Machine virtualization or OS level virtualization (KVM vs OpenVZ)?

Question

OpenVZ

There is a server on Xeon E3 and there are services.
There is a need to place these services on this server.
More or less familiar with machine virtualization (Xen, VMWare, VirtuaBox).
C virtualization at the OS level is not familiar at all.

Hence the question:
What to choose?

More about services:
various sites,
sites on Bitrix (which require special php settings and are incompatible with other sites),
zabbix,
EDMS (Motive comes with its own set of Apache, php, java software, the settings of which are incompatible with other sites).

It is possible to add other services (it's hard to imagine what, but it can be anything from SVN to Elastix, Alfresco, etc.).

The question, of course, is of interest in terms of performance, stability and other points important for production.

Answer 1

You need to understand what it is, why it is needed, how to manage it.
1. virtualization at the machine level is a complete abstraction of a virtual machine from hardware.
2. virtualization at the kernel level is the division into virtual machines of everything that is better to single out separately - dns server, dhcp, apache, then when breaking through, say, the dns server, apache with a client control panel will remain alive. Advantages - that it's easier to update than a dozen separate virtual machines. but if you need to virtualize, say, Windows, then virtualization at the kernel level is no way. In my opinion, even fribsd was started under Linux, but I won’t lie. But kernel-level virtualization requires kernel preparation. better to carefully read about hyung, kwm

Answer 2

I agree with foxmuldercp, I will only note that if the question is only about separating php settings (including modules), then you can do without virtualization at all.
All the same, each virtual machine will need a separate ip - you can hook a separately compiled apache + php + the rest to this ip. Separately compiled - in the sense of your personal isolated directory (./configure --prefix=path ..), with your modules and personal .ini/.conf files.
This option is the most economical in terms of server resources, management is also no more difficult than managing individual virtual machines. Plus, there is the possibility of simple sharing of file resources, tk. symlinks and hardlinks work for the entire server, and not just within the virtual machine.

Answer 3

Take LXC + lxctl, you can't go wrong.
Problems with IP can be solved with gray IP for virtual machines and nginx on the hardnode.

Answer 4

Well, yes - chroot in your case is also enough if you put nginx in front.

Answer 5

Thanks for answers.
But with OpenVZ (since I have never encountered it) there is one point that I can’t understand in any way.
Here XEN and other full-fledged virtual machines completely emulate the system, i.e. own OS, ssh, etc.
And this is done quite simply.
Does OpenVZ allow you to do the same? Those. emulate a full-fledged OS with its own set of packages.
In windows, I think the need is not foreseen in the near future. The OS will all probably be CentOS.
The server is internal, i.e. there will be no access to clients, so the issue of hacking neighbors (as on VPS) is not acute.
There is also a question with the cohabitation of these 2 technologies.
Those. If I choose OpenVZ, will it be difficult to add KVM to the same server in the future?
How are things going with USB device forwarding in OpenVZ and KVM? (device e.g. USB Digital Thermometer MP707)

Answer 6

I set myself OpenVZ for this, but it’s better to install it on CentOS or RedHat with VSwap mode, otherwise it will crookedly calculate memory.
There were some problems with iptables when I had to set up openvpn, but in general everything works fine.

Answer 7

OpenVZ is a bit less overhead, but a lot more glitches and problems and less isolation than with XEN, KVM, ESXi, etc.
Minimal overhead with a banal chroot, but also minimal isolation. You can set it up, but it’s usually harmful to do so and it will be more difficult to maintain than individual virtual machines, oddly enough.
I chose to solve a similar problem KVM. 2 servers, Separate virtual machines for several services (mail, database, dns, proxy, backup/monitoring/management), one for standard sites, several for sites with a specific environment. In order not to waste ip, where it is not needed, nginx stands as a proxy. When there is no zoo from different OC / distributions, managing such a set of virtual machines is quite simple, even without additional software.