home-assistant: Manage YAML files with ConfigMap

Editing `configuration.yaml` et al. using `vi` via `kubectl exec` is
rather tedious, since the version of `vi` in the *home-assistant*
container image is very rudimentary.  Thus, I think it would be better
to use a ConfigMap to store the manually-edited YAML files, so I can
edit them with my regular editor on my desktop.  For this to work, the
ConfigMap has to be mounted as a directory rather than as individual
files (using `subPath`), as otherwise the pod would have to be restarted
every time one of the files is updated.

home-assistant/kustomization.yaml

@@ -20,6 +20,18 @@ resources:
 - ingress.yaml
 
 configMapGenerator:
+- name: home-assistant
+  files:
+  - configuration.yaml
+  - groups.yaml
+  - shell-command.yaml
+  options:
+    disableNameSuffixHash: true
+    labels:
+      app.kubernetes.io/name: home-assistant
+      app.kubernetes.io/component: home-assistant
+      app.kubernetes.io/part-of: home-assistant
+
 - name: mosquitto
   files:
   - mosquitto.conf
@@ -48,3 +60,19 @@ patches:
                   key: username
             - name: RECORDER_DB_URL
               value: postgresql://$(RECORDER_DB_USERNAME):$(RECORDER_DB_PASSWORD)@default.postgresql/homeassistant
+            volumeMounts:
+            - mountPath: /run/config
+              name: home-assistant-config
+              readOnly: true
+            - mountPath: /run/secrets/home-assistant
+              name: home-assistant-secrets
+              readOnly: true
+          volumes:
+          - name: home-assistant-config
+            configMap:
+              name: home-assistant
+              defaultMode: 0600
+          - name: home-assistant-secrets
+            secret:
+              secretName: home-assistant
+              defaultMode: 0640