[Announce] OpenVZ 7.0 released

Sergey Bronnikov sergeyb at openvz.org
Mon Jul 25 12:40:58 PDT 2016

I’m pleased to announce the release of OpenVZ 7.0. The new release focuses on
merging OpenVZ and Virtuozzo source codebase, replacing our own hypervisor with

Key changes in comparison to the last stable OpenVZ release:

* OpenVZ 7.0 becomes a complete Linux distribution based on our own VzLinux.

* The main difference between the Virtuozzo (commercial) and OpenVZ (free)
versions are the EULA, packages with paid features, and Anaconda installer.

* The user documentation is publicly available [1].

* EZ templates can be used instead of tarballs with template caches.

* Additional features (see below)

This OpenVZ 7.0 release provides the following major improvements:

* RHEL7 (3.10+) kernel.

* KVM/QEMU hypervisor.

* Guest tools for virtual machines that currently allow the following: to
execute commands in VMs from the host, to set user passwords, to set and obtain
network settings, to change SIDs, to enter VMs.

* Unified management of containers and KVM virtual machines with the prlctl tool
and SDK. You get a single universal toolset for all your CT/VM management needs.

* UUIDs are used to identify both virtual machines and containers. With
containers, prlctl treats the former VEID parameter as name.

* Virtual machine HDD images are stored in the QCOW2 format.

* Ability to manage containers and VMs with libvirt and virt-manager or virsh
via a single driver for containers and virtual machines. Libvirt is an
open-source API, daemon, and management tool for managing virtualization
platforms. The API is widely used in the orchestration layer of hypervisors for
cloud-based solutions. OpenVZ considers libvirt as the standard API for managing
both virtual machines and containers. Libvirt provides storage management on the
physical host through storage pools and volumes which can be used in OpenVZ

* Memory guarantees. A memory guarantee is a percentage of container's or
virtual machine's RAM that said container or VM is guaranteed to have.

* Memory hotplugging for containers and VMs that allows both increasing and
reducing CT/VM memory size on the fly, without the need to reboot. Your
customers can now scale their workloads without any downtime. This feature also
enables you to make PAYG offerings, allowing customers to change VM resources
depending on workload and potentially pay less.

* Kernel same-page merging. To optimize memory usage by virtual machines, OpenVZ
uses a Linux feature called Kernel Same-Page Merging (KSM). The KSM daemon ksmd
periodically scans memory for pages with identical content and merges those into
a single page.

* VCMMD, the fourth-generation unified memory manager, and vcmmd, a single
daemon for managing memory of both virtual machines and containers. OpenVZ 7
uses memcg. Balancing and configuring memcg limits enables getting the exact
OpenVZ parameters like overcommit, shadow gangs, swap, page cache overuse.

* Container live migration via CRIU and P.Haul. In the previous versions of
OpenVZ, most operations performed during migration were done in the kernel
space. As a result, the migration process imposed a lot of restrictions. To
improve upon migration, Virtuozzo launched the CRIU project aiming to move most
of the migration code to the user space, make the migration process reliable,
and remove excessive restrictions.

* Containers use cgroups and namespaces that limit, account for, and isolate
resource usage as isolated namespaces of a collection of processes. The
beancounters interface remains in place for backward compatibility and, at the
same time, acts as a proxy for actual cgroups and namespaces implementation.

* SimFS remains in OpenVZ 7.0, however, the support is limited and we don't have
plans to improve it in future.

Known Issues

* OpenVZ 7 includes vzctl from the commercial version. This means there is no
backward compatibility for the previous version of vzctl from OpenVZ.

* vzctl will be obsoleted in next version of OpenVZ, consider switching to
prlctl or virsh.

* The full list of known issues and limitations is provided in the documentation [1].


All binary components as well as installation ISO images are freely available at
the OpenVZ download server [2] and mirrors [3]. The source code of each
component is available in the public repository [4].


Q: Can we use the binaries of OpenVZ/Virtuozzo 7.0 distribution in production?
A: Yes.

Q: Is it possible to upgrade OpenVZ based on 2.6.32/2.6.18 to the OpenVZ/Virtuozzo 7?
A: Yes! Please follow the instructions in the OpenVZ 7 Upgrade Guide [1].


Our switching to the open development process is an attempt to work more closely
with the OpenVZ community. You can help us by sending your feedback to the
users@ mail list or submitting a bug in case of a serious issue [5].


[1] https://docs.openvz.org/
[2] https://download.openvz.org/virtuozzo/releases/7.0/x86_64/iso/
[3] https://mirrors.openvz.org/
[4] https://src.openvz.org/projects/OVZ
[5] https://bugs.openvz.org/


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