Bug 1291020 - no processes producing IO are listed when run in (privileged) docker container
no processes producing IO are listed when run in (privileged) docker container
Product: Fedora
Classification: Fedora
Component: iotop (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Adel Gadllah
Fedora Extras Quality Assurance
Depends On:
  Show dependency treegraph
Reported: 2015-12-12 16:36 EST by Chris Murphy
Modified: 2016-12-20 11:58 EST (History)
1 user (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2016-12-20 11:58:01 EST
Type: Bug
Regression: ---
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Documentation: ---
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
strace iotop -d3 (162.52 KB, text/plain)
2015-12-12 16:38 EST, Chris Murphy
no flags Details
iotop screenshot (33.42 KB, image/png)
2015-12-12 16:42 EST, Chris Murphy
no flags Details

  None (edit)
Description Chris Murphy 2015-12-12 16:36:19 EST
Description of problem:

When running iotop in a privileged docker container, it doesn't list any processes that are producing reads and/or writes to disk.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. System is based on Fedora-Cloud_Atomic-x86_64-23.iso, with tree 23.29 deployed.
2. On host, btrfs check <dev>, and also btrfs scrub start. So there should be at least one btrfs process running with the attached strace, producing IO.
2. docker run --net=host -v /dev:/dev --privileged=true -it fedext /usr/sbin/iotop -d3

Actual results:

No processes listed, see screen shot which shows there is read IO happening, but no processes are listed. 

Expected results:

When run outside of docker the process listing without -o is rather lengthy, but this has only two processes neither of which are btrfs user space tool doing the check or scrub.

I expect the same behavior in docker.

Additional info:

Started out here when it was crashing in docker, bug --net=host
Comment 1 Chris Murphy 2015-12-12 16:38 EST
Created attachment 1105172 [details]
strace iotop -d3

The result of 'strace iotop -d' inside a docker container run with command 'docker run --net=host -v /dev:/dev --privileged=true -it fedext /bin/bash' while the host was running 'btrfs check /dev/sda' and producing a bunch of read IO.
Comment 2 Chris Murphy 2015-12-12 16:42 EST
Created attachment 1105173 [details]
iotop screenshot

This is a screenshot of what I see with 'iotop -d3' when run in the privileged docker container.

Notice a textUI anomaly that's weird: the 3rd row (black text on white), between the SWAPIN and COMMAND columns is this phantom IO> text. This phantom text doesn't appear when the command is run outside of a container.
Comment 3 Fedora End Of Life 2016-11-24 09:12:00 EST
This message is a reminder that Fedora 23 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 23. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '23'.

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Comment 4 Fedora End Of Life 2016-12-20 11:58:01 EST
Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

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