Difference between revisions of "Leaflet"

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OpenVZ is an a project lightweight virtualization solution built on 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 server, each of which may be rebooted independently.
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== What is OpenVZ? ==
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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).  Using containers imposes only a 1-3% performance penalty compared to running the same processes on the host system.
 
  
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OpenVZ is free software; everyone can use, redistribute and modify it under the terms of the GNU General Public License.
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OpenVZ это проект, объединяющий технологии контейнерной виртуализации для Linux:
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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.
 
  
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== Virtualization and Isolation ==
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'''Virtuozzo kernel''' is a Linux kernel with patches implements OpenVZ kernel functionality.
  
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Each container has its own independent:
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'''Management utilities''' such as vzctl, to manage container life cycle.
  
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* Files - system libraries, applications, /proc and /sys, file locks
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'''Checkpoint/Restore In Userspace''', or CRIU (pronounced kree-oo, IPA: /krɪʊ/, Russian: криу), is a software tool for Linux operating system. Using this tool, you can freeze a running application (or part of it) and checkpoint it to a hard drive as a collection of files. You can then use the files to restore and run the application from the point it was frozen at. The distinctive feature of the CRIU project is that it is mainly implemented in user space. Docker and LXC uses CRIU to be able migrate containers between servers.
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* Processes - each container has its own PID 1 init
 
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* Users and groups - including root with its own UID 0
 
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* Networking - virtualized network devices, IP addresses, per-container routing and iptables rules
 
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* IPC objects - shared memory, semaphores, messages
 
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* Filesystem - FIXME
 
  
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… and more – everything that makes it feel like a dedicated system.
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'''P.Haul''' is the project on top of CRIU implementing live migration usage scenario.
  
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== Resource Management ==
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'''LibCT''' is a containers management library which provides convenient API for frontend programs to rule a container during its whole lifetime.
  
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Kernel shares and limits containers' resources, so no single container can abuse system resources. The four main subsystems are:
 
  
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* cgroups
 
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* 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.
 
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* I/O scheduler. Distributes available I/O bandwidth between containers according to assigned priorities, with detailed statistics of I/O activity.
 
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* 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.
 
  
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== Live Migration and Checkpointing ==
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== 10 years anniversary  - short history of OpenVZ project ==
  
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OpenVZ can freeze/save the complete state of a container into a dump file (a process known as checkpointing), then create a new container from this dump file. This is similar to suspend-to-disk on a notebook, the difference is OpenVZ only checkpoints a single container, not the whole system.
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http://openvz.org/History
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The container can also be restored on a different physical server, allowing live migration which doesn't interrupt existing user sessions.  
 
  
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== User-level Tools ==
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1999
  
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'''prlctl''' is a high-level command line tool to control  containers and virtual machines. It can create, start, stop, delete, and set various parameters, such as IP addresses, CPU limits, disk quotas...
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Nov 1999: SWsoft chief scientist formulated three main components of Linux containers: set of processes with namespace isolation, file system to share code/ram and isolation in resources.
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Typical prlctl commands:
 
  
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# prlctl create 101 --ostemplate centos-7-x86_64 --vmtype=ct
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2000
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# prlctl set 101 --name virtuozzo
 
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# prlctl set virtuozzo --ipadd 10.10.2.2
 
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# prlctl set 101 --userpasswd root:XXXXXX
 
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# prlctl set virtuozzo --diskspace 20G
 
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# prlctl start virtuozzo
 
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# prlctl exec virtuozzo ps ax
 
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# prlctl enter virtuozzo
 
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# prlctl backup virtuozzo
 
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# prlctl list -a
 
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# prlctl stop virtuozzo
 
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# prlctl delete virtuozzo
 
  
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'''prlsrvctl''' - utility for managing Virtuozzo.
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Feb 2000: 5 people started working on the first mockup version of Virtuozzo (namespaces, isolation, vzfs).
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Jul 2000: limited public beta testing: two public servers (Virtuozzo 0.1 and control panels), 5000 VEs during summer
  
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Typical prlsrvctl commands:
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2002
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# prlsrvctl info
 
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# prlsrvctl net list
 
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# prlsrvctl problem-report –send
 
  
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'''pmigrate''' utility allows you to migrate physical servers to virtual machines and containers  on a node running Virtuozzo. For example, to move a physical server to the virtual machine, you can execute the following command:
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Jan 2002: SWsoft (now known as Odin) initially released a product for Linux named Virtuozzo.
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# pmigrate h 192.168.1.130 v localhost/VM
 
  
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'''pstat''' - top-like utility for gathering statistics.
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2005
  
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== Templates ==
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2005: SWsoft created the OpenVZ Project to release the core of Virtuozzo under GNU GPL.
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2005: SWsoft acquired a hosting/development company "Express" with their own containers for FreeBSD (it was later dropped due to small number of clients).
  
