Difference between revisions of "FAQ"

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{{Virtuozzo}}
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== General ==
 
== General ==
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===== What is a container (Virtual Environment, Virtual Private Server, VPS, VE)? =====
 
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:See [[Container]].
 
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===== What are highlights of OpenVZ technology? =====
 
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In short, OpenVZ is the only highly scalable virtualization technology 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.
 
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===== Who needs OpenVZ? How it can be used? =====
 
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:See [[Use cases]].
 
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===== What applications can run inside an OpenVZ container? =====
 
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Most applications can be installed to a container without any modifications. Oracle, DB/2, Weblogic, Websphere and other big applications run just fine inside an OpenVZ container. Applications and services do not have to be aware of OpenVZ. However, direct access to hardware is not available by default.
 
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===== How is OpenVZ different from other technologies? =====
 
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:See [[Introduction to virtualization]].
 
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===== How is OpenVZ secured & updated? =====
 
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:See [[Security]].
 
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===== How scalable is OpenVZ? =====
 
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OpenVZ technology scales as well as standard Linux kernel — up to thousands of CPUs and terabytes of RAM. Besides, a single container could be scaled up from taking a little fraction of available resources up to all resources available dynamically — you do not even have to restart the container. For example, containers can natively use up to all available CPUs which is different from hypervisor technology which requires special tricks like co-scheduling and even the best hypervisors are inefficient with more then 4-8 vCPUs.
 
  
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===== How does OpenVZ improve efficiency of services? =====
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===== So what is Virtuozzo? =====
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Virtuozzo is a Linux based virtualization platform, combining container and hypervisor virtualization, into a single product. While primarily built for service providers to run cloud services and applications, it is used by variety of businesses, including MSP, SMB and Enterprises.
  
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For existing hardware, OpenVZ allows to utilize its processing power better by improving average load from 3-5% to at least 30-50%, while still providing ability to handle peak loads. To decrease complexity, OpenVZ provides standardized and centralized server management, logically decoupled from actual hardware. And when its time to buy new servers, you can now use few more powerful servers instead of many little ones — with added benefits of better reliability, better peak performance and typically longer lifespan.
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===== What is OpenVZ and how it compares to Virtuozzo? =====
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OpenVZ is a free and opensource portion of Virtuozzo. It includes core of Virtuozzo functionality, like kernel and command line management tools for creating and managing containers. Virtuozzo includes everything that OpenVZ does, plus additional features and services available with the commercial version only.  
  
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===== How does OpenVZ improve flexibility of services? =====
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===== How does Virtuozzo 7/OpenVZ pair compares to its predecessor (Virtuozzo versions 4.x and 6/OpenVZ) =====
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Previously, OpenVZ and Virtuozzo were built out of the same code base with some unique patches applied. That warranted the user interfaces to be similar but not identical. With Virtuozzo 7, the compatibility will be on the binary level - effectively the open source components will be the same between OpenVZ and Virtuozzo.
  
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By providing unified scalable platform with such unique features as rapid application and updates provisioning. Each container is hardware independent and can be moved to another OpenVZ-based system in seconds over the network. This allows for ease of hardware maintenance (move out all containers and do whatever you need with the box) and improved availability (keep a synchronized copy of your container elsewhere and start it up when primary service failed). If your old box is not able to cope with peak load anymore, just move your containers to a new one.
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===== How OpenVZ users will benefit from it? =====
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OpenVZ components will be undergoing the same testing procedures as the commercial product. Also, some new features previously available on Virtuozzo only (notably hypervisor) will become available on the product built for OpenVZ community users.
  
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===== What is the performance overhead? =====
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===== What support options are available for Virtuozzo 7? =====
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For the moment, only preview (beta) versions of Virtuozzo 7 are available. They are intended for development and testing only, not for production. Virtuozzo 7 is not yet commercially supported. For supported commercial version, please refer to [http://www.odin.com/products/virtuozzo/ Virtuozzo 6].
  
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Near zero. There is no emulation layer, only security isolation, and all checking is done on the kernel level without context switching.
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===== Why I need Virtuozzo/OpenVZ when LXC exist? =====
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See our [[comparison]] of different virtualization solutions.
  
