Kubernetes Node Distribution and Availability: Implementation and Testing Notes

Implementation notes

A Kubernetes clusters control plane must be distributed over multiple physical machines, as well as different "failure zones". How these are defined is at the moment up to the CSP. Worker nodes can also be distributed over "failure zones", but this isn't a requirement. Distribution must be shown through labelling, so that users can access these information.

Node distribution metadata is provided through the usage of the labels topology.kubernetes.io/region and topology.kubernetes.io/zone.

Automated tests

Currently, automated testing is not readily possible because we cannot access information about the underlying host of a node (as opposed to its region and zone). Therefore, the test will only output a tentative result.

The current implementation can be found in the script k8s_node_distribution_check.py.

Manual tests

None.