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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.
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2006
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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.
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Precreated templates are available for:
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Jan 2006: Rebase to kernel 2.6.15
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Oct 2006: Port to SPARC and PPC
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Nov 2006: Port to 2.6.18 kernel
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Nov 2006: OpenVZ adds live migration capability
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2007
 +
 
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Mar 2007: Port to RHEL5 kernel
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Mar 2007: Port to 2.6.20 kernel
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2008
 +
 
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Apr 2008: Rebase to kernel 2.6.25
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Oct 2008: Port to ARM
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2009
 +
 
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Aug 2009: Parallels company is in Top 10 Linux kernel contributors with their patches for Linux containers. Our contributions to the kernel at that time was PID, IPC, and network namespaces, with the last one being the biggest.
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2011
 +
 
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Jul 2011: Pavel Emelyanov sent initial RFC and code. The idea of CRIU of course came up earlier when we figured we (or anyone else, for that matter) can't possibly merge in-kernel checkpoint/restore. Re-implementing it in userspace looked crazy for everyone including me, and Andrew Morton's and Linus Torvalds' initial reaction was similar ("some crazy russians").
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Sep 2011: Cyrill Gorcunov made first commit to CRIU project
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2012
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Jul 2012: CRIU v0.1 is available.
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Oct 2012: vzctl for upstream Linux kernel is available
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2014
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Dec 2014: Parallels announced merging OpenVZ and Parallels Cloud Server into single common open source codebase.
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2015
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Apr 2015: Source code of RHEL7-based kernel was published and kernel development process become open.
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Jun 2015: Source code of most userspace utilities was published.
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Jul 2015: Published regularly updated yum repository with Virtuozzo RPM packages and installation ISO image.
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Jul 2015: Announced Virtuozzo 7 Technical Preview - Containers
  
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* CentOS
 
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* Debian
 
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* Ubuntu
 
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* etc.
 
  
 
== Frequently Asked Questions ==
 
== Frequently Asked Questions ==
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OpenVZ wiki is your friend. See http://wiki.openvz.org/
 
OpenVZ wiki is your friend. See http://wiki.openvz.org/
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== Use cases ==
 
== Use cases ==
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=== Development and Testing ===
 
=== Development and Testing ===
  
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• Different distros can co-exist  
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* Different distros can co-exist  
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• A container can be created in a minute
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* A container can be created in a minute
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• Can have hundreds of containers  
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* Can have hundreds of containers  
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• Cloning, snapshots, rollbacks  
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* Cloning, snapshots, rollbacks  
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• A container is a sandbox: work/play, no fear  
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* A container is a sandbox: work/play, no fear  
  
 
=== Security ===
 
=== Security ===
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* No need for a lot of hardware
 
* No need for a lot of hardware
  
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== Recently added features ==
 
  
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* Rebased on RHEL 7 kernel
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* vcmmd – Virtuozzo containers memory management daemon
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* Containers CPU binding (cpumask)
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Stay tuned: https://twitter.com/_openvz_
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* PCI device delegation
 
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* NFS mount migration
 
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* Journaled per-container quota
 
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* ext4 safe writeback mode
 

Revision as of 15:21, 30 July 2015

What is OpenVZ?

OpenVZ это проект, объединяющий технологии контейнерной виртуализации для Linux:

Virtuozzo kernel is a Linux kernel with patches implements OpenVZ kernel functionality.

Management utilities such as vzctl, to manage container life cycle.

Checkpoint/Restore In Userspace, or CRIU (pronounced kree-oo, IPA: /krɪʊ/, Russian: криу), is a software tool for Linux operating system. Using this tool, you can freeze a running application (or part of it) and checkpoint it to a hard drive as a collection of files. You can then use the files to restore and run the application from the point it was frozen at. The distinctive feature of the CRIU project is that it is mainly implemented in user space. Docker and LXC uses CRIU to be able migrate containers between servers.

