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OpenVZ is an a project lightweight = Container-based virtualization solution built on for Linux. It creates multiple isolated, secure containers (an improved chroot providing a complete virtual environment) on a single physical server. Each container acts as a separate virtual machine, with its own process IDs, devices, network addresses and routing, and adjustable resource limits. OpenVZ can create hundreds of containers on a single physical serverFast, each of which may be rebooted independently. Because OpenVZ uses a chroot-based mechanism to provide lightweight virtual machines, both the host and guest OS must be Linux (although each container may run a different Linux distribution)secure. Using containers imposes only a 1-3% performance penalty compared to running the same processes on the host systemChoose three.=

OpenVZ == What is free software; everyone can use, redistribute and modify it under the terms of the GNU General Public License.OpenVZ consists of a modified Linux kernel plus user-level tools. The kernel adds a notion of containers, provides virtualization, isolation, resource management, checkpointing, and live migration.? ==

* Files - system libraries'''Management utilities''', applicationssuch as vzctl, /proc and /sys, file locks* Processes - each container has its own PID 1 init* Users and groups - including root with its own UID 0* Networking - virtualized network devices, IP addresses, per-for managing container routing and iptables rules* IPC objects - shared memory, semaphores, messages* Filesystem - FIXMElife cycle.

… *'''Checkpoint/Restore In Userspace''', or CRIU (pronounced kree-oo, IPA: /krɪʊ/, Russian: криу), is a software tool for Linux that enables you to freeze a running application (or a part of it) and checkpoint it to a hard drive as a collection of files. You can then use the files to restore and more – everything run the application from the point it was frozen at. The distinctive feature of the CRIU project is that makes it feel like a dedicated systemis mainly implemented in userspace. Docker and LXC use CRIU for migrating containers between servers.

Kernel shares and limits containers*' resources, so no single ''LibCT''' is a container management library that provides a convenient API for front-end programs for managing the entire container can abuse system resourceslife cycle. The four main subsystems are:

* cgroups * Fair CPU scheduler. Balances CPU time between containers according to the priorities assigned so no container can abuse the CPU. Can be used to provide hard CPU limits and guarantees. * I== 10-year anniversary - a short [http://O scheduleropenvz. Distributes available Iorg/O bandwidth between containers according to assigned priorities, with detailed statistics History history] of I/O activity.* Two-level disk quota. First level is per-container disk quota, second level is the standard UNIX per-user and per-group disk quota inside a container. OpenVZ project ==

OpenVZ can freeze/save the complete state *Nov 1999: SWsoft chief scientist formulates three key components of Linux containers: a container into a dump file (a process known as checkpointing)set of processes with namespace isolation, then create a new container from this dump file. This is similar system to suspend-to-disk on a notebookshare code and RAM, the difference is OpenVZ only checkpoints a single container, not the whole system.The container can also be restored on a different physical server, allowing live migration which doesn't interrupt existing user sessionsand isolation of resources.

'''prlctl''' is a high-level command line tool to control containers and virtual machines. It can create, *Feb 2000: A team of five people startworking on the first mockup version of Virtuozzo (namespaces, stop, deleteisolation, vzfs).*Jul 2000: A limited public beta testing starts on two public servers (Virtuozzo 0.1 and set various parameters, such as IP addresses, CPU limits, disk quotas.control panels).The number of VEs reaches 5000 during summer.Typical prlctl commands:

# prlctl create 101 --ostemplate centos-7-x86_64 --vmtype=ct # prlctl set 101 --name virtuozzo # prlctl set virtuozzo --ipadd 10.10.2.2 # prlctl set 101 --userpasswd root'''2002''':XXXXXX # prlctl set virtuozzo --diskspace 20G # prlctl start virtuozzo # prlctl exec virtuozzo ps ax # prlctl enter virtuozzo # prlctl backup virtuozzo # prlctl list -a # prlctl stop virtuozzo # prlctl delete virtuozzo

'''prlsrvctl''' - utility *Jan 2002: SWsoft (now known as Odin) rolls out the initial release of Virtuozzo for managing VirtuozzoLinux.

Typical prlsrvctl commands'''2005''': # prlsrvctl info # prlsrvctl net list # prlsrvctl problem-report –send

'''pmigrate''' utility allows you *2005: SWsoft creates the OpenVZ Project to migrate physical servers to virtual machines and containers on a node running release the core of Virtuozzounder GNU GPL. For example, *2005: SWsoft acquires a hosting/development company Express with their own containers for FreeBSD (later dropped due to move a physical server to the virtual machine, you can execute the following command: # pmigrate h 192.168.1small number of clients).130 v localhost/VM

'''pstat2006''' - top-like utility for gathering statistics.:

