Kata container runtime logs needs own file

[Brent Rowsell]

Brief Description
-----------------
Kata container runtime logs are currently going to kern.log. This is incorrect, only the host kernel logs should be going there. The kata runtime logs should be going to a separate file setup with logs rotation. Example

2020-02-23T17:53:38.000 controller-0 kata[1857644]: warning time="2020-02-23T17:53:38.019295983Z" level=warning msg="sandbox's cgroup won't be updated: cgroup path is empty" ID=30d3bd8f6a70c057f9df7e667129375d6ca1b6d75bd9ac9b7bd75b1605a2118f sandbox=30d3bd8f6a70c057f9df7e667129375d6ca1b6d75bd9ac9b7bd75b1605a2118f source=virtcontainers subsystem=sandbox
2020-02-23T17:53:48.000 controller-0 kata[1857644]: warning time="2020-02-23T17:53:48.326678792Z" level=warning msg="Cannot hotplug 1 CPUs, currently this SB has 2 CPUs and the maximum amount of CPUs is 2" ID=30d3bd8f6a70c057f9df7e667129375d6ca1b6d75bd9ac9b7bd75b1605a2118f source=virtcontainers subsystem=qemu

Severity
--------
Major

Steps to Reproduce
------------------
Launch a container with kata runtime

Expected Behavior
------------------
No kata runtime logs in kern.log

Actual Behavior
----------------
Kata runtime logs in kern.log

Reproducibility
---------------
100%

System Configuration
--------------------
All

Branch/Pull Time/Commit
-----------------------
BUILD_DATE="2020-02-22 04:15:31 -0500"

Last Pass
---------
Never

Timestamp/Logs
--------------
See above

Test Activity
-------------
Developer testing

Workaround
----------
None

[Ghada Khalil (gkhalil)]

stx.4.0 / medium priority - impacts debuggability

Unsure if this is related to the upstream kata container project or specific to the StarlingX config

[Ghada Khalil (gkhalil)]

Assigning to the Kata Containers Feature Prime

[Lin Shuicheng (shuicheng)]

I checked kata config file. It seems it cannot configure the output log file.
I will check it further.

[Lin Shuicheng (shuicheng)]

Currently, kata will always output log to kern.log. With default setting, kata will output waning/error message only to kern.log.
There is no configuration we could disable it or configure it currently.

Here is the words from kata:
https://github.com/kata-containers/runtime#kata-containerd-shimv2
"
Kata containerd shimv2
The Kata containerd shimv2 runtime logs through containerd, and its logs will be sent to wherever the containerd logs are directed. However, the shimv2 runtime also always logs to the system log (syslog or journald) under the identifier name of kata.
"

[Brent Rowsell (brent-rowsell)]

SO what is the plan to address this LP ?

[Lin Shuicheng (shuicheng)]

I prefer to keep kata log in kern.log.
What is the issue with it?

[Ghada Khalil (gkhalil)]

Lowering the priority as it appears there is no mechanism to do this in kata