Container Linux#ROCKET

Container Linux provides no package manager as a way for distributing payload applications, requiring instead all applications to run inside their containers. Serving as a single control host, a Container Linux instance uses the underlying operating-system-level virtualization features of the Linux kernel to create and configure multiple containers that perform as isolated Linux systems. That way, resource partitioning between containers is performed through multiple isolated userspace instances, instead of using a hypervisor and providing full-fledged virtual machines. This approach relies on the Linux kernel's cgroups and namespaces functionalities,{{Cite web

| url = https://lwn.net/Articles/256389/

| title = Notes from a container

| date = October 29, 2007 | access-date = July 3, 2016

| author = Jonathan Corbet | publisher = LWN.net

}}{{Cite web

| url = https://lwn.net/Articles/621006/

| title = Control group namespaces

| date = November 19, 2014 | access-date = July 3, 2016

| author = Jake Edge | publisher = LWN.net

}} which together provide abilities to limit, account and isolate resource usage (CPU, memory, disk I/O, etc.) for the collections of userspace processes.{{Cite web

| url = https://coreos.com/using-coreos/containers/

| title = CoreOS documentation: Using Docker with CoreOS

| access-date = June 14, 2015

| website = coreos.com

| archive-url = https://web.archive.org/web/20160804005603/https://coreos.com/using-coreos/containers/

| archive-date = August 4, 2016

}}

Initially, Container Linux exclusively used Docker as a component providing an additional layer of abstraction and interface{{Cite web

| url = http://blog.docker.com/2014/03/docker-0-9-introducing-execution-drivers-and-libcontainer/

| title = Docker 0.9: Introducing execution drivers and libcontainer

| date = March 10, 2014 | access-date = January 20, 2015

| website = docker.com

}} to the operating-system-level virtualization features of the Linux kernel, as well as providing a standardized format for containers that allows applications to run in different environments. In December 2014, CoreOS released and started to support rkt (initially released as Rocket) as an alternative to Docker, providing through it another standardized format of the application-container images, the related definition of the container runtime environment, and a protocol for discovering and retrieving container images.{{Cite web

| url = https://www.linux.com/news/featured-blogs/200-libby-clark/806347-collaboration-summit-keynote-alex-polvi-coreos

| title = CoreOS Co-Founder Alex Polvi Talks Containers, Rocket vs. Docker, and More

| date = January 30, 2015 | access-date = June 14, 2015

| author = Libby Clark | publisher = Linux.com

}}{{Cite web

| url = http://www.informationweek.com/cloud/infrastructure-as-a-service/rocket-containers-how-coreos-plans-to-challenge-docker/d/d-id/1319167

| title = Rocket Containers: How CoreOS Plans To Challenge Docker

| date = February 20, 2015 | access-date = June 14, 2015

| author = Charles Babcock | website = informationweek.com

}}{{Cite web

| url = https://coreos.com/blog/rocket/

| title = CoreOS is building a container runtime, rkt

| date = December 1, 2014 | access-date = June 14, 2015

| author = Alex Polvi | website = coreos.com

}}{{Cite web

| url = https://lwn.net/Articles/631630/

| title = New etcd, appc, and Rocket releases from CoreOS

| date = February 4, 2015 | access-date = June 22, 2015

| author = Josh Berkus | publisher = LWN.net

}} CoreOS provides rkt as an implementation of the so-called app container (appc) specification that describes the required properties of the application container image (ACI). CoreOS created appc and ACI as an independent committee-steered set of specifications{{Cite web

| url = https://lwn.net/Articles/644089/

| title = CoreOS Fest and the world of containers, part 1

| date = May 13, 2015 | access-date = June 22, 2015

| author = Josh Berkus | publisher = LWN.net

}}{{Cite web

| url = https://lwn.net/Articles/624349/

| title = The Rocket containerization system

| date = December 3, 2014 | access-date = June 22, 2015

| author = Nathan Willis | publisher = LWN.net

}} aimed to become part of the vendor- and operating-system-independent Open Container Initiative, or OCI, initially named the Open Container Project (OCP)

containerization standard,

{{cite news

| last1 = McAllister

| first1 = Neil

| title = Docker and chums unveil standards org for software containers

| url = https://www.theregister.co.uk/2015/06/22/open_container_project/

| department = Data Centre

| newspaper = The Register

| publication-date = 2015-06-22

| access-date = 2017-01-19

| quote = Announced at the DockerCon conference in San Francisco on Monday, the Open Container Project (OCP) will maintain and develop a common container runtime and image format based in part on code and specs donated by Docker.

