Docker top appears to behave differently than on Linux Systems

Docker Desktop
,
1

Expected behavior

I should be able to retrieve CPU usage information from the process table of a Docker container on Mac.

Actual behavior

Attempting to retrieve CPU usage information causes an error.

Information

Pinata output

OS X: version 10.11.5 (build: 15F34)
Docker.app: version v1.11.1-beta12
Running diagnostic tests:
[OK]      Moby booted
[OK]      driver.amd64-linux
[OK]      vmnetd
[OK]      osxfs
[OK]      db
[OK]      slirp
[OK]      menubar
[OK]      environment
[OK]      Docker
[OK]      VT-x
Docker logs are being collected into /tmp/20160524-105904.tar.gz
Most specific failure is: No error was detected
Your unique id is: C7EE1F29-FE15-48B3-A118-4680F0C7B27B
Please quote this in all correspondence.

Steps to reproduce the behavior

  1. Start a docker container.
  2. Execute docker top [containerid] a -o pid,%cpu

On my Ubuntu system that command produces output like this.

PID                 %CPU
2453                0.0

On my OS X system that command produces this output:

Error response from daemon: Error running ps: exit status 1
2

Hi,

If you have been running the alternative Docker, please can you check you
are not running in a
term which includes settings for it. Try ‘env | grep ^DO’ to make sure
that there are no environment
variables set for the alternative environment/setup.

3

I think pinata checks that for me, but I just checked again and don’t see any such variables.

4

Do everything else work as expected? Quite a few people are reporting issues since upgrading to OS X 10.11.5. Seems like something to do with the /var/run/docker.sock. Workarounds available in other threads.

5

Yeah, everything else is working fine. If this were an issue with the docker socket I wouldn’t even be able to docker ps. I think this has something to do with the instance of ps installed on the xhyve VM that DockerVM is running the docker daemon in…

6

Seems so. On the Docker (for Mac) host:
ps a -o pid,%cpu ps: bad -o argument '%cpu', supported arguments: user,group,comm,args,pid,ppid,pgid,etime,nice,rgroup,ruser,time,tty,vsz,stat,rss

And indeed, on my workstation the following work OK:
docker top [] a -o pid,user,group,comm,args,ppid,pgid,etime,nice,rgroup,ruser,time,tty,vsz,stat,rss

Don’t know how to get the CPU out of this then.

Docker for Mac ps info:
ps --version ps: unrecognized option: version BusyBox v1.24.1 (2015-12-16 08:00:02 GMT) multi-call binary.

7

So what’s the best way to file a bug and get that fixed? :confused:

8

Hi Matt,

I’ve opened internal issue #3491 to track this deficiency in docker top.

Thanks for your report and participation in the Docker for Mac Beta!

Best regards,

David

9

Great! Glad to hear it. Is there any idea of an ETA for a fix? Trying to determine if we should look at a work around on our end or just wait. :slight_smile: