procstat data missing fields mentioned in documentation

[rj33]

Bug report

The procstat plugin documentation mentions the following stats that don't appear to be arriving:
procstat_[prefix_]read_count value=396
procstat_[prefix_]write_count value=1
procstat_[prefix_]read_bytes value=1019904
procstat_[prefix_]write_bytes value=1

procstat_[prefix_]num_fds value=4

Relevant telegraf.conf:

[[inputs.procstat]]
exe = "foo"

System info:

telegraf_1.0.0-beta3

Ubuntu 14.04.1

Steps to reproduce:

1. Set any inputs.procstat plugin in telegraf.conf
2. Restart telegraf
3. Check incoming data

Expected behavior:

Stats included for things num_fds

Actual behavior:

Additional info:

num_fds and the io stats are not included, looking at the measurement in innodb I see these fields only:
cpu_time_guest cpu_time_guest_nice cpu_time_idle cpu_time_iowait cpu_time_irq cpu_time_nice cpu_time_soft_irq cpu_time_steal cpu_time_stolen cpu_time_system cpu_time_user cpu_usage exe host involuntary_context_switches memory_rss memory_swap memory_vms num_threads pid process_name voluntary_context_switches

[andrii-rymar]

I'm able to reproduce this with Telegraf 1.2.0-1 and 1.2.1-1 on CentOS 6.5 x64

[cchanning]

Hi, this may need to be reopened. I've just tested this again on version 1.3.4 running on Ubuntu 16.04 as root. I'm getting the following fields after running (telegraf -test -config telegraf.conf):

procstat,exe=dd,process_name=dd,host=8196018c6b73 cpu_time_steal=0,cpu_time_stolen=0,memory_rss=1075146752i,num_threads=1i,involuntary_context_switches=18i,cpu_time_iowait=0,cpu_time_irq=0,pid=3395i,cpu_time_guest=0,memory_vms=1078280192i,cpu_usage=3.9598084197168877,num_fds=3i,voluntary_context_switches=131i,cpu_time_user=0,cpu_time_system=1.9,memory_swap=0i,cpu_time_idle=0,cpu_time_nice=0,cpu_time_soft_irq=0,cpu_time_guest_nice=0 1500637292000000000

The target process running is dd (dd if=/dev/zero of=/root/testfile bs=1G count=8 oflag=direct). The telegraf config is the default with the procstat plugin uncommented and the exe parameter set as 'dd'.

As you can see, all of the disk I/O metrics are missing.

[danielnelson]

When these stats are missing it generally means that Telegraf does not have permission to read the necessary files in /proc/${pid}/. The easiest way to get this to work is to run Telegraf as root, but I don't recommend it.

[cchanning]

Hi Daniel, thanks for responding. As I mentioned in my earlier comment though, telegraf was running as root when I ran the test.

[danielnelson]

The io stats are read from /proc/${pid}/io, can you cat that file?

[cchanning]

Hey, I've done some further investigation on this issue and it appears to be related to docker on Mac rather than to Telegraf. Sorry for the noise =)

[danielnelson]

No problem, I'd love to hear the details if you have time.