}}

which was announced{{by whom|date=January 2017}} in June 2015.{{cite news

| url = https://techcrunch.com/2015/06/22/docker-coreos-google-microsoft-amazon-and-others-agree-to-develop-common-container-standard/

| title = Docker, CoreOS, Google, Microsoft, Amazon and others come together to develop common container standard

| date = June 22, 2015 | access-date = June 24, 2015

| author = Frederic Lardinois | work = TechCrunch

}}{{Cite web

| url = https://www.opencontainers.org/pressrelease/

| title = Industry Leaders Unite to Create Project for Open Container Standards

| date = June 22, 2015

| access-date = June 24, 2015

| website = opencontainers.org

| archive-url = https://web.archive.org/web/20150813223334/https://www.opencontainers.org/pressrelease/

| archive-date = August 13, 2015

}}{{cite web

| url = https://www.theregister.co.uk/2015/07/22/open_container_status_update/

| title = Open Container Project renames, says standard is just weeks away: Linux Foundation, Docker and friends opt for Open Container Initiative

| date = July 22, 2015 | access-date = January 29, 2016

| author = Neil McAllister | website = The Register

}}

Container Linux uses ebuild scripts from Gentoo Linux for automated compilation of its system components, and uses systemd as its primary init system, with tight integration between systemd and various Container Linux's internal mechanisms.{{Cite web

| url = https://coreos.com/using-coreos/systemd/

| title = CoreOS documentation: Using systemd with CoreOS

| access-date = February 13, 2014

| website = coreos.com

| archive-url = https://web.archive.org/web/20140214143636/https://coreos.com/using-coreos/systemd/

| archive-date = February 14, 2014

}}

Container Linux achieves additional security and reliability of its operating system updates by employing FastPatch as a dual-partition scheme for the read-only part of its installation, meaning that the updates are performed as a whole and installed onto a passive secondary boot partition that becomes active upon a reboot or kexec. This approach avoids possible issues arising from updating only certain parts of the operating system, ensures easy rollbacks to a known-to-be-stable version of the operating system, and allows each boot partition to be signed for additional security.{{Cite web

| url = https://coreos.com/using-coreos/updates/

| title = CoreOS documentation: Updates & patches

| access-date = February 27, 2015

| website = coreos.com

| archive-url = https://web.archive.org/web/20140214150559/https://coreos.com/using-coreos/updates/

| archive-date = February 14, 2014

}} The root partition and its root file system are automatically resized to fill all available disk-space upon reboots; while the root partition provides read-write storage space, the operating system itself is mounted read-only under {{Mono|/usr}}.{{Cite web

| url = http://www.activestate.com/blog/2013/08/alex-polvi-explains-coreos

| title = Alex Polvi Explains CoreOS

| date = August 28, 2013

| access-date = May 7, 2015

| author = Phil Whelan

| website = activestate.com

| archive-url = https://web.archive.org/web/20150224184727/http://www.activestate.com/blog/2013/08/alex-polvi-explains-coreos

| archive-date = February 24, 2015

}}{{Cite web

| url = https://coreos.com/docs/cluster-management/scaling/adding-disk-space/

| title = CoreOS documentation: Adding disk space to your CoreOS machine

| access-date = February 27, 2015

| website = coreos.com

}}{{Cite web

| url = https://coreos.com/blog/new-filesystem-btrfs-cloud-config/

| title = Major Update: btrfs, Docker 0.9, add users, writable /etc, and more!

| date = March 27, 2014 | access-date = February 27, 2015

| author = Alex Polvi | website = coreos.com

}}

To ensure that only a certain part of the cluster reboots at once when the operating system updates are applied, preserving the resources required for running deployed applications, CoreOS provides locksmith as a reboot manager for Container Linux.{{Cite web

| url = http://www.centurylinklabs.com/interviews/simple-introduction-to-coreos-with-ceo-alex-polvi-and-cto-brandon-philips/

| title = Simple Introduction to CoreOS with CEO Alex Polvi and CTO Brandon Philips

| date = June 6, 2014

| access-date = June 22, 2015

| website = centurylinklabs.com

| archive-url = https://web.archive.org/web/20150622162656/http://www.centurylinklabs.com/interviews/simple-introduction-to-coreos-with-ceo-alex-polvi-and-cto-brandon-philips/

