Mounting a hostPath persistent volume to an Argo Workflow task template - kubernetes

Question

I am working on a small proof-of-concept project for my company and would like to use Argo Workflows to automate some data engineering tasks. It's really easy to get set up and I've been able to create a number of workflows that process data that is stored in a Docker image or is retrieved from a REST API. However, to work with our sensitive data I would like to mount a hostPath persistent volume to one of my workflow tasks. When I follow the documentation I don't get the desired behavior, the directory appears empty.
OS: Ubuntu 18.04.4 LTS
Kubernetes executor: Minikube v1.20.0
Kubernetes version: v1.20.2
Argo Workflows version: v3.1.0-rc4
My persistent volume (claim) looks like this:
apiVersion: v1
kind: PersistentVolume
metadata:
name: argo-volume
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 10Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/tmp/data"
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: argo-hello
spec:
storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
and I run
kubectl -n argo apply -f pv.yaml
My workflow looks as follows:
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
generateName: hello-world-volumes-
spec:
entrypoint: dag-template
arguments:
parameters:
- name: file
value: /mnt/vol/test.txt
volumes:
- name: datadir
persistentVolumeClaim:
claimName: argo-hello
templates:
- name: dag-template
inputs:
parameters:
- name: file
dag:
tasks:
- name: readFile
arguments:
parameters: [{name: path, value: "{{inputs.parameters.file}}"}]
template: read-file-template
- name: print-message
template: helloargo
arguments:
parameters: [{name: msg, value: "{{tasks.readFile.outputs.result}}"}]
dependencies: [readFile]
- name: helloargo
inputs:
parameters:
- name: msg
container:
image: lambertsbennett/helloargo
args: ["-msg", "{{inputs.parameters.msg}}"]
- name: read-file-template
inputs:
parameters:
- name: path
container:
image: alpine:latest
command: [sh, -c]
args: ["find /mnt/vol; ls -a /mnt/vol"]
volumeMounts:
- name: datadir
mountPath: /mnt/vol
When this workflow executes it just prints an empty directory even though I populated the host directory with files. Is there something I am fundamentally missing? Thanks for any help.