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===== What are performance expectations? =====
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===== When OpenVZ will be in upstream kernel? =====
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Our kernel developers [http://openvz.org/File:Kernel_patches_stats.png work hard] to merge containers functionality into the upstream Linux kernel, making OpenVZ team the biggest contributor to Linux Containers (LXC) kernel, with features such as PID and network namespaces, memory controller, checkpoint-restore and much more.
  
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Peak performance is achieved when only one container has active tasks. In this case, it could use 100% of available resources: all CPUs, all physical memory, all disk and network bandwidth. OpenVZ is not limiting you to a single-CPU virtual machine.
 
  
 
===== I want to show my appreciation to OpenVZ and put some logo to my site. Where to get it? =====
 
===== I want to show my appreciation to OpenVZ and put some logo to my site. Where to get it? =====
 
:See [[Artwork]].
 
:See [[Artwork]].
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===== Are there any control panels available for OpenVZ? =====
 
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:See [[Control_panels]]. [http://code.google.com/p/ovz-web-panel/ OVZ Web panel] is recommended.
 
  
 
===== What kind of documentation is available? =====
 
===== What kind of documentation is available? =====
  
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:Aside from this wiki, which contains lots of information, you can check extensive [[Man|manual pages]].
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:Aside from this wiki, which contains lots of information, you can check extensive [[Man|manual pages]] and [http://docs.openvz.org Virtuozzo documentation].
  
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== Installation and upgrade ==
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===== Who needs OpenVZ? How it can be used? =====
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:See [[Use cases]].
  
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===== What hardware is supported by OpenVZ kernel? =====
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===== How scalable is OpenVZ? =====
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:See [http://www.parallels.com/en/products/virtuozzo/hcl/ Virtuozzo HCL].
 
  
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===== Why there are different kernel flavours available and what do they mean? =====
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OpenVZ technology scales as well as standard Linux kernel — up to thousands of CPUs and terabytes of RAM. Read more about [[WP/Containers_density|OpenVZ containers density]] and [[performance]].
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:See [[Different kernel flavors (UP, SMP, ENTERPRISE, ENTNOSPLIT)]].
 
  
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===== How do I rebuild the kernel? =====
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== Installation and upgrade ==
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:See [[Kernel build]].
 
  
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===== What does 021stab018 in OpenVZ kernel version mean? =====
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===== How to install OpenVZ? =====
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:See [[Kernel versioning]].
 
  
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===== How can I check package signatures? =====
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There are two versions of OpenVZ available:
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:See [[Package signatures]].
 
  
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===== Is it possible to run x86 container on a x86_64 arch? =====
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* [[Roadmap|stable version]]: OpenVZ legacy (based on RHEL5 and RHEL6 kernels).
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:Sure :) We actually did some work on that to enable migration of x86 container from x86 to x86_64 and back, and to enable using 32-bit iptables in 32bit container on an x86_64 system.
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* [[Roadmap|development version]]: [[Virtuozzo]] Linux distribution based on RHEL7 kernel.
  
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===== What filesystems should I choose for saving my containers? =====
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See [[Quick installation]]
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: Currently, ext4 is recommended. Any filesystem which supports Unix style permissions is usable, such as Ext3 or ReiserFS. XFS works, but does not have support for disk quotas inside containers.
 
  
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== Networking ==
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===== What hardware is supported by OpenVZ kernel? =====
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:See [https://hardware.redhat.com/ RHEL Hardware Compatibility List].
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===== How do I set up VPN for a container? =====
 
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:See [[VPN via the TUN/TAP device]].
 
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===== What is veth and how do I use it? =====
 
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:See [[Virtual Ethernet device]].
 
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===== Why doesn't net-snmpd work on my containers? =====
 
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:See [[SNMPD in container]].
 
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===== Can I use private IPs for my containers? =====
 
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:See [[NAT]].
 
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== User Beancounters (UBC) ==
 
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===== What are those User Beancounters? =====
 
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See [[UBC]].
 
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===== What units are UBC parameters measured in? =====
 
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See [[UBC parameter units]].
 