| archive-date = June 22, 2015

}} Using locksmith, one can select between different update strategies that are determined by how the reboots are performed as the last step in applying updates; for example, one can configure how many cluster members are allowed to reboot simultaneously. Internally, locksmith operates as the {{Mono|locksmithd}} daemon that runs on cluster members, while the {{Mono|locksmithctl}} command-line utility manages configuration parameters.{{Cite web

| url = https://coreos.com/docs/cluster-management/setup/update-strategies/

| title = CoreOS documentation: Update strategies

| access-date = April 17, 2015

| website = coreos.com

}}{{Cite web

| url = https://github.com/coreos/locksmith/blob/master/README.md

| title = coreos/locksmith: locksmith/README.md at master

| date = February 1, 2015 | access-date = April 17, 2015

| website = github.com

}} Locksmith is written in the Go language and distributed under the terms of the Apache License 2.0.{{Cite web

| url = https://github.com/coreos/locksmith/blob/master/LICENSE

| title = coreos/locksmith: locksmith/LICENSE at master

| date = January 19, 2014 | access-date = April 17, 2015

| website = github.com

}}

The updates distribution system employed by Container Linux is based on Google's open-source Omaha project, which provides a mechanism for rolling out updates and the underlying request–response protocol based on XML.{{Cite web

| url = http://www.nextplatform.com/2015/02/25/coreos-hyperscales-linux-by-making-it-invisible/

| title = CoreOS Hyperscales Linux By Making It Invisible

| date = February 15, 2015 | access-date = June 14, 2015

| author = Timothy Prickett Morgan | website = nextplatform.com

}}{{Cite web

| url = https://code.google.com/p/omaha/

| title = Omaha – software installer and auto-updater for Windows

| access-date = October 11, 2014

| website = code.google.com

}}{{Cite web

| url = http://omaha.googlecode.com/svn/wiki/OmahaOverview.html

| title = Omaha Overview

| date = September 23, 2009

| access-date = October 11, 2014

| website = omaha.googlecode.com

| archive-url = https://web.archive.org/web/20090506062328/http://omaha.googlecode.com/svn/wiki/OmahaOverview.html

| archive-date = May 6, 2009

}} Additionally, CoreOS provides CoreUpdate as a web-based dashboard for the management of cluster-wide updates. Operations available through CoreUpdate include assigning cluster members to different groups that share customized update policies, reviewing cluster-wide breakdowns of Container Linux versions, stopping and restarting updates, and reviewing recorded update logs. CoreUpdate also provides an HTTP-based API that allows its integration into third-party utilities or deployment systems.{{Cite web

| url = https://godoc.org/github.com/coreos/go-omaha/omaha

| title = Package omaha

| date = June 24, 2014 | access-date = July 4, 2014

| website = godoc.org

}}{{Cite web

| url = https://coreos.com/products/coreupdate/

| title = CoreOS documentation: CoreUpdate

| access-date = July 4, 2014

| website = coreos.com

}}

[[File:CoreOS Architecture Diagram.svg|thumb|right|upright=2.2|A high-level illustration of the CoreOS cluster architecture{{Cite web

| url = https://github.com/MarkMoudy/coreos-docker-CI-demo

| title = CoreOS + Docker Development Environment Demo

| date = May 16, 2014 | access-date = April 16, 2015

| author = Mark Moudy | website = github.com

}}]]

Container Linux provides etcd, a daemon that runs across all computers in a cluster and provides a dynamic configuration registry, allowing various configuration data to be easily and reliably shared between the cluster members. Since the key–value data stored within {{Mono|etcd}} is automatically distributed and replicated with automated master election and consensus establishment using the Raft algorithm, all changes in stored data are reflected across the entire cluster, while the achieved redundancy prevents failures of single cluster members from causing data loss.{{Cite web

| url = https://lwn.net/Articles/617452/

| title = Etcd and fleet

| date = October 22, 2014 | access-date = June 22, 2015

| author = Jonathan Corbet | publisher = LWN.net

}} Beside the configuration management, {{Mono|etcd}} also provides service discovery by allowing deployed applications to announce themselves and the services they offer. Communication with {{Mono|etcd}} is performed through an exposed REST-based API, which internally uses JSON on top of HTTP; the API may be used directly (through {{Mono|curl}} or {{Mono|wget}}, for example), or indirectly through {{Mono|etcdctl}}, which is a specialized command-line utility also supplied by CoreOS.{{Cite web

