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Cgroups
cgroups (abbreviated from control groups) is a Linux kernel feature that limits, accounts for, and isolates the resource usage (CPU, memory, disk I/O, etc.) of a collection of processes. Engineers at Google started the work on this feature in 2006 under the name "process containers". In late 2007, the nomenclature changed to "control groups" to avoid confusion caused by multiple meanings of the term "container" in the Linux kernel context, and the control groups functionality was merged into the Linux kernel mainline in kernel version 2.6.24, which was released in January 2008. Since then, developers have added many new features and controllers, such as support for kernfs in 2014, firewalling, and unified hierarchy. cgroup v2 was merged in Linux kernel 4.5 with significant changes to the interface and internal functionality. Versions There are two versions of cgroups. Cgroups was originally written by Paul Menage and Rohit Seth, and merged into the mainline Linux ker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systemd
systemd is a software suite that provides an array of system components for Linux operating systems. The main aim is to unify service configuration and behavior across Linux distributions. Its primary component is a "system and service manager" — an init system used to Bootstrapping, bootstrap user space and manage process (computing), user processes. It also provides replacements for various Daemon (computing), daemons and utilities, including device management, login management, network connection management, and event logging. The name ''systemd'' adheres to the Unix convention of naming daemons by appending the letter ''d''. It also plays on the term "System D", which refers to a person's ability to adapt quickly and improvise to solve problems. Since 2015, the majority of Linux distributions have adopted systemd, having replaced other init systems such as SysV init. It has been praised by developers and users of distributions that adopted it for providing a stable, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System-level Virtualization
OS-level virtualization is an operating system (OS) virtualization paradigm in which the Kernel (operating system), kernel allows the existence of multiple isolated user space and kernel space, user space instances, including containers (LXC, Solaris Containers, AIX Workload_Partitions, WPARs, HP-UX SRP Containers, Docker (software), Docker, Podman), zones (Solaris Containers), virtual private servers (OpenVZ), partitions, virtual environments (VEs), virtual kernels (vkernel, DragonFly BSD), and jails (FreeBSD jail and chroot). Such instances may look like real computers from the point of view of programs running in them. A computer program running on an ordinary operating system can see all resources (connected devices, files and folders, Shared resource, network shares, CPU power, quantifiable hardware capabilities) of that computer. Programs running inside a Containerization (computing), container can only see the container's contents and devices assigned to the container. On U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS-level Virtualization
OS-level virtualization is an operating system (OS) virtualization paradigm in which the kernel allows the existence of multiple isolated user space instances, including containers ( LXC, Solaris Containers, AIX WPARs, HP-UX SRP Containers, Docker, Podman), zones ( Solaris Containers), virtual private servers ( OpenVZ), partitions, virtual environments (VEs), virtual kernels (DragonFly BSD), and jails ( FreeBSD jail and chroot). Such instances may look like real computers from the point of view of programs running in them. A computer program running on an ordinary operating system can see all resources (connected devices, files and folders, network shares, CPU power, quantifiable hardware capabilities) of that computer. Programs running inside a container can only see the container's contents and devices assigned to the container. On Unix-like operating systems, this feature can be seen as an advanced implementation of the standard chroot mechanism, which changes the apparen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernfs (Linux)
In the Linux kernel, kernfs is a set of functions that contain the functionality required for creating the pseudo file systems used internally by various kernel subsystems so that they may use virtual files. For example, sysfs provides a set of virtual files by exporting information about hardware devices and associated device drivers from the kernel's device model to user space. The creation of kernfs resulted from splitting off part of the internal logic used by sysfs. The associated patchset, with Tejun Heo as its main author, was merged into the Linux kernel mainline in kernel version 3.14, which was released on March 30, 2014. Kernfs took the independent and reusable functionality of sysfs so other kernel subsystems can implement their own pseudo file systems more easily and consistently. One of the primary users of kernfs is the pseudo file system used internally by cgroups, whose redesign continued into version 3.15 of the Linux kernel. See also * procfs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Docker (software)
Docker is a set of platform as a service (PaaS) products that use OS-level virtualization to deliver software in packages called ''containers''. The service has both free and premium tiers. The software that hosts the containers is called Docker Engine. It was first released in 2013 and is developed by Docker, Inc. Docker is a tool that is used to automate the deployment of applications in lightweight containers so that applications can work efficiently in different environments in isolation. Background Containers are isolated from one another and bundle their own software, libraries and configuration files; they can communicate with each other through well-defined channels. Because all of the containers share the services of a single operating system kernel, they use fewer resources than virtual machines. Operation Docker can package an application and its dependencies in a virtual container that can run on any Linux, Windows, or macOS computer. This enables the appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lmctfy
lmctfy ("Let Me Contain That For You", pronounced "l-m-c-t-fi") is an implementation of an operating system–level virtualization, which is based on the Linux kernel's cgroups functionality. It provides similar functionality to other container-related Linux tools such as Docker and LXC. Lmctfy is the release of Google's container tools and is free and open-source software subject to the terms of the Apache License The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software ... version 2.0. The maintainers in May 2015 stated their effort to merge their concepts and abstractions into Docker's underlying library libcontainer and thus stopped active development of lmctfy. References External links Presentation slides from initial release announcementProject websiteProject "README" file pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced'' '' – like the letter c'') is a general-purpose programming language. It was created in the 1970s by Dennis Ritchie and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted Central processing unit, CPUs. It has found lasting use in operating systems code (especially in Kernel (operating system), kernels), device drivers, and protocol stacks, but its use in application software has been decreasing. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the most widely used programming langu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux-VServer
Linux-VServer is a virtual private server implementation that was created by adding operating system-level virtualization capabilities to the Linux kernel. It is developed and distributed as open-source software. Details The project was started by Jacques Gélinas. It is now maintained by Herbert Pötzl. It is not related to the Linux Virtual Server project, which implements network Load balancing (computing), load balancing. Linux-VServer is a Operating-system-level virtualization, jail mechanism in that it can be used to securely partition resources on a computer system (such as the file system, CPU time, network addresses and memory) in such a way that process (computing), processes cannot mount a denial-of-service attack on anything outside their partition. Each partition is called a ''security context'', and the virtualized system within it is the ''virtual private server''. A chroot-like utility for descending into security contexts is provided. Booting a virtual priva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Memory
Computer data storage or digital data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but less expensive and larger options further away. Generally, the fast technologies are referred to as "memory", while slower persistent technologies are referred to as "storage". Even the first computer designs, Charles Babbage's Analytical Engine and Percy Ludgate's Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction was extended in the Von Neumann architecture, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Page Cache
In computing, a page cache, sometimes also called disk cache, is a transparent cache for the pages originating from a secondary storage device such as a hard disk drive (HDD) or a solid-state drive (SSD). The operating system keeps a page cache in otherwise unused portions of the main memory (RAM), resulting in quicker access to the contents of cached pages and overall performance improvements. A page cache is implemented in kernels with the paging memory management, and is mostly transparent to applications. Usually, all physical memory not directly allocated to applications is used by the operating system for the page cache. Since the memory would otherwise be idle and is easily reclaimed when applications request it, there is generally no associated performance penalty and the operating system might even report such memory as "free" or "available". When compared to main memory, hard disk drive read/writes are slow and random accesses require expensive disk seeks; as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
File Descriptor
In Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a process-unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket. File descriptors typically have non-negative integer values, with negative values being reserved to indicate "no value" or error conditions. File descriptors are a part of the POSIX API. Each Unix process (except perhaps daemons) should have three standard POSIX file descriptors, corresponding to the three standard streams: Overview In the traditional implementation of Unix, file descriptors index into a per-process maintained by the kernel, that in turn indexes into a system-wide table of files opened by all processes, called the . This table records the ''mode'' with which the file (or other resource) has been opened: for reading, writing, appending, and possibly other modes. It also indexes into a third table called the inode table that describes the ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux Kernel And Daemons With Exclusive Access
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution (distro), which includes the kernel and supporting system software and libraries—most of which are provided by third parties—to create a complete operating system, designed as a clone of Unix and released under the copyleft GPL license. Thousands of Linux distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian, Fedora Linux, Linux Mint, Arch Linux, and Ubuntu, while commercial distributions include Red Hat Enterprise Linux, SUSE Linux Enterprise, and ChromeOS. Linux distributions are frequently used in server platforms. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses and recommends the name "GNU/Linux" to emphasize the use and import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
