What is OpenVZ? Use cases Container-based virtualization for . OpenVZ is a project that combines the following Server Consolidation Security container virtualization technologies for Linux: • Uniform management. • Give each app its own iso- Fast, lightweight, secure. • Easy to upgrade from Vir- lated container. • Virtuozzo kernel, a Linux kernel with patches that im- tuozzo OpenVZ edition to • Security hole in an app Choose three. plements OpenVZ kernel functionality. the commercial Virtuozzo. will not affect others. • Management utilities, such as vzctl, for managing con- • Scalable. • Dynamic resource man- agement controls runa- tainer life cycle. • Fast migration. way processes. • Checkpoint/Restore In Userspace, or CRIU (pronounced Development and Testing kree-oo, IPA: /krɪʊ/, Russian: криу), is a software tool for Hosting • Different distros can co- Linux that enables you to freeze a running application exist. • Users are isolated. (or a part of it) and checkpoint it to a hard drive as a • A container can be cre- • A container is like a real collection of files. You can then use the files to restore ated in a minute. server, just cheaper. and run the application from the point it was frozen at. • A server can have hun- • Much easier to administer. The distinctive feature of the CRIU project is that it is dreds of containers. mainly implemented in userspace. Docker and LXC use Education • Cloning, snapshots, roll- CRIU for migrating containers between servers. backs are available. • Every student can have root access. • Ploop is a disk loopback block device, not unlike loop • A container is a sandbox: but with many features like dynamic resize, snapshots, one can work and play • Different distributions are supported. backups etc. The main idea is to put container filesys- without fear. tem in a file. • Low hardware require- ments. • P.Haul is the project on top of CRIU that implements the live migration usage scenario. Containers can run various Linux distributions: • LibCT is a container management library that provides Supported by Checkpoint and Restore a convenient API for front-end programs for managing In Userspace the entire container life cycle. www.openvz.org www.criu.org What is the relationship between OpenVZ and LXC? OpenVZ develops a new container technology that then goes OpenVZ Decennial upstream into the vanilla Linux kernel. OpenVZ has an about 5 a short history of the OpenVZ project year head start on LXC, but is actively feeding the technology upstream into vanilla containers. Several internal details cur- rently differ (OpenVZ adds new system calls, vanilla uses the 1999 – SWsoft prepared first concept of product cgroups filesystem, new clone flags, and other mechanisms). with container virtualization What applications can run inside an OpenVZ container? 2000 – Limited public beta testing of new product Applications and services do not have to be aware of OpenVZ, and most are installed without any modifications: Java, Oracle, 2002 – SWsoft initially released a product for DB/2, Weblogic, Websphere, and many other big applications Linux named Virtuozzo 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. 2005 – SWsoft created the OpenVZ Project to release the core of Virtuozzo under GNU GPL Frequently Asked Questions How scalable is OpenVZ? OpenVZ scales as well as Linux does: we’ve tested 64 CPUs 2006 – New ports: SPARC and PPC; OpenVZ What is a container (Virtual Environment, Virtual Private Server)? with 128 GB of RAM. It scales down to embedded devices is available in Debian Linux; OpenVZ adds live like smart phones or plug . A single container can A container (CT) is an isolated entity which works exactly like dynamically scale to take from a tiny fraction to all available migration capability a standalone server. Containers can be rebooted independently resources and that can be adjusted without restart. and have root access, users/groups, IP addresses, memory, pro- 2008 – Published templates for Ubuntu 7.10, cesses, files, applications, system libraries, and configuration How does OpenVZ improve efficiency? created OpenVZ port to ARM files. OpenVZ improves utilization of existing hardware by increas- 2009 – company is in Top 10 Linux What is a virtual machine? ing average load while still providing the ability to handle peak loads. When buying new servers, using a few powerful boxes kernel contributors with their patches for Linux A virtual machine (VM) is an emulation of a particular instead of many small ones allows better reliability, better peak system. Virtual machines operate based on the computer archi- containers performance and typically longer lifespan. tecture and functions of a real or hypothetical computer, and their implementations may involve specialized hardware, soft- 2011 – Prepared first implementation of our new How does OpenVZ improve flexibility of services? ware, or a combination of both. project CRIU Each container is hardware-independent and can be moved to What are the highlights of OpenVZ technology? another OpenVZ-based system over network in seconds. This 2012 – First release of CRIU project, vzctl for eases hardware maintenance (move out all containers and do OpenVZ is a highly scalable virtualization technology for Linux upstream Linux kernel is available whatever you need with the box) and improves availability with near-zero overhead, strong isolation and rapid customer (keep a synchronized copy of your container elsewhere and provisioning that is ready for production use out of the box. De- start it up if primary service fails). When your old box can no 2013 – OpenVZ maintenance partnership ployment of OpenVZ improves efficiency, flexibility, and quality longer cope with peak load, you can live migrate your contain- of service in the enterprise environment. 2014 – Parallels decided to merge OpenVZ ers to a new one. How is OpenVZ different from other technologies? and Virtuozzo into single common open source What is the performance overhead? codebase Virtual machines boot separate kernels on emulated hardware Near zero. There is no emulation layer, only security isolation instances. OpenVZ runs all containers under a single Linux and resource accounting. All checking is done in the kernel kernel. OpenVZ offers a much higher density, enabling to host 2015 – Source code of RHEL7-based kernel without context switching. was published and kernel development process thousands of containers on a single physical server, but can only run Linux in those containers. Virtual machine solutions usually become open Where do I get (or put) more answers? top out at a few dozen instances, but can run different operat- ing systems in each. OpenVZ wiki is your friend. See http://wiki.openvz.org/ Full story is here: http://openvz.org/History