Monitoring Processes in Real Time

The vztop utility is rather similar to vzps but is usually started full-screen and updates continuously with process information. This can help with programs that may infrequently cause problems and can be hard to see with vzps. Overall system information is also presented, which makes a nice place to start looking for problems.

The vztop utility can be run on the server just as the standard Linux top utility. The only features that distinguish the vztop utility from top are the following:

• vztop allows you to use the -E option that monitors only the processes belonging to the Container whose processes you want to display.
• You can use the e interactive command to temporarily view/hide the CTIDs where the processes are running.
• You can use the E interactive command to set the filter on the CTID field that helps you display only the processes belonging to the given Container.

The vztop utility usually has an output like the following:

# vztop -E 101

17:54:03 up 20 days, 23:37, 4 users, load average: 2.13, 1.89, 1.75

305 processes: 299 sleeping, 3 running, 3 zombie, 0 stopped

CPU0 states: 20.1% user 51.2% system 0.0% nice 0.0% iowait 28.1% idle

CPU1 states: 21.2% user 50.0% system 0.0% nice 0.0% iowait 28.1% idle

Mem: 1031088k av, 969340k used, 61748k free, 0k shrd, 256516k buff

509264k active, 330948k inactive

Swap: 4056360k av, 17156k used, 4039204k free 192292k cached

CTID PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

101 27173 root 16 0 1616 604 1420 S 0.0 0.1 0:01.86 init

101 27545 root 16 0 1520 624 1356 S 0.0 0.1 0:00.34 syslogd

101 27555 root 25 0 4008 1700 3632 S 0.0 0.4 0:00.04 sshd

101 27565 root 25 0 2068 860 1740 S 0.0 0.2 0:00.05 xinetd

101 27576 root 16 0 7560 3180 6332 S 0.0 0.7 0:03.78 httpd

101 27587 root 16 0 2452 1036 1528 S 0.0 0.2 0:00.34 crond

101 27596 root 25 0 4048 1184 3704 S 0.0 0.2 0:00.01 saslauthd

As you can see, vztop provides an ongoing look at the processor activity in real time (the display is updated every 5 seconds by default, but you can change that with the d command-line option or the s interactive command). It displays a list of the most CPU-intensive tasks on the system and can provide an interactive interface for manipulating processes. It can sort the tasks by CPU usage, memory usage, and runtime. Specifying 101 after the -E option allows you to display only those processes that are running inside Container 101 only. Besides, most features can be selected by an interactive command, for example, the e and E commands described above.

Note: In the current version of Virtuozzo, you cannot use the vztop utility for monitoring processes in virtual machines.