NRPE plugin issue after 5.5.0 upgrade (still in 5.5.1)

[macranes]

After upgrading our Nagios XI instance to 5.5.0 we have started getting errors on a number of our plugins on windows servers. The error reported through Nagios XI is:

Could not construct return paket in NRPE handler check clientside (nsclient.log) logs

I have checked on the client servers, and although we have logging enabled through our nsclient.ini file there is no nsclient.log file generated on that system for additional debugging:

[log]
;# LOG DEBUG
; Set to 1 if you want debug message printed in the log file (debug messages are always printed to stdout when run with -test)
debug=1
;
;# LOG FILE
; The file to print log statements to
file=nsclient.log

This morning I upgraded to 5.5.1, but the issue still persists there.

As best I can tell we are running NSClient++ (x64) 0.3.8 (although if someone knows how to get the version information from the binary I'd appreciate it), and this is affecting plugins that call powershell scripts. Here is an example line from the [Extenal Scripts] portion:

read_file_E=cmd /c echo scripts\read_file_E.ps1; exit($lastexitcode) | powershell.exe -command -

This was working under 5.4.x through a number of upgrades, but the upgrade to 5.5 has started responding this way. I'm relatively certain that it's not on the client side, as the only change in this process was upgrading our Nagios XI monitoring server. We did a yum update on CentOS at the same time - but I'm looking at Nagios right now, as that's where our error is generating.

Thank you for your time. Any assistance would be appreciated. Please let me know if there is other information I could provide that would be helpful.

[jomann]

I think that the older versions of NSClient++ are not working nicely with the new version of NRPE 3 instead of NRPE 2. What you can do, which is slightly time consuming, is test the -2 option on the check_nrpe command line on some of your checks and see if that solves the issue. If it does, I would recommend creating a new legacy check_nrpe2 command in the CCM and using that for your systems that don't play nicely with the new NRPE version.

[macranes]

Thank you! I've just tested three of our plugins, but his seems to be solving the issue. I will get through the rest of them tomorrow, but it looks like this will address all of our various services.

[jomann]

Great, if you have any other problems let us know.