For a non-pipeline job, if I setup the build environment and try to set the Kubernetes server endpoint to an environment/build variable, e.g. either $K8S_URL or ${K8S_URL} , it is not interpolated and results in these failures, respectively:

Unable to connect to the server: dial tcp: lookup $K8S_URL: no such host

Unable to connect to the server: invalid character "{" in host name

For a pipeline job, I can just use env.K8S_URL and it works perfectly. Some of our job's steps do not support pipeline, and with multiple kubernetes clusters it would be very useful to have this functionality in a Freestyle job.