Containers and CPU utilization

LXD
1

Hello to everyone . Is there a way that I can check for each container that i have create , cpu utilization and all this stuff from the command line ? Something like the top command maybe ?

2

Short answer not really

Long answer you can get there or there abouts but its work (hopefully someone has some nifty script)

3

Isn’t there something like top command ? I found lxc-top but it shows nothing despite i have create a container. In fact i create the container through lxd , so i guess it is normal that lxc-top gives me zero output

4

Yeah if you wanna see the process, go on the host install htop, run htop press f5 (tree) then f3 (search) yourContainerName it will show you all the processes

5

LXD has lxc info mycontainer, which gives you some information.

Each Linux container is essentially a process tree that is separated from the rest of the host’s processes through cgroups. What you need, is software that understands cgroups and groups together the load of each process tree (a.k.a. Linux container).
See, for example, ctop.

Alternatively, there are tools like netdata that you install on the host and can give you instant insight into the containers.

6

Thanks a lot both of you for your answers.

7

Hi Thodoris,
here is a shell script, that you maybe can extend to your needs:

#!/bin/bash

lxc_list=$(lxc list --format=json | jq '.[] | "\(.name) \(.state.memory.usage) \(.state.processes) \(.state.cpu.usage) \(.state.network.eth0.counters.bytes_received) \(.state.network.eth0.counters.bytes_sent)"')
format="%15s %16s %12s %18s %12s %12s\n"
printf "$format" name memusage procs cpu recv sent
while IFS=\  read name memusage processes cpuusage bytes_received bytes_sent; do
     name=$(echo "$name"|cut -c 2-)                     # remove the first character (a quote)
     bytes_sent=$(echo "$bytes_sent"|rev|cut -c 2-|rev) # remove the last character (a quote)
     printf "$format" $name $(echo "$memusage"|numfmt --to=si --suffix=B) \
                      $processes \
                      $cpuusage \
                      $(echo "$bytes_received"|numfmt --to=si --suffix=B) \
                      $(echo "$bytes_sent"|numfmt --to=si --suffix=B)
done <<< "$lxc_list"

It creates something like:

           name         memusage        procs                cpu         recv         sent
  lxd-dashboard            299MB          120       129182767000         50KB         14KB
      nextcloud            116MB          255      3027363446000        777MB        115MB
    rocket-chat            377MB          120       109302610000         44KB         15KB
       ubuntu22            267MB          122       137490014000         57KB         14KB
      wordpress            335MB          120       122135800000         54KB         14KB

Btw, @Stephane (maybe knows that): What unit has cpu.usage? How to show some more meaningful? (like a percentage of the host-cpu i.e. - any idea?)

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8

@tkasidakis
Have a look at systemd-cgtop e.g. systemd-cgtop --depth=1 -p
otherwise you can use lxc exec <container> -- [top | htop | btop | etc...]
GNU Parallel will also help you run things in … well parallel :slight_smile:.

9

LXD does have metrics exporter and a Grafana dashboard you can use for this, see:

10

I simplyfied this aproach to be put into an shell alias:

alias lxcstats="printf \"%-20s %-8s %-5s %-5s %-s\n\" name status mem disk cpu-time; lxc list status=running --format=json | \
  jq  -r '.[] | \"\(.name) \(.status) \(.state.memory.usage) \(.state.disk.root.usage) \(.state.cpu.usage)\"' | \
  numfmt --field=3,4 --to=iec|\
  printf '%-20s %-8s %-5s %-5s %(%-dd %-Hh %-Mm )T\n' \$(</dev/stdin)"

btw: state.cpu.usage are cpu miliseconds

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