| url = https://coreos.com/using-coreos/etcd/

| title = CoreOS documentation: Using etcd with CoreOS

| access-date = February 13, 2014

| website = coreos.com

}}{{Cite web

| url = https://coreos.com/docs/cluster-management/setup/getting-started-with-etcd/

| title = CoreOS documentation: Getting started with etcd

| access-date = February 13, 2014

| website = coreos.com

}}{{Cite web

| url = https://speakerdeck.com/philips/etcd-at-gosf

| title = etcd @ GoSF

| date = January 15, 2014 | access-date = February 13, 2014

| author = Brandon Philips | website = speakerdeck.com

}} etcd is also used in Kubernetes software.

Container Linux also provides the {{Mono|fleet}} cluster manager, which controls Container Linux's separate systemd instances at the cluster level. As of 2017, "fleet" is no longer actively developed and is deprecated in favor of Kubernetes.{{cite web|last1=Wood|first1=Josh|title=Container orchestration: Moving from fleet to Kubernetes|url=https://coreos.com/blog/migrating-from-fleet-to-kubernetes.html|website=coreos..com|publisher=CoreOS}} By using {{Mono|fleetd}}, Container Linux creates a distributed init system that ties together separate systemd instances and a cluster-wide {{Mono|etcd}} deployment; internally, {{Mono|fleetd}} daemon communicates with local {{Mono|systemd}} instances over D-Bus, and with the {{Mono|etcd}} deployment through its exposed API. Using {{Mono|fleetd}} allows the deployment of single or multiple containers cluster-wide, with more advanced options including redundancy, failover, deployment to specific cluster members, dependencies between containers, and grouped deployment of containers. A command-line utility called {{Mono|fleetctl}} is used to configure and monitor this distributed init system;{{Cite web

| url = https://www.digitalocean.com/community/tutorials/how-to-use-fleet-and-fleetctl-to-manage-your-coreos-cluster

| title = How To Use Fleet and Fleetctl to Manage your CoreOS Cluster

| date = September 12, 2014 | access-date = June 22, 2015

| author = Justin Ellingwood | website = digitalocean.com

}} internally, it communicates with the {{Mono|fleetd}} daemon using a JSON-based API on top of HTTP, which may also be used directly. When used locally on a cluster member, {{Mono|fleetctl}} communicates with the local {{Mono|fleetd}} instance over a Unix domain socket; when used from an external host, SSH tunneling is used with authentication provided through public SSH keys.{{Cite web

| url = https://coreos.com/docs/launching-containers/launching/launching-containers-fleet/

| title = CoreOS documentation: Launching containers with fleet

| access-date = April 3, 2014

| website = coreos.com

}}{{Cite web

| url = https://coreos.com/docs/launching-containers/launching/fleet-using-the-client/

| title = CoreOS documentation: Using the client

| access-date = April 3, 2014

| website = coreos.com

}}{{Cite web

| url = https://github.com/coreos/fleet/blob/master/README.md

| title = coreos/fleet: fleet/README.md at master

| date = February 18, 2014 | access-date = April 3, 2014

| website = github.com

}}{{Cite web

| url = https://github.com/coreos/fleet/blob/master/Documentation/deployment-and-configuration.md

| title = coreos/fleet: fleet/Documentation/deployment-and-configuration.md at master (Deploying fleet)

| date = April 14, 2015 | access-date = April 17, 2015

| website = github.com

}}{{Cite web

| url = https://github.com/coreos/fleet/blob/master/Documentation/api-v1.md

| title = coreos/fleet: fleet/Documentation/api-v1.md (fleet API v1)

| date = October 29, 2014 | access-date = April 17, 2015

| website = github.com

}}

All of the above-mentioned daemons and command-line utilities ({{Mono|etcd}}, {{Mono|etcdctl}}, {{Mono|fleetd}} and {{Mono|fleetctl}}) are written in the Go language and distributed under the terms of the Apache License 2.0.

