chart: move autofs root to hostPath

This commit makes it so that the nodeplugin shares its internal
/cvmfs autofs root via a hostPath instead of an emptyDir.

kubelet periodically scrapes metrics from all emptyDir volumes by
walking trough them recursively, stat()-ing each item. This however
resets the autofs mount expiry timeout, making it impossible to
automatically unmount unused CVMFS repos. The workaround for this is
to share /cvmfs via a hostPath which is not included by the metrics,
avoiding the issue.

Author: gman0

deployments/helm/README.md

@@ -102,6 +102,7 @@ Alternatively, a YAML file that specifies the values of the parameters can be pr
 | `kubeletDirectory` | Kubelet's plugin directory path.                                                                                                                 |
 | `cvmfsCSIPluginSocketFile` | Name of the CVMFS CSI socket file.                                                                                                       |
 | `startAutomountDaemon` | Whether CVMFS CSI nodeplugin Pod should run automount daemon.                                                                                |
+| `automountHostPath` | Path on the host where to mount the autofs-managed CVMFS root. The directory will be created if it doesn't exist.                               |
 | `automountStorageClass.create` | Whether a CVMFS CSI storage class using the automounter should be created automatically.                                             |
 | `automountStorageClass.name` | The name for the CVMFS CSI storage class using the automounter if created.                                                             |
 | `specificRepositoryStorageClasses` | A list of specific CVMFS repos you wish to generate a `storageClass` for.                                                        |

deployments/helm/cvmfs-csi/templates/nodeplugin-daemonset.yaml

@@ -82,9 +82,12 @@ spec:
               readOnly: true
             - name: host-dev
               mountPath: /dev
-            - name: autofs-cvmfs
+            - name: autofs-root
               mountPath: /cvmfs
               mountPropagation: Bidirectional
+            {{- with .Values.nodeplugin.plugin.extraVolumeMounts }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           {{- with .Values.nodeplugin.plugin.resources }}
           resources: {{ toYaml . | nindent 12 }}
           {{- end }}
@@ -113,7 +116,7 @@ spec:
               readOnly: true
             - name: host-dev
               mountPath: /dev
-            - name: autofs-cvmfs
+            - name: autofs-root
               mountPath: /cvmfs
               mountPropagation: Bidirectional
             - name: cvmfs-localcache
@@ -191,10 +194,12 @@ spec:
         - name: host-dev
           hostPath:
             path: /dev
-        - name: autofs-cvmfs
-          emptyDir: {}
         - name: runtime-metadata
           emptyDir: {}
+        - name: autofs-root
+          hostPath:
+            path: {{ .Values.automountHostPath }}
+            type: DirectoryOrCreate
         - name: cvmfs-localcache
           {{- toYaml .Values.cache.local.volumeSpec | nindent 10 }}
         {{- if .Values.cache.alien.enabled }}

deployments/helm/cvmfs-csi/values.yaml

@@ -234,6 +234,10 @@ kubeletDirectory: /var/lib/kubelet
 # <kubeletPluginDirectory>/plugins/<csiDriverName>/<cvmfsCSIPluginSocketFile>.
 cvmfsCSIPluginSocketFile: csi.sock
 
+# Path on the host where to mount the autofs-managed CVMFS root.
+# The directory will be created if it doesn't exist.
+automountHostPath: /var/cvmfs
+
 # Number of seconds to wait for automount daemon to start up before exiting.
 automountDaemonStartupTimeout: 10
 # Number of seconds of idle time after which an autofs-managed CVMFS mount will