OpenVZ Interview Question:

Explain resource management in OpenVZ?

Submitted by: Administrator

OpenVZ resource management consists of four components: two-level disk quota, fair CPU scheduler, disk I/O scheduler, and user beancounters. These resources can be changed during container run time, eliminating the need to reboot.

Two-level disk quota

Each container can have its own disk quotas, measured in terms of disk blocks and inodes (roughly number of files). Within the container, it is possible to use standard tools to set UNIX per-user and per-group disk quotas.
CPU scheduler

The CPU scheduler in OpenVZ is a two-level implementation of fair-share scheduling strategy.

On the first level, the scheduler decides which container it is to give the CPU time slice to, based on per-container cpuunits values. On the second level the standard Linux scheduler decides which process to run in that container, using standard Linux process priorities.

It is possible to set different values for the CPUs in each container. Real CPU time will be distributed proportionally to these values.

In addition to the above, OpenVZ provides ways to:

set strict CPU limits, such as 10% of a total CPU time
limit number of CPU cores available to container
bind a container to a specific set of CPUs
Submitted by: Administrator