is a Linux distribution derived from Debian and composed mostly of free and open-source software. Ubuntu is officially released in multiple editions: Desktop, Server, and Core for Internet of things devices and robots. The operating system is developed by the British company Canonical and a community of other developers, under a meritocratic governance model. As of October 2024, the latest interim release is 24.10, with most-recent long-term support release is 24.04.
seccomp is a computer security facility in the Linux kernel. seccomp allows a process to make a one-way transition into a "secure" state where it cannot make any system calls except exit
, sigreturn
, read
and write
to already-open file descriptors. Should it attempt any other system calls, the kernel will either just log the event or terminate the process with SIGKILL or SIGSYS. In this sense, it does not virtualize the system's resources but isolates the process from them entirely.
AppImage is an open-source format for distributing portable software on Linux. It aims to allow the installation of binary software independently of specific Linux distributions, a concept often referred to as upstream packaging. As a result, one AppImage can be installed and run across various GNU/Linux distributions without needing to use different files. It aims to be a format that is self-contained, rootless, and independent of the underlying Linux distribution.
A portable application, sometimes also called standalone software, is a computer program designed to operate without changing other files or requiring other software to be installed. In this way, it can be easily added to, run, and removed from any compatible computer without setup or side-effects.
Ubuntu releases are made semiannually by Canonical Ltd, its developers, using the year and month of the release as a version number. The first Ubuntu release, for example, was Ubuntu 4.10 and was released on 20 October 2004. Consequently, version numbers for future versions are provisional; if the release is delayed until a different month than planned, the version number will change accordingly.
Ubuntu Unity is a Linux distribution based on Ubuntu, using the Unity interface in place of Ubuntu's GNOME Shell. The first release was 20.04 LTS on 7 May 2020. Prior to the initial release it had the working names of Unubuntu and Ubuntu Unity Remix.
AppStream is an agreement between major Linux vendors to create an infrastructure for application installers on Linux and sharing of metadata.
An app store, also called an app marketplace or app catalog, is a type of digital distribution platform for computer software called applications, often in a mobile context. Apps provide a specific set of functions which, by definition, do not include the running of the computer itself. Complex software designed for use on a personal computer, for example, may have a related app designed for use on a mobile device. Today apps are normally designed to run on a specific operating system—such as the contemporary iOS, macOS, Windows, Linux or Android—but in the past mobile carriers had their own portals for apps and related media content.
Linspire is a commercial operating system based on Debian and Ubuntu and currently owned by PC/OpenSystems LLC. It had been owned by Linspire. Inc. from 2001 to 2008, and then by Xandros from 2008 to 2017.
Solus is an independently developed operating system for the x86-64 architecture based on the Linux kernel and a choice of Budgie, GNOME, KDE Plasma or Xfce as the desktop environment. Its package manager, eopkg, is based on the PiSi package management system from Pardus Linux, and it has a semi-rolling release model, with new package updates landing in the stable repository every Friday. The developers of Solus have stated that Solus was intended exclusively for use on personal computers and will not include software that is only useful in enterprise or server environments.
SuperX is a Linux distribution, a computer operating system originally developed in India. SuperX uses a tweaked version of KDE and is aimed towards beginners and casual users. SuperX features a new launcher made in QML that allows users to get a grid view of all icons of the installed applications in the system, the new launcher is called "SuperX App Launcher".
Elementary OS is a Linux distribution based on Ubuntu LTS. It promotes itself as a "thoughtful, capable, and ethical" replacement to macOS and Windows and has a pay-what-you-want model. The operating system, the desktop environment, and accompanying applications are developed and maintained by elementary, Inc.
GNOME Software is a utility for installing applications and updates on Linux. It is part of the GNOME Core Applications, and was introduced in GNOME 3.10.
Flatpak is a utility for software deployment and package management for Linux. It provides a sandbox environment in which users can run application software in (partial) isolation from the rest of the system. Flatpak was known as xdg-app until 2016.
KDE neon is a Linux distribution developed by KDE based on Ubuntu long-term support (LTS) releases, bundled with a set of additional software repositories containing the latest versions of the Plasma 6 desktop environment/framework, Qt 6 toolkit and other compatible KDE software. First announced in June 2016 by Kubuntu founder Jonathan Riddell following his departure from Canonical Ltd., it has been adopted by a steadily growing number of Linux users, regularly appearing in the Top 20 on DistroWatch.com's popularity tables.
Ubuntu is a Debian-based Linux distribution for personal computers, tablets and smartphones, where the Ubuntu Touch edition is used; and also runs network servers, usually with the Ubuntu Server edition, either on physical or virtual servers or with containers, that is with enterprise-class features.
Pop OS is a free and open-source Linux distribution, based on Ubuntu, and featuring a customized GNOME desktop environment known as COSMIC. The distribution is developed by American Linux computer manufacturer System76. Pop!_OS is primarily built to be bundled with the computers built by System76, but can also be downloaded and installed on most computers.
Foliate is a free and open-source program for reading e-books in Linux. In English, foliate is an adjective meaning to be shaped like a leaf, from the Latin foliatus, meaning leafy.
Clear Linux OS is a Linux distribution, developed and maintained on Intel's 01.org open-source platform, and optimized for Intel's microprocessors with an emphasis on performance and security. Its optimizations are also effective on AMD systems. Clear Linux OS follows a rolling release model. Clear Linux OS is not intended to be a general-purpose Linux distribution; it is designed to be used by IT professionals for DevOps, AI application development, cloud computing, and containers.