{{Cite web

| url = https://github.com/coreos/fleet/blob/master/LICENSE

| title = coreos/fleet: fleet/LICENSE at master

| date = February 6, 2014 | access-date = April 3, 2014

| website = github.com

}}

When running on dedicated hardware, Container Linux can be either permanently installed on local storage, such as a hard disk drive (HDD) or solid-state drive (SSD),{{Cite web

| url = https://coreos.com/docs/running-coreos/bare-metal/installing-to-disk/

| title = CoreOS documentation: Installing CoreOS to disk

| access-date = February 13, 2014

| website = coreos.com

}} or booted remotely over a network using Preboot Execution Environment (PXE) in general, or iPXE as one of its implementations.{{Cite web

| url = https://coreos.com/docs/running-coreos/bare-metal/booting-with-pxe/

| title = CoreOS documentation: Booting CoreOS via PXE

| access-date = February 13, 2014

| website = coreos.com

}}{{Cite web

| url = https://coreos.com/docs/running-coreos/bare-metal/booting-with-ipxe/

| title = CoreOS documentation: Booting CoreOS via iPXE

| access-date = February 13, 2014

| website = coreos.com

}} CoreOS also supports deployments on various hardware virtualization platforms, including Amazon EC2, DigitalOcean, Google Compute Engine, Microsoft Azure, OpenStack, QEMU/KVM, Vagrant and VMware.{{Cite web

| url = https://coreos.com/blog/digital-ocean-supports-coreos/

| title = CoreOS Image Now Available On DigitalOcean

| date = September 5, 2014 | access-date = September 5, 2014

| author = Alex Crawford | website = coreos.com

}}{{cite web

| url = https://www.theregister.co.uk/2014/05/23/google_loads_coreos_onto_its_cloud/

| title = Google brings futuristic Linux software CoreOS onto its cloud

| date = May 23, 2014 | access-date = May 26, 2014

| author = Jack Clark | website = The Register

}}{{Cite web

| url = https://coreos.com/blog/coreos-available-on-azure/

| title = CoreOS Now Available On Microsoft Azure

| date = October 20, 2014 | access-date = October 22, 2014

| author = Alex Crawford | website = coreos.com

}} Container Linux may also be installed on Citrix XenServer, noting that a "template" for CoreOS exists.

Container Linux can also be deployed through its commercial distribution called Tectonic, which additionally integrates Google's Kubernetes as a cluster management utility. {{As of|2015|04}}, Tectonic is planned to be offered as beta software to select customers.{{cite news

| url = https://www.zdnet.com/article/coreos-is-bringing-googles-kubernetes-to-the-enterprise/

| title = CoreOS is bringing Google's Kubernetes to the enterprise

| date = April 6, 2015 | access-date = April 29, 2015

| author = Steven J. Vaughan-Nichols | work = ZDNet

}}{{cite magazine

| url = https://www.forbes.com/sites/benkepes/2015/04/06/coreos-and-google-make-their-defensive-plays-is-docker-the-victim/

| title = CoreOS And Google Make Their Defensive Plays, Is Docker The Victim?

| date = April 6, 2015 | access-date = April 29, 2015

| author = Ben Kepes | magazine = Forbes

}} Furthermore, CoreOS provides Flannel as a component, implementing an overlay network required primarily for the integration with Kubernetes.{{Cite web

| url = https://coreos.com/blog/introducing-rudder/

| title = Introducing flannel: An etcd-backed overlay network for containers

| date = August 28, 2014 | access-date = June 22, 2015

| author = Eugene Yakubovich | website = coreos.com

}}{{Cite web

| url = http://www.slideshare.net/lorispack/using-coreos-flannel-for-docker-networking

| title = Tutorial on using CoreOS Flannel for Docker

| date = November 2014 | access-date = June 22, 2015

| website = slideshare.net

}}

{{As of|2015|2}}, Container Linux supports only the x86-64 architecture.

{{Clear}}

Following its acquisition of CoreOS, Inc.{{Cite web|url=https://www.cnbc.com/2018/01/30/red-hat-buys-coreos-for-250-mililon.html|title=Red Hat pays $250 million for CoreOS, a start-up that sells Google-developed technology|last=Rosoff|first=Matt|date=2018-01-30|website=CNBC|language=en|access-date=2019-06-06}} in January 2018, Red Hat announced{{Cite web|url=https://coreos.com/blog/fedora-coreos-red-hat-coreos-and-future-container-linux|title=Fedora CoreOS, Red Hat CoreOS, and the future of Container Linux {{!}} CoreOS|website=coreos.com|access-date=2019-06-06}} that it would be merging CoreOS Container Linux with Red Hat's Project Atomic to create a new operating system, Red Hat CoreOS, while aligning the upstream Fedora Project open source community around Fedora CoreOS, combining technologies from both predecessors.

