Adding text collector for i40e VF stats from node

The stats are generated by divingbell job and node-exporter picks
the stats from the host file system.

Change-Id: I0f73a6f3ca7e9d045832435410933bd630a8c686

prometheus-node-exporter/templates/bin/_node-exporter.sh.tpl

@@ -20,4 +20,7 @@ set -ex
 exec /bin/node_exporter \
   {{ tuple "--collector." .Values.conf.collectors.enable | include "helm-toolkit.utils.joinListWithPrefix" }} \
   {{ tuple "--no-collector." .Values.conf.collectors.disable | include "helm-toolkit.utils.joinListWithPrefix" }} \
+  {{ if .Values.conf.collectors.textfile.directory }} \
+  --collector.textfile.directory={{.Values.conf.collectors.textfile.directory }} \
+  {{- end }}
   --collector.ntp.server={{ .Values.conf.ntp_server_ip }}

prometheus-node-exporter/templates/daemonset.yaml

@@ -88,6 +88,11 @@ spec:
             - name: sys
               mountPath: /host/sys
               readOnly:  true
+{{ if .Values.conf.collectors.textfile.directory }}
+            - name: stats-out
+              mountPath: {{.Values.conf.collectors.textfile.directory }}
+              readOnly:  true
+{{ end }}
             - name: node-exporter-bin
               mountPath: /tmp/node-exporter.sh
               subPath: node-exporter.sh
@@ -99,6 +104,11 @@ spec:
         - name: sys
           hostPath:
             path: /sys
+{{ if .Values.conf.collectors.textfile.directory }}
+        - name: stats-out
+          hostPath:
+            path: {{.Values.conf.collectors.textfile.directory }}
+{{ end }}
         - name: node-exporter-bin
           configMap:
             name: node-exporter-bin

prometheus-node-exporter/values.yaml

@@ -154,3 +154,5 @@ conf:
       - bonding
       - mountstats
     disable:
+    textfile:
+      directory: /var/log/node-exporter-vfstats