From OpenVZ Virtuozzo Containers Wiki
Here we list major project milestones.
- Nov 1999: Alexander Tormasov visited Singapore and proposed a new direction to Sergey Beloussov: container virtualization. He formulated three main components: containers as a set of processes with namespace isolation, file system to share code/ram and isolation in resources.
Indeed it was 1999 when our engineers started adding bits and pieces of containers technology to Linux kernel 2.2. Well, not exactly "containers", but rather "virtual environments" at that time -- as it often happens with new technologies, the terminology was different (the term "container" was coined by Sun only five years later, in 2004).—Kir Kolyshkin, http://openvz.livejournal.com/49158.html
- Feb 2000: office at MIPT is established, 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. Take a look on Virtual Environment 0.4.2 (public beta) files.
- Sep 2000: Andrey Savochkin from MSU started working on User Beancounters.
- Dec 2001: Virtuozzo for Windows project started
- Jan 2002: SWsoft (now known as Virtuozzo) initially released a product for Linux named Virtuozzo
- Feb 2002: First clients in Silicon Valley
- Dec 2004: Initial release of Virtuozzo for Windows 
- 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).
- Jan 2006: Rebase to kernel 2.6.15
- Apr 2006: Port to Fedora Core 5 kernel
- Aug 2006: OpenVZ is available in Debian Linux 
- Aug 2006: Rebase to RHEL 4 kernel 
- Oct 2006: Port to SPARC and PPC
- Nov 2006: Port to 2.6.18 kernel 
- Nov 2006: OpenVZ adds live migration capability 
- Mar 2007: Port to RHEL5 kernel
- Mar 2007: Port to 2.6.20 kernel
- May 2007: Knoppix-based OpenVZ Live CD
- Sep 2007: CentOS-based OpenVZ Live CD
- Jan 2008: Templates for Ubuntu 7.10
- Apr 2008: Rebase to kernel 2.6.25
- Oct 2008: Port to ARM .
- 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.
- 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
- May 2013: OpenVZ maintenance partnership 
- Dec 2014: Parallels announced merging OpenVZ and Parallels Cloud Server into single common open source codebase
- 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 yum repository with Virtuozzo RPM packages and installation ISO image .
- SWsoft Releases Virtuozzo 2.0, Bringing Mainframe-Inspired Functionality to Intel-Based Servers
- SWsoft Announces Virtuozzo for Windows Controlled Release
- SWsoft offers free, open source version of Virtuozzo
- OpenVZ Project Releases Beta for Latest Linux Kernel
- OpenVZ Project Releases Software to Support Fedora Core 5
- Debian Linux Adopts OpenVZ Virtualization Software
- OpenVZ for RHEL4
- Open Source Virtualization for Sun UltraSPARC T1
- OpenVZ Virtualization Software Available for Power Processors
- OpenVZ on PPC and SPARC
- OpenVZ adds live migration capability
- OpenVZ software for Red Hat Enterprise Linux 5
- OpenVZ Virtualization for Latest Linux Kernel
- OpenVZ Live CD
- OpenVZ CentOS Live CD
- OpenVZ Virtual Appliance for Ubuntu
- 2.6.25 is out; memory controller and network namespaces are in
- OpenVZ ported to ARM (Gumstix Overo)
- Linux Kernel Development Report, Aug 2009 update
- Checkpoint/restore mostly in the userspace
- First commit to CRIU (Checkpoint and Restore in Userspace)
- First CRIU public release
- Announce: Checkpoint-restore tool v0.1
- Announcing the OpenVZ Maintenance Partnership
- OpenVZ past and future
- Odin published source code of kernel 3.10
- Odin published source code of Virtuozzo userspace utilities
- Odin published Virtuozzo binaries and installation image