P.Haul is the project on top of CRIU implementing live migration usage scenario.

LibCT is a containers management library which provides convenient API for frontend programs to rule a container during its whole lifetime.


10 years anniversary - short history of OpenVZ project

http://openvz.org/History

1999

Nov 1999: SWsoft chief scientist formulated three main components of Linux containers: set of processes with namespace isolation, file system to share code/ram and isolation in resources.

2000

Feb 2000: 5 people started working on the first mockup version of Virtuozzo (namespaces, isolation, vzfs). Jul 2000: limited public beta testing: two public servers (Virtuozzo 0.1 and control panels), 5000 VEs during summer

2002

Jan 2002: SWsoft (now known as Odin) initially released a product for Linux named Virtuozzo.

2005

2005: SWsoft created the OpenVZ Project to release the core of Virtuozzo under GNU GPL. 2005: SWsoft acquired a hosting/development company "Express" with their own containers for FreeBSD (it was later dropped due to small number of clients).

2006

Jan 2006: Rebase to kernel 2.6.15 Oct 2006: Port to SPARC and PPC Nov 2006: Port to 2.6.18 kernel Nov 2006: OpenVZ adds live migration capability

2007

Mar 2007: Port to RHEL5 kernel Mar 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 company is in Top 10 Linux kernel contributors with their patches for Linux containers. Our contributions to the kernel at that time was PID, IPC, and network namespaces, with the last one being the biggest.

2011

Jul 2011: Pavel Emelyanov sent initial RFC and code. The idea of CRIU of course came up earlier when we figured we (or anyone else, for that matter) can't possibly merge in-kernel checkpoint/restore. Re-implementing it in userspace looked crazy for everyone including me, and Andrew Morton's and Linus Torvalds' initial reaction was similar ("some crazy russians"). Sep 2011: Cyrill Gorcunov made first commit to CRIU project

2012

Jul 2012: CRIU v0.1 is available. Oct 2012: vzctl for upstream Linux kernel is available

2014

Dec 2014: Parallels announced merging OpenVZ and Parallels Cloud Server into single common open source codebase.

2015

Apr 2015: Source code of RHEL7-based kernel was published and kernel development process become open. Jun 2015: Source code of most userspace utilities was published. Jul 2015: Published regularly updated yum repository with Virtuozzo RPM packages and installation ISO image. Jul 2015: Announced Virtuozzo 7 Technical Preview - Containers


Frequently Asked Questions

What is a container (Virtual Environment, Virtual Private Server)?

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

What is a virtual machine?

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.

What are the highlights of OpenVZ technology?

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

How is OpenVZ different from other technologies?

Virtual Machines boot separate kernels on emulated hardware instances. OpenVZ runs all containers under a single Linux kernel. OpenVZ offers much higher density, hosting 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.

What is the relationship between OpenVZ and LXC?

OpenVZ develops new container technology that then goes upstream into the vanilla Linux kernel. OpenVZ has about a 5 year headstart on LXC, but is actively feeding 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 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.

How scalable is OpenVZ?

OpenVZ scales as well as Linux: 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 from taking a tiny fraction to all available resources, and may be adjusted without restarting it.

How does OpenVZ improve efficiency?

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 ones allows better reliability, better peak performance and typically longer lifespan.

How does OpenVZ improve flexibility of services?

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, live migrate your containers to a new one.

What is the performance overhead?

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

Where do I get (or put) more answers?

OpenVZ wiki is your friend. See http://wiki.openvz.org/

Use cases

Server Consolidation

  • Uniform management
  • Easy to upgrade from Virtuozzo OpenVZ edition to commercial Virtuozzo
  • Scalable
  • Fast migration

Development and Testing

  • Different distros can co-exist
  • A container can be created in a minute
  • Can have hundreds of containers
  • Cloning, snapshots, rollbacks
  • A container is a sandbox: work/play, no fear

Security

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

Hosting

  • Isolated users
  • A container is like a real server, just cheaper
  • Much easier to admin

Educational

  • Every student can have root access
  • Different distributions
  • No need for a lot of hardware



Stay tuned: https://twitter.com/_openvz_

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