Erroneous collecting "clusterversion" In case of openshift distribution

[ratsuf]

Good day!
I've tried to deploy Cerberus with distribution config "openshift" and faced the following issue:

2021-05-05 14:24:45,635 [INFO] Starting ceberus
2021-05-05 14:24:45,680 [INFO] Initializing client to talk to the Kubernetes cluster
2021-05-05 14:24:46,831 [INFO] Fetching cluster info
error: the server doesn't have a resource type "clusterversion"
2021-05-05 14:24:49,757 [ERROR] Failed to run kubectl get clusterversion
               _                         
  ___ ___ _ __| |__   ___ _ __ _   _ ___ 
 / __/ _ \ '__| '_ \ / _ \ '__| | | / __|
| (_|  __/ |  | |_) |  __/ |  | |_| \__ \
 \___\___|_|  |_.__/ \___|_|   \__,_|___/
                                         

Traceback (most recent call last):
  File "start_cerberus.py", line 468, in <module>
    main(options.cfg)
  File "start_cerberus.py", line 106, in main
    cluster_version = runcommand.invoke("kubectl get clusterversion")
  File "/root/cerberus/cerberus/invoke/command.py", line 12, in invoke
    return output
UnboundLocalError: local variable 'output' referenced before assignment

Could you please clarify for what purpose start_cerberus.py tries to get some resource with the name clusterversion using kubectl?
https://github.com/cloud-bulldozer/cerberus/blob/eb449aae83f9b331d76c4413d0b6f8ab020e0ee7/start_cerberus.py#L107-L109

Unfortunately, I cannot find any details about the command kubectl get clusterversion and the resource clusterversion.

As a temporary solution, I just switched off this if statement.

[chaitanyaenr]

Hi @ratsuf, thanks for reporting the issue. Think the older kubectl versions doesn't support getting the details of the resource clusterversion. We might want to update the kubectl version and see if it fixes it. On the other hand, I think we can switch it to use oc version since this operation is specific to openshift distribution.

[ratsuf]

Hi @chaitanyaenr!
Thank you for the reply.
Switching to oc version makes more sense in the context of openshift distribution from my point of view.

[chaitanyaenr]

@ratsuf Do you want to submit a patch for it?

[seanogor]

as above, tested commands on a mac #135

[ratsuf]

Dear @chaitanyaenr and @seanogor,
I'm afraid 'clusterversion' not present in OKD 3.11 and lower. Please considerate #137 as an extended version of #135 to fix the issue.