Prometheus: provide options to use existing PVCs (#252)

* Provide options to use existing PVCs

* Added persistentVolume.existingClaim options for alertmanager & server
* If defined, use those named PVCs. Else create new ones using template
* Documentation

* chart version bump

stable/prometheus/Chart.yaml

@@ -1,5 +1,5 @@
 name: prometheus
-version: 2.0.0
+version: 2.0.1
 description: A Prometheus Helm chart for Kubernetes. Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/
 sources:

stable/prometheus/README.md

@@ -54,6 +54,7 @@ The following tables lists the configurable parameters of the Prometheus chart a
 | `alertmanager.name` | Alertmanager container name | `alertmanager` |
 | `alertmanager.persistentVolume.enabled` | If true, AlertManager will create a Persistent Volume Claim | `true` |
 | `alertmanager.persistentVolume.accessModes` | AlertManager data Persistent Volume access modes | `[ReadWriteOnce]` |
+| `alertmanager.persistentVolume.existingClaim` | AlertManager data Persistent Volume existing claim name | |
 | `alertmanager.persistentVolume.size` | AlertManager data Persistent Volume size | `2Gi` |
 | `alertmanager.persistentVolume.storageClass` | AlertManager data Persistent Volume Storage Class | `volume.alpha.kubernetes.io/storage-class: default` |
 | `alertmanager.resources` | Alertmanager resource requests and limits (YAML) |`requests: {cpu: 10m, memory: 32Mi}` |
@@ -81,6 +82,7 @@ The following tables lists the configurable parameters of the Prometheus chart a
 | `server.persistentVolume.enabled` | If true, Server will create a Persistent Volume Claim | `false` |
 | `server.persistentVolume.accessModes` | Server data Persistent Volume access modes | `[ReadWriteOnce]` |
 | `server.persistentVolume.annotations` | Server data Persistent Volume annotations | `[]` |
+| `server.persistentVolume.existingClaim` | Server data Persistent Volume existing claim name | |
 | `server.persistentVolume.size` | Server data Persistent Volume size | `8Gi` |
 | `server.persistentVolume.storageClass` | Server data Persistent Volume Storage Class | `volume.alpha.kubernetes.io/storage-class: default` |
 | `server.resources` | Server resource requests and limits | `requests: {cpu: 500m, memory: 512Mi}` |

stable/prometheus/templates/alertmanager-deployment.yaml

@@ -56,7 +56,7 @@ spec:
         - name: storage-volume
       {{- if .Values.alertmanager.persistentVolume.enabled }}
           persistentVolumeClaim:
-            claimName: {{ template "alertmanager.fullname" . }}
+            claimName: {{ if .Values.alertmanager.persistentVolume.existingClaim }}{{ .Values.alertmanager.persistentVolume.existingClaim }}{{- else }}{{ template "alertmanager.fullname" . }}{{- end }}
       {{- else }}
           emptyDir: {}
       {{- end -}}

stable/prometheus/templates/alertmanager-pvc.yaml

@@ -1,4 +1,5 @@
 {{- if .Values.alertmanager.persistentVolume.enabled -}}
+{{- if not .Values.alertmanager.persistentVolume.existingClaim -}}
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:
@@ -27,3 +28,4 @@ spec:
     requests:
       storage: {{ .Values.alertmanager.persistentVolume.size | quote }}
 {{- end -}}
+{{- end -}}

stable/prometheus/templates/server-deployment.yaml

@@ -67,7 +67,7 @@ spec:
         - name: storage-volume
       {{- if .Values.server.persistentVolume.enabled }}
           persistentVolumeClaim:
-            claimName: {{ template "server.fullname" . }}
+            claimName: {{ if .Values.server.persistentVolume.existingClaim }}{{ .Values.server.persistentVolume.existingClaim }}{{- else }}{{ template "server.fullname" . }}{{- end }}
       {{- else }}
           emptyDir: {}
       {{- end -}}

stable/prometheus/templates/server-pvc.yaml

@@ -1,4 +1,5 @@
 {{- if .Values.server.persistentVolume.enabled -}}
+{{- if not .Values.server.persistentVolume.existingClaim -}}
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:
@@ -27,3 +28,4 @@ spec:
     requests:
       storage: {{ .Values.server.persistentVolume.size | quote }}
 {{- end -}}
+{{- end -}}

stable/prometheus/values.yaml

@@ -42,7 +42,7 @@ alertmanager:
   name: alertmanager
 
   persistentVolume:
-    ## If true, AlertManager will create a Persistent Volume Claim
+    ## If true, AlertManager will create/use a Persistent Volume Claim
     ## If false, use emptyDir
     ##
     enabled: true
@@ -58,6 +58,11 @@ alertmanager:
     ##
     # annotations:
 
+    ## AlertManager data Persistent Volume existing claim name
+    ## Requires alertmanager.persistentVolume.enabled: true
+    ## If defined, PVC must be created manually before volume will be bound
+    # existingClaim:
+
     ## AlertManager data Persistent Volume size
     ##
     size: 2Gