We analyze the features of an immutable OS.
/ photo Unsplash
How did Silverblue come about?
Fedora Silverblue is an immutable desktop operating system. In it, all applications run in isolated containers, and updates are installed atomically.
Previously, the project was called . It was later renamed Silverblue. According to the developers, they considered more than 150 names. Silverblue was chosen simply because there was such a free domain and social media accounts.
Updated system Fedora Workstation as priority build for desktops in Fedora 30. The authors say that in the future Silverblue Fedora workstation.
One of the residents of Hacker News that the concept of Silverblue has become the development of the project . It was promoted in Fedora about ten years ago. Stateless Linux was supposed to make it easier to administer thin and thick clients. In it, too, all configuration files of the system were opened in read-only mode.
What gives "immutability"
The term "immutable operating system" means that the root and user directories are mounted in read-only mode. All mutable data is placed in the /var directory. Developers use the same method ΠΈ . This approach increases the security of the OS and prevents the deletion of system files (for example, by mistake).
One of the residents of Hacker News in the topic thread that once accidentally deleted a number of system files while modifying the Ubuntu Yaru theme. At the same time, he did not have backups due to an error in regex. According to him, an immutable OS would help avoid problems.
The installation of updates is also simplified - for this, it is enough to reboot the system from a new image. Additionally, it becomes possible to quickly switch between several branches (Fedora releases). For example, between the currently developed version of Fedora and repository with upcoming updates.
What are the differences from the classic Fedora
OSTree technology is used to install the base environment (/ and /usr). We can say that this is a "versioning" system -packages. RPM packages are translated into the OSTree repository using rpm-ostree. By installing the package, she restore point to which you can rollback in case of failure.
OSTree also install applications from dnf/yum repositories and repositories not supported by Fedora. To do this, instead of the dnf install command, you need to use rpm-ostree install. The system will generate a new base image of the operating system and replace the installed one with it.
Used as a mechanism for updating applications . It runs them in containers. The Flatpack package only includes application-specific dependencies. All core libraries (like the GNOME and KDE libraries) remain pluggable runtime environments. This approach allows you to reduce the size of packages - to exclude repeating components from them.
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To install applications that are not packaged in Flatpack, you can use . It allows you to create a container with a classic Fedora installer.
Similar Solutions
There are other distributions that do similar things to Silverblue. An example would be from openSUSE. This is not a standalone distribution, but part of the openSUSE Kubic platform for deploying CaaS (Container as a Service).
The system works with Docker containers. Their images are distributed as RPM packages. This installation of command line based applications that are not available in Flatpack format. The host system for running containers is formed on the basis of the official repository .
MicroOS was designed to be deployed in large-scale environments (such as data centers), but is also capable of running on single machines.
An example of another similar development is . It is a Linux distribution based on the Nix package manager. Its main feature is the declarative description of configurations. The administrator does not need to install the system and configure it manually. The state is written in a special file: all packages and authentication settings are indicated there. Further, the package manager automatically brings the OS to the specified state.
This system is actively cloud providers, universities and IT companies.
In any case, Silverblue has a chance to find its niche in the market. Whether it succeeds remains to be seen in the future.
Materials from the First Enterprise IaaS Blog:
Additional reading on HabrΓ©:
Source: habr.com