Linux container developers meeting

This year, the OpenVZ project will be 10 years old . We developed the technology of isolated environments for Linux OS even when it was not fashionable. September 19, we gather the first meeting of people from the OpenVZ community , those who use our technologies and Linux containers in general. Listen to the reports of OpenVZ users and developers, ask them questions, talk in breaks.







Parallels / Odin, the distinguished speaker of the company and Pavel Emelyanov, the developer of OpenVZ and CRIU projects, will open the session of the reports with his report on the migration of containers. Pavel was involved in the container migration technology in Virtuozzo / OpenVZ, and later became the initiator and mentor of the CRIU project, so he ate the dog on migration. Pavel will tell about all the pros and cons of live container migration, about the principles of CRIU operation and will tell about the new subproject of P.Haul (aka “pihl”) .

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For a long time OpenVZ had its own implementation of container memory management technology. The developers went through several fires, water, and copper pipes with several implementations of this technology , but in Virtuozzo 7 based on the RHEL7 core, memory management will be implemented only on the basis of vanilla core technologies. Thus, in this part of the kernel, OpenVZ will not leave our core patches at all. Vladimir Davydov, the author of the new memory management technology in OpenVZ, will tell more about all this.



There are several paradigms of using containers: using as a full-fledged operating system isolated from the host OS (LXC, OpenVZ / Virtuozzo) and as an isolated environment for a single application (Docker). LibCT is a library that allows you to create isolated environments and manage resources. The basic idea is to bring containers to the application level. Now the use of container functionality is hampered by the complexity of using kernel interfaces and the heterogeneity of resource management at the user level. In addition, different operating systems have different interfaces. LibCT will help to forget about these problems and provide a single interface. Sasha Burluka is developing LibCT, so he will be able to answer even the most tricky questions about this library.



Hosting is only one of the options for using Linux containers. The containers changed the perception of DevOps processes, allowing you to smoothly move from one stage of application development to another (development, testing, stage and production), and also use microservice architecture. That is why many cloud platforms have already implemented container technologies in the “pipeline” of developing and launching applications. DevOps and containers help you more effectively implement business plans. In the report we will look at the current situation on the market for DevOps and containers. We will also discuss the well-known problems of this direction and how to solve them for highly loaded complex applications located in containers. Dmitry Lazarenko from Jelastic will talk about his experience in using OpenVZ for DevOps tasks.



Initially, containers were positioned as a technology for hosting - the provider had to be able to share the environments of different users, set different parameters for these environments depending on the tariff plan, etc. That is, the idea of ​​using containers in hosting is not new. OpenVZ is popular among hosts. But in order to attract users to themselves, hosters must differ from each other. Rusonix is ​​one of the oldest hosting companies in the Russian Internet hosting market and those companies that have chosen OpenVZ. Konstantin Anisimov (CEO of Rusonix) in his report will tell about the reasons why they chose Virtuozzo and what advantages the hosting provider gives using container technology.



CloudLinux is a Linux distribution with its own shared hosting (LVE (lightweight virtual environment), CageFS). Ruslan Kupreev works for CloudLinux and at the same time is the developer of CRIU (Checkpoint and Restore In Userspace) . They use CRIU in the Apache mod_lsapi web server module to speed up PHP startup. How it works and how much PHP startup speeds up you will learn from the report of Ruslan.



After there was a boom in the approach to container management, and Docker appeared on the market, hosting users wanted to be able to run Docker containers in regular VPS. OpenVZ provides this feature. Pavel Tikhomirov will talk about how to use Docker inside Virtuozzo containers, what is the difference between approaches to containers in Virtuozzo and Docker, what are their pros and cons and why it is useful to combine them. In addition, some technical solutions, examples of using Docker in Virtuozzo and current plans will be considered.



Most existing virtualization solutions use virtual disks (block devices). The most important feature of such disks is “thin provision” (the ability to allocate space only when necessary). But a serious disadvantage of this property is the “smearing” of data on the disk in the process of work. The size of the disk image is constantly growing, even if the amount of actually used data remains constant. As a result, blocks that are allocated but not used by the file system are accumulated on the virtual disk. Dmitry Monakhov will tell how the teams of the Virtuozzo and CRIU projects together with LKML solve this problem and why existing mechanisms are not enough.



Participation in the meeting is free, but you need to register .



If for some reason you cannot participate, then you will be able to see the recordings of speeches that Yandex promised to post.