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===== How do I set up a container which is able to get X Mb of RAM? =====
 
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See [[Setting UBC parameters]].
 
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===== I can not start a program in container: it reports out of memory. What do I do? =====
 
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See [[Resource_shortage]].
 
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===== How can I reset <code>failcnt</code> in <code>/proc/user_beancounters</code>? =====
 
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See [[UBC failcnt reset]].
 
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== Troubleshooting ==
 
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===== My kernel crashed. What should I do? =====
 
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:See [[When you have an oops]].
 
  
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===== I see a lot of processes in D state. What does that mean? =====
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===== How existing OpenVZ users can upgrade to the [[Virtuozzo|new version]]? =====
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:See [[Processes in D state]].
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While there is no in-place upgrade, we prepared [[Upgrade_script_from_OpenVZ_to_Virtuozzo_7|upgrade script]] for OpenVZ users to move their containers to the new platform. The script allows to transfer containers from old to new OpenVZ version (or from OpenVZ to Virtuozzo).

Latest revision as of 10:18, 9 January 2021

Openvz-logo.png This article is for Virtuozzo 7 only.

General[edit]

So what is Virtuozzo?[edit]

Virtuozzo is a Linux based virtualization platform, combining container and hypervisor virtualization, into a single product. While primarily built for service providers to run cloud services and applications, it is used by variety of businesses, including MSP, SMB and Enterprises.

What is OpenVZ and how it compares to Virtuozzo?[edit]

OpenVZ is a free and opensource portion of Virtuozzo. It includes core of Virtuozzo functionality, like kernel and command line management tools for creating and managing containers. Virtuozzo includes everything that OpenVZ does, plus additional features and services available with the commercial version only.

How does Virtuozzo 7/OpenVZ pair compares to its predecessor (Virtuozzo versions 4.x and 6/OpenVZ)[edit]

Previously, OpenVZ and Virtuozzo were built out of the same code base with some unique patches applied. That warranted the user interfaces to be similar but not identical. With Virtuozzo 7, the compatibility will be on the binary level - effectively the open source components will be the same between OpenVZ and Virtuozzo.

How OpenVZ users will benefit from it?[edit]

OpenVZ components will be undergoing the same testing procedures as the commercial product. Also, some new features previously available on Virtuozzo only (notably hypervisor) will become available on the product built for OpenVZ community users.

What support options are available for Virtuozzo 7?[edit]

For the moment, only preview (beta) versions of Virtuozzo 7 are available. They are intended for development and testing only, not for production. Virtuozzo 7 is not yet commercially supported. For supported commercial version, please refer to Virtuozzo 6.

Why I need Virtuozzo/OpenVZ when LXC exist?[edit]

See our comparison of different virtualization solutions.

When OpenVZ will be in upstream kernel?[edit]

Our kernel developers work hard to merge containers functionality into the upstream Linux kernel, making OpenVZ team the biggest contributor to Linux Containers (LXC) kernel, with features such as PID and network namespaces, memory controller, checkpoint-restore and much more.


I want to show my appreciation to OpenVZ and put some logo to my site. Where to get it?[edit]
See Artwork.
What kind of documentation is available?[edit]
Aside from this wiki, which contains lots of information, you can check extensive manual pages and Virtuozzo documentation.
Who needs OpenVZ? How it can be used?[edit]
See Use cases.
How scalable is OpenVZ?[edit]

OpenVZ technology scales as well as standard Linux kernel — up to thousands of CPUs and terabytes of RAM. Read more about OpenVZ containers density and performance.

Installation and upgrade[edit]

How to install OpenVZ?[edit]

There are two versions of OpenVZ available:

See Quick installation

What hardware is supported by OpenVZ kernel?[edit]
See RHEL Hardware Compatibility List.
How existing OpenVZ users can upgrade to the new version?[edit]

While there is no in-place upgrade, we prepared upgrade script for OpenVZ users to move their containers to the new platform. The script allows to transfer containers from old to new OpenVZ version (or from OpenVZ to Virtuozzo).

Retrieved from "https://wiki.openvz.org/index.php?title=FAQ&oldid=23371"