kubectl and the failing versions

from a Smoke Test running in Jenkins against a Kubernetes cluster.

In part, the Smoke Test uses kubectl to retrieve nodes, deployments and services.

Long story short, this was an issue of K8s versions.

There was a clue: -

My cluster is running K8s v1.16.2 whereas the version of kubectl is v1.18.6.

Therefore, there was a 2+ version mismatch between the two.

The problem was relatively simple ...

The Jenkins Pipeline was invoking a Bash script which was running kubectl from the path - which was picking up the default, latest version - v1.18.6 - whereas it should've been running it from the current directory ( via ./kubectl ).

Once I realised this, and remediated it, all was well .......