Attend Linux Container Developers Meeting

When management suggested that I attend a meeting of Linux container developers , I initially thought about giving up. To go 500 km to Moscow and back, to spend the day on my feet, and I’m not even a developer, I’m a sysadmin who uses OpenVZ technology in his work ...

But, after reading the program, I realized that the meeting was designed not only and not so much for the developers, but also for the active users of this beautiful creation from Parallels.
And putting the latest beta Virtuozzo 7, also made a list of questions that I would like to clarify.
')




The meeting was held under the auspices of Yandex, I thought I would see how cool they were in offices, but they didn’t take us deep into the corridors, the conference room of the hall-studio type was at the entrance. Overall it was very nice. Those interested could be accommodated next to the conference hall on bean bags ...



A little name magic ...
Parallels makes a lot of great products for virtualization, I think all Apple employees
have seen Parallels Desktop for Mac;)

And in an attempt to avoid confusion, the team of developers of virtualization solutions for service and hosting providers
together with their product Parallels Cloud Server was given a separate name, without the word Parallels:

Team Odin with the product Virtuozzo.

From the information on the site, we can conclude that OpenVZ also ceases to be a standalone free product and becomes mostly Virtuozzo 7, remaining free further, but with paid utilities for automating cloud service.

At the beginning, the speakers from Odin told us that the new Virtuozzo 7 is waiting for us:

As the next version of the free product will be called, they have not yet decided, until the current name is like this: OpenVZ / Virtuozzo 7. Perhaps it will be called simply Virtuozzo 7, which will be offered paid technical support services and farm management modules for host machines with containers, located on distributed storage Virtuozzo Storage ...
Also, unlike OpenVZ, in Virtuozzo 7 there will be KVM-based virtual machines in addition to the containers.

The new version is based on RHEL7 and kernels version 3.10, with all the charms in the form of systemd. The volume of patches in the kernel will be less than in OpenVZ 6, but they will, so containers won't start on the vanilla kernel, you will need to either use their CloudLinux distribution or install vzkernel on Red Hat / CentOS 7.

It will be necessary to stop using vzctl and switch to another prlctl utility, the command syntax of the utilities is almost the same, but prlctl can do much more.

The main difference of the interface is that vzctl operates with container VEIDs (/ vz / private / $ VEID), and prlctl with names and UUIDs (/ vz / private / $ UUID).

symfs is no longer supported, all containers should be in ploop image, so just copy the symfs container via rsync to Virtuozzo 7 and run there will not work.
However, there is a simple recipe for converting manually, and in the future, the developers promised a special utility for migration.
Recipe: you first need to set disk limits on OpenVZ 6, then convert the container to ploop image, and transfer this image to Virtuozzo 7 already.

With the transition to ploop, they promise multiple snapshots with the ability to mount each snepshot, snepshot backups and container migration on the fly ...
All this is already working, except for the online migration of containers.

The problem with Odin is that most of their kernel patches were not accepted from them (apparently due to the large volume and complexity of the audit), so now they embody the functionality of unaccepted patches in user space code. This project is called CRIU. They promise that it will be possible to freeze into a set of files on the disk and restore the state not only of the containers, but also of individual applications. It will be cool, but not soon. Somewhere in 2016 ...

Also, Virtuozzo 7 will use the standard system memory allocation mechanism between containers, but with the help of the VCMMD daemon, you can automatically change the soft memory allocation limits for containers on the fly, increasing the efficiency of resource utilization of the host machine.

Another speaker, CEO of Rusonix, shared the secrets of the success of the service provider’s business.
In addition to using the purchased full package, Virtuozzo, which makes it much easier to manage a large number of host machines and containers, is brought to its success by an orientation toward a massive standard customer who was sketched with a website store on bitrix. Everyone else is offered a virtualka with root-access for independent navigation.
But we can not, we are always ready to help our clients in any of their requests.

A speaker from CloudLinux talked about the non-standard use of CRIU technology to speed up the launch of php by the apache module. How many places they had to fight heroically in order to use CRIU for their own purposes, but, unfortunately, did not say anything about the practical benefits of this focus, and how it is better than running php through php-fpm.

Starting with the vzkernel 042stab105.4 kernel version, it is possible to launch Docker containers inside openVZ containers, the OpenVZ developers work in close contact with the Docker developers, but the latter is developing so fast that OpenVZ does not have time for it. So, only a certain version of Docker works inside the OpenVZ container;

Installation instructions on the openVZ wiki openvz.org/Docker_inside_CT .
They promise to make Virtuozzo 7 full support for Docker.



Very pleased with the final speaker Dmitry Monakhov. With his energy and charisma, he literally blew up the already tired hall. And everyone listened with great interest to the story of what happens when a file system created to work on the expanses of physical disks is driven into the Procrustean bed of the virtual image. And what interesting problems have to be solved when creating additional supporting utilities. It was fun and informative.

Slides and video reports can be viewed here: events.yandex.ru/events/yagosti/19-september-2015-linux