On March 6, 2018, Kinvolk GmbH announced{{Cite web|url=https://kinvolk.io/blog/2018/03/announcing-the-flatcar-linux-project/|title=Announcing the Flatcar Linux project {{!}} Kinvolk|website=kinvolk.io|date=March 6, 2018 |access-date=2019-06-06}} [https://www.flatcar-linux.org/ Flatcar Container Linux], a derivative of CoreOS Container Linux. This tracks the upstream CoreOS alpha, beta, and stable channel releases, with an experimental Edge release channel added in May 2019.{{Cite web|url=https://kinvolk.io/blog/2019/05/introducing-the-flatcar-linux-edge-channel/|title=Introducing the Flatcar Linux Edge Channel {{!}} Kinvolk|website=kinvolk.io|date=May 15, 2019 |access-date=2019-06-06}}

LWN.net reviewed CoreOS in 2014:[http://lwn.net/Articles/593928/ CoreOS: A different kind of Linux distribution [LWN.net]]

{{quote|For those who are putting together large, distributed systems—web applications being a prime example—CoreOS would appear to have a lot of interesting functionality. It should allow applications of that type to grow and shrink as needed with demand, as well as provide a stable platform where upgrades are not a constant headache. For "massive server deployments", CoreOS, or something with many of the same characteristics, looks like the future.}}

{{Portal|Free and open-source software|Linux}}

• Application virtualization{{snd}} software technology that encapsulates application software from the operating system on which it is executed
• Comparison of application virtualization software{{snd}} various portable and scripting language virtual machines
• Comparison of platform virtualization software{{snd}} various emulators and hypervisors, which emulate the whole physical computers
• LXC (Linux Containers){{snd}} an environment for running multiple isolated Linux systems (containers) on a single Linux control host
• Operating-system-level virtualization implementations{{snd}} based on operating system kernel's support for multiple isolated userspace instances
• Software as a service (SaaS){{snd}} a software licensing and delivery model that hosts the software centrally and licenses it on a subscription basis
• Virtualization{{snd}} a general concept of providing virtual versions of computer hardware platforms, operating systems, storage devices, etc.

{{Reflist|30em}}

{{Commons category|CoreOS}}

• Official {{Official website|https://coreos.com/|CoreOS}} and GitHub source code repositories: {{GitHub|coreos|CoreOS|link=hidden}}, {{GitHub|coreos/etcd|etcd|link=hidden}}, {{GitHub|coreos/fleet|fleet|link=hidden}}, {{GitHub|coreos/rkt|rkt|link=hidden}} and {{GitHub|coreos/coreos-overlay|CoreOS-overlay|link=hidden}}
• {{DistroWatch|CoreOS|name=CoreOS}}
• [http://www.sebastien-han.fr/blog/2013/09/03/first-glimpse-at-coreos/ First glimpse at CoreOS], September 3, 2013, by Sébastien Han
• [https://www.zdnet.com/article/coreos-linux-for-the-cloud-and-the-datacenter/ CoreOS: Linux for the cloud and the datacenter], ZDNet, July 2, 2014, by Steven J. Vaughan-Nichols
• [https://www.infoworld.com/article/2692889/coreos-an-existential-threat-to-linux-vendors.html What's CoreOS? An existential threat to Linux vendors], InfoWorld, October 9, 2014, by Matt Asay
• [https://www.thecloudcast.net/2015/03/the-cloudcast-180-understanding-coreos.html Understanding CoreOS distributed architecture], March 4, 2015, a talk to Alex Polvi by Aaron Delp and Brian Gracely
• [https://github.com/coreos/fleet/blob/master/Documentation/architecture.md CoreOS fleet architecture], August 26, 2014, by Brian Waldon et al.
• [https://cloudplatform.googleblog.com/2014/05/official-coreos-images-are-now-available-on-google-compute-engine.html Running CoreOS on Google Compute Engine], May 23, 2014
• [https://www.phoronix.com/scan.php?page=news_item&px=CoreOS-Btrfs-To-EXT4-OverlayFS CoreOS moves from Btrfs to Ext4 + OverlayFS], Phoronix, January 18, 2015, by Michael Larabel
• [https://lwn.net/Articles/646054/ Containers and persistent data], LWN.net, May 28, 2015, by Josh Berkus

{{Linux distributions}}{{Virtualization software}}

{{Linux containers}}

Category:Linux distributions

Category:Enterprise Linux distributions

Category:Linux containerization

Category:Containerization software

Category:Red Hat software

Category:Software using the Apache license

Category:Virtualization software for Linux