This ticket will unfortunately be a bit devoid of information, because I wasn't sure how to debug the problem and I didn't want to leave the tool broken.
I followed the instructions here, first for "earwigbot" as a test which worked well, then for "copyvios" which failed.
After running webservice start, webservice status reported "Your webservice of type python2 is running" but https://tools.wmflabs.org/copyvios/ returned 503s. kubectl get pods reported "No resources found", as did k8s-status, which showed the service/deployment but with no pods and with the "None/None" under Ready for the deployment. I gave it several minutes (~8) in case it was struggling to allocate resources but nothing changed. I then tried webservice restart which informed me "Your job is not running, starting", contrary to webservice status, but this did not change anything.
I had originally attempted webservice start with overridden limits to see how it would perform (--cpu 1 --mem 4), but thinking these might be the problem, I tried it again without those and it still did not work.
I've now migrated back to the old cluster and the tool is back to working.