Resource monitoring in an OpenVZ environment can be done by using different commands and tools specifically designed for this purpose.
For instance, vzstat utility can provide real-time statistics about the resource usage for all the containers simultaneously.
For more detailed information about a specific container, you can use the vzlist command. Example:
```
vzlist -o ctid,cpu,diskspace,privvmpages -H VPSID
```
This command will display the CPU usage, disk space, and memory usage of the container indicated by VPSID.
You can also use vzcalc to calculate current and average consumption of different resources. For example:
```
vzcalc -v VPSID
```
In addition, you have the vzmemcheck tool which can provide more in-depth statistics about memory usage.
Finally, you can regularly monitor your log files in /var/log/vzctl.log for any unusual activities or errors. Analyzing log files can provide valuable information about the performance of your containers and help you troubleshoot potential issues.
Please note that for using these commands you should have root access to the hardware node running the OpenVZ containers.
