Well, thnx for the tip, but in my case it did not work out.
The agent fetches a lot of stuff but then failes with:
Traceback (most recent call last):
File "./agent_kubernetes", line 9, in <module>
sys.exit(main())
File "/omd/sites/ote/lib/python/cmk/special_agents/agent_kubernetes.py", line 1215, in main
api_data = ApiData(api_client)
File "/omd/sites/ote/lib/python/cmk/special_agents/agent_kubernetes.py", line 1007, in __init__
for node in nodes.items
File "/omd/sites/ote/local/lib/python/kubernetes/client/api/core_v1_api.py", line 1919, in connect_get_node_proxy_with_path
return self.connect_get_node_proxy_with_path_with_http_info(name, path, **kwargs) # noqa: E501
File "/omd/sites/ote/local/lib/python/kubernetes/client/api/core_v1_api.py", line 2020, in connect_get_node_proxy_with_path_with_http_info
collection_formats=collection_formats)
File "/omd/sites/ote/local/lib/python/kubernetes/client/api_client.py", line 353, in call_api
_preload_content, _request_timeout, _host)
File "/omd/sites/ote/local/lib/python/kubernetes/client/api_client.py", line 184, in __call_api
_request_timeout=_request_timeout)
File "/omd/sites/ote/local/lib/python/kubernetes/client/api_client.py", line 377, in request
headers=headers)
File "/omd/sites/ote/local/lib/python/kubernetes/client/rest.py", line 243, in GET
query_params=query_params)
File "/omd/sites/ote/local/lib/python/kubernetes/client/rest.py", line 233, in request
raise ApiException(http_resp=r)
kubernetes.client.exceptions.ApiException: (404)
I’m running kubernetes 1.19.
Update:
I forgot to add the --enable-cadvisor-json-endpoints flag in all nodes; just did it on the control-plane node. After I fixed it, it worked 
thnx a lot 
Update 2:
Now that the check retrives information, check_mk is not very happy with it, since it reports CRIT - [special_kubernetes] Version: unknown, OS: unknown, Got no information from host, execution time 28.5 sec … which also renders this agent not usable.