Launching tests in containers on Kubernetes
Based on information you provided all I can recomend is kubernetes API itself.
You can create a pod with it, wait for it to finish and gather logs. If thats all you need, you don't need any other fancy applications. Here is a list of k8s client libraries.
If you don't want to use client libraries you can always use REST api.
If you are not sure how to use REST api, run kubectl commands with --v=10 flag for debug output where you can see all requests between kubectl and api-server as a reference guide.
Kubernetes also provided detailed documentation for k8s REST api.
Try looking at https://microk8s.io/, it was built for those purposes.
And you can talk to the API server via the rest API same as in every k8s cluster.