pre-release WLO 1.5.0 - dmesg.out in linperf_RESULTS archive file has read kernel buffer failed

[tam512]

Use WLO 1.5.0 to get WebSphereLibertyPerformanceData.
Extract the linperf_RESULTS.xxx.xxx.tar.gz file and I see the dmesg.out file has the following content

dmesg: read kernel buffer failed: Operation not permitted

Maybe we are missing certain privilege or capability, if so please specify what other configurations we need to configure before getting the performance data

[leochr]

@tam512 CAP_SYSLOG seems to be the capability needed to run the dmesg operation (as per this page). I am not entirely sure that the non-root user can gain permission to run the dmesg command, but worth a try.

I think the CAP_ portion is typically dropped from SCC and securityContext settings. Please add the following (in addition to any other settings you already have) and try. The snippets below only include the new capability that needs to be added:

1. Add SYSLOG to the custom SCC instance used by the Liberty app instance:

defaultAddCapabilities:
- SYSLOG

2. Add SYSLOG to .spec.securityContext in WebSphereLibertyApplication CR:

  securityContext:
    capabilities:
      add:
      - SYSLOG

If SYSLOG doesn't work, then please replace it with CAP_SYSLOG above and try again. If this works and generates the data, then we'll document so that users are aware of the capability, should they wish to generate this data as part of performance data. Thank you.

[tam512]

I'm on EKS and I do not know what is the default SecurityContextConstraints to add the new SYSLOG to it

% kubectl get SecurityContextConstraints -A
error: the server doesn't have a resource type "SecurityContextConstraints"

So I tried adding to the WebSphereLibertyApplication CR with SYSLOG and CAP_SYSLOG and I still see dmesg: read kernel buffer failed: Operation not permitted

• test 1

  securityContext:
    capabilities:
      add:
      - SYSLOG

then test2

  securityContext:
    capabilities:
      add:
      - CAP_SYSLOG