LinuxTag 2009: Resource Management with OpenVZ
OpenVZ project leader Kir Kolyshkin clarified at LinuxTag 2009 that the software also lends itself to Linux resource management.
The facts are clear, Koyshkin said at the outset: every computer has but finite resources such as CPU time, memory, hard disk size and I/O, and network I/O. Administrators are interested in protecting these resources from DoS attacks so that they can continue providing QoS or simple processing.
The Linux kernel already provides resource management tools, said Kolyshkin: disk quotas, nice and renice, the real-time priority queue and limits on CPU time with ulimit -c. Ulimit alone controls 16 different parameters. However, Kolyshkin doesn't find this pallet to be enough. Some limits can't be set and the others are done so at login and can't subsequently be regulated. This is where Kolyshkin brought OpenVZ into the picture. The software allows creating multiple isolated userspace instances, called containers, on a single kernel. Webhosters, for example, could use these containers for their services. From a resource management viewpoint, containers are simply groups of processes.
OpenVZ brings its own resource control mechanisms, called beancounters, that have access to 20 parameters modifiable for process groups at runtime. These groups can be containers, users or applications. For example, the Apache 2 webserver has many processes that could more sensibly combined into application groups. OpenVZ categorizes these user beancounters (UBCs) on its wiki page.
Kolyshkin revealed that further mainline kernel control mechanisms are available through control groups (cgroups) developed over the years by the big iron folks at Bull and SGI. Paul Menage was responsible for bringing cgroups into the Linux kernel for grouping processes for binding memory controllers. Cgroups, however, don't offer as many features as OpenVZ's beancounters, although Kolyshkin wishes for future OpenVZ features such as shared pages accounting, I/O priorities per cgroup and checkpoint/recreate. The latter freezes the state of a group and is used by container or virtualization software such as OpenVZ and Xen for live migration. Further details are in the /usr/src/linux/Documentation/cgroups/* and /controllers/* directories of the kernel source code.
Kolyshkin would love to see the OpenVZ container features integrated into the mainline kernel, but that will "take years." But he's thinking of the future: integration of checkpoint/recreate in the official Linux kernel.
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Armbian 24.11 Released with Expanded Hardware Support
If you've been waiting for Armbian to support OrangePi 5 Max and Radxa ROCK 5B+, the wait is over.
-
SUSE Renames Several Products for Better Name Recognition
SUSE has been a very powerful player in the European market, but it knows it must branch out to gain serious traction. Will a name change do the trick?
-
ESET Discovers New Linux Malware
WolfsBane is an all-in-one malware that has hit the Linux operating system and includes a dropper, a launcher, and a backdoor.
-
New Linux Kernel Patch Allows Forcing a CPU Mitigation
Even when CPU mitigations can consume precious CPU cycles, it might not be a bad idea to allow users to enable them, even if your machine isn't vulnerable.
-
Red Hat Enterprise Linux 9.5 Released
Notify your friends, loved ones, and colleagues that the latest version of RHEL is available with plenty of enhancements.
-
Linux Sees Massive Performance Increase from a Single Line of Code
With one line of code, Intel was able to increase the performance of the Linux kernel by 4,000 percent.
-
Fedora KDE Approved as an Official Spin
If you prefer the Plasma desktop environment and the Fedora distribution, you're in luck because there's now an official spin that is listed on the same level as the Fedora Workstation edition.
-
New Steam Client Ups the Ante for Linux
The latest release from Steam has some pretty cool tricks up its sleeve.
-
Gnome OS Transitioning Toward a General-Purpose Distro
If you're looking for the perfectly vanilla take on the Gnome desktop, Gnome OS might be for you.
-
Fedora 41 Released with New Features
If you're a Fedora fan or just looking for a Linux distribution to help you migrate from Windows, Fedora 41 might be just the ticket.