Templates are container images of various Linux distributions used for rapid container deployment. You can use or modify existing templates, or build your own that suits your particular needs.It is easy to create your own template for OpenVZ by installing a consistent set of packages that forms the base of operating system userland. This can be done with the help of utilities such as yum or debootstrap, depending on the distribution.Precreated templates are available for'''2007''':

* CentOSMar 2007: Port to RHEL5 kernel.* DebianMar 2007: Port to 2.6.20 kernel. '''2008''': *Apr 2008: Rebase to kernel 2.6.25.*Oct 2008: Port to ARM. '''2009''': *Aug 2009: Parallels is in Top 10 Linux kernel contributors with their patches for Linux containers. The contributions to the kernel include PID, IPC, and network namespaces, the last one being the biggest. '''2011''': *Jul 2011: Pavel Emelianov sends initial RFC and code. The idea of CRIU came up earlier when OpenVZ team realized that merging in-kernel checkpoint/restore was impossible. Re-implementing it in userspace looked crazy for everyone, Andrew Morton and Linus Torvalds included ("Some crazy russians").*Sep 2011: Cyrill Gorcunov makes the first commit to the CRIU project. '''2012''': *Jul 2012: CRIU v0.1 is available.*Oct 2012: vzctl for upstream Linux kernel is available. '''2014''': *Dec 2014: Parallels announces merging OpenVZ and Parallels Cloud Server into a single common open source codebase. '''2015''': *Apr 2015: The source code of the RHEL7-based kernel is published and kernel development process becomes open.*Jun 2015: The source code of most userspace utilities is published.* UbuntuJul 2015: A yum repository with Virtuozzo RPM packages and installation ISO image is published and regularly updated.* etcJul 2015: Virtuozzo 7 Technical Preview - Containers is announced.

A container (CT) is an isolated entity which performs and executes works exactly like a stand-alone standalone server. Containers can be rebooted independently and have root access, users/groups, IP address(es)addresses, memory, processes, files, applications, system libraries , and configuration files.

Virtual A virtual machine (VM) is an emulation of a particular computer system. Virtual machines operate based on the computer architecture and functions of a real or hypothetical computer, and their implementations may involve specialized hardware, software, or a combination of both.

OpenVZ is a highly scalable virtualization technology for Linux with near-zero overhead, strong isolation and rapid customer provisioning that's is ready for production use right nowout of the box. Deployment of OpenVZ improves efficiency, flexibility , and quality of service in the enterprise environment.

Virtual Machines machines boot separate kernels on emulated hardware instances. OpenVZ runs all containers under a single Linux kernel. OpenVZ offers a much higher density, hosting enabling to host thousands of containers on a single physical server, but can only run Linux in those containers. Virtual machine solutions usually top out at a few dozen instances, but can run different operating systems in each.

OpenVZ develops a new container technology that then goes upstream into the vanilla Linux kernel. OpenVZ has an about a 5 year headstart head start on LXC, but is actively feeding the technology upstream into vanilla containers. Several internal details currently differ (OpenVZ adds new system calls, vanilla uses the cgroups filesystem, new clone flags, and other mechanisms). '''What applications can run inside an OpenVZ container? ''' Applications and services do not have to be aware of OpenVZ, and most install are installed without any modifications: Java, Oracle, DB/2, Weblogic, Websphere , and many other big applications run just fine inside OpenVZ containers. However, direct access to hardware is not available by default; if required it must be provided by the system administrator.

OpenVZ scales as well as Linuxdoes: we've tested 64 CPUs with 128 GB of RAM. It scales down to embedded devices like smart phones or plug computers. A single container can dynamically scale to take from taking a tiny fraction to all available resources, and may that can be adjusted without restarting itrestart.

OpenVZ improves utilization of existing hardware by increasing average load while still providing the ability to handle peak loads. When buying new servers, using a few powerful boxes instead of many little small ones allows better reliability, better peak performance and typically longer lifespan.

Each container is hardware -independent, and can be moved to another OpenVZ-based system over the network in seconds. This eases hardware maintenance (move out all containers and do whatever you need with the box) and improves availability (keep a synchronized copy of your container elsewhere and start it up if primary service fails). When your old box can no longer cope with peak load, you can live migrate your containers to a new one.

Near zero. There is no emulation layer, only security isolation and resource accounting. All checking is done in the kernel without context switching.

* Uniform management .* Easy to upgrade from Virtuozzo OpenVZ edition to the commercial Virtuozzo.* Scalable .* Fast migration .

• * Different distros can co-exist . • * A container can be created in a minute.• Can * A server can have hundreds of containers .• * Cloning, snapshots, rollbacks are available. • * A container is a sandbox: one can work/and play, no without fear .

* Give each app its own isolated container .* Security hole in an app will not affect others .* Dynamic resource management controls runaway processes.

* Isolated users Users are isolated. * A container is like a real server, just cheaper .* Much easier to admin administer. === Education === * Every student can have root access.* Different distributions are supported.* Low hardware requirements.