The yaml configuration you posted for mounting volumes looks correct to me. For reference, you can see a sample yaml configuration that we use in our integration tests here [1]. I feel like you could definitively test whether or not drone is mounting the volume with the below pipeline:
kind: pipeline
type: kubernetes
name: default
steps:
- name: write
image: alpine
commands:
- echo "hello" > /root/.ivy2/greetings.txt
volumes:
- name: cache
path: /root/.ivy2
- name: read
image: alpine
commands:
- ls -la /root/.ivy2
- cat /root/.ivy2/greetings.txt
volumes:
- name: cache
path: /root/.ivy2
volumes:
- name: cache
host:
path: /opt/drone/cache
However, please note that the above mounts a host volume, not a persistent volume claim. I believe configuring a persistent volume claim requires different syntax than mounting a host volume.
[1] https://github.com/drone-runners/drone-runner-kube/blob/master/samples/volume_host.yml
If we configure the extra volume mounts in the drone server deployment, notice the same thing.
I’m not sure I fully understand, since the Drone server does not have any configuration options that relate to kubernetes or volume mounting.