# About

Clear Linux* OS does things differently. Our software architecture provides a unique and innovative platform for Linux* developers focused on performance and security for compute, server, and the cloud.

- What is Clear Linux OS?

- What Clear Linux OS isn’t?

- Is Clear Linux OS completely Open Source?

- Who is the target audience?

- How does Clear Linux OS address security?

- What’s the thinking around Server vs. Desktop?

- What makes Clear Linux OS different?

- Why create new components rather than modifying existing projects?

- Which Components are used in Clear Linux?

## What is Clear Linux OS?

Clear Linux OS is an open source, rolling-release Linux distribution, optimized for performance and security from the cloud to the Edge. Designed from the ground up, Clear Linux OS provides an industry blueprint on how to incorporate Intel® architecture features for a modern, modular Linux OS. Clear Linux OS is not based on any other Linux distro.

## What Clear Linux OS isn’t?

Clear Linux OS is not intended to be a general-purpose Linux distribution, suitable for novice end-users. While we ship common applications, our purpose isn’t to make an OS for routine desktop tasks and provide immunity from all security threats in all situations. Our unique focus means that what we consider essential use cases, optional use cases, or even unsupported use cases, differs from other Linux distros. See our target audience below.

## Is Clear Linux OS completely Open Source?

Clear Linux OS aims to be completely open source. Our project source code and packages source code are available on GitHub*. When considering projects for inclusion, we check that they are in active development and are well maintained. We have a very strict requirement for not accepting proprietary packages and non-open source components. For example, many Linux distros may not be able to include certain media codecs due to licensing restrictions, but manual installation and third party alternatives are available.

## Who is the target audience?

Clear Linux OS mainly targets professionals in IT, DevOps, Cloud/Container deployments, and AI.

Rather than making a standard Linux distribution, the Clear Linux OS team decided to build a unique Linux distro. Developing a distro in house allows us to experiment and iterate faster, which means we continually optimize performance and deliver security patches, several times per week. Yet our experiments are only valuable if our software architecture gives you the freedom to innovate, too. To improve manageability, Clear Linux OS employs a Stateless design, separating user and system management.

We leverage the pool of knowledge and skills at Intel to drive improvements to Clear Linux OS.

Intel has worked with the Linux community and other distros for many years. Understanding what it takes to integrate features in our own Linux distro helps us collaborate with other distro owners and submit enhancements to upstream. We demonstrate the value of our distro by offering users the same tools we use. For example, mixer, a tool unique to Clear Linux OS, allows users to build custom derivatives and act as their own OSV.

For more details on Clear Linux OS features, visit our Clear Linux guides.

## How does Clear Linux OS address security?

Several security features are designed to work out-of-the-box, yet they’re not intended to be intrusive. We focus on essential use cases and ignore unwanted or unsupported use cases. For example, while Clear Linux OS does not enable antivirus by default, we provide a bundle for it (`clamav`). We leave antivirus configuration to our users. In addition, firewalls are less important if the OS doesn’t expose services to the outside by default. In Clear Linux OS, we enforce this strategy by disabling network services by default - e.g. `mariadb` listens on a UNIX socket; `nginx` won’t listen at all; and other services similarly are restricted from being accessed over the network. This strategy alone makes firewall software much less urgent–there simply isn’t anything that a firewall could easily block.

## What’s the thinking around Server vs. Desktop?

Clear Linux OS focuses on performance for server and cloud use-cases first because many design decisions associated with them are applicable to other use-cases, such as IoT and the desktop client. While our initial focus was on the command line, we realized that many people valued the ease-of-use of a desktop environment. Whereas in the past we tried to accommodate those interested in a desktop version, we were forced to confront clear limits as to how we could meet this need. Clear Linux OS minimizes the customizations and patches in support of the desktop and provides a generic GNOME implementation. Other window managers or desktops are available; however, testing in Clear Linux OS is focused on GNOME.

## What makes Clear Linux OS different?

### Release Cadence

Clear Linux OS updates are based on a rolling release that can occur daily, up to a few times per week. Each release has a unique version number that identifies every component in the OS from kernel, to driver, to tool, to GUI application. Most components are included in entities called bundles.

### Updates

By default, Clear Linux OS automatically checks for updates, ensuring the latest performance and security fixes are installed as soon as they are available. Clear Linux OS stays in lockstep with upstream for current security upgrades and is designed to rapidly deliver security mitigations to customers. swupd is designed to manage updates and bundles.

### Ease of Use

Clear Linux OS makes it easier to manage a number of difficult problems.

- Autoproxy makes it possible for Clear Linux OS tools to operate in some proxy environments without needing to be configured.

- Stateless means that configuration settings are easier to manage and remain untouched when system software is updated.

- swupd simplifies managing software and maintaining compatibility.

### Custom Derivatives

The same tools used to build the Clear Linux OS are available in the OS. These tools can be used to create a custom distribution that continues to benefit from upstream rolling releases.

Figure 1: Creating and managing a Clear Linux* OS version (or derivative)

### Create

To create a custom distribution you need to understand how to use the autospec and mixer tools. Additional training materials are available in the how-to-clear GitHub project to help you get started with Clear Linux OS tools.

### Deploy

We also provide training on how to Deploy at Scale.

### Administrate

Clear Linux OS provides a Telemetrics solution for collecting useful information about a deployment, as well as Debug system capabilities.

## Why create new components rather than modifying existing projects?

One question that’s often asked: “Why did you develop your own solution instead of using <XYZ>?” (e.g. swupd post). We do evaluate existing projects for inclusion in Clear Linux OS, yet there are cases where our unique architecture and components would require too much customization to use off-the-shelf projects. In other situations, we may feel that using a new language to develop the component would give us a performance advantage, ease code development and maintenance, and grow the skills of our engineers on new and upcoming programming languages. And yes, sometimes there are personal biases for and against some projects by the architects and engineers. We tend to move fast, and sometimes it’s easier to live with suboptimal choices until we have the time or incentive to re-architect them properly.

## Which Components are used in Clear Linux?

Component | Enabled in OS/Bundle | Optional
--- | --- | ---
OS Installer | Clear Linux installer |
Bootloader | systemd-boot (UEFI) / syslinux (Legacy) |
Boot Manager | Clear Linux Boot Manager |
Configuration initialization and management | NA | micro-config-drive (minimal cloud-init), Ansible
Software component installer, manager, updater | swupd |
Software bundle generator - | mixer and Clear Linux Distro Factory |
Software package builder | autospec |
Software debugging | NA | clr-debug-info
Unified TLS Trust Store Management | clrtrust |
System and software telemetry | NA | Telemetrics (disabled by default)
File system | EXT4 (default for rootfs), VFAT, EXT2 and EXT3, F2FS |
Disk encryption | NA | LUKS
System /Service manager | systemd |
Display manager | GNOME | `KDE`, `Xfce`, `lightdm`, `sddm` (see Clear Linux store)
Display services (Desktop installed) | X.Org | Wayland compositor
Network services | NetworkManager by default, systemd-networkd See Note below. |
SSH Port scanning blocker | Tallow |
Firewall | NA | iptables and firewalld
Antivirus | NA | ClamAV*
Web browser | Lynx or links for text environments, Firefox* for GUI |
Additional Software | Supplied Bundles | Flatpak, 3rd-party software bundles

Note

The Clear Linux OS OS images targeted for cloud deployments continue to use `systemd-networkd` to manage network connections. In earlier Clear Linux OS, `systemd-networkd` was used to manage Ethernet interfaces and NetworkManager was used for wireless interfaces.

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*Other names and brands may be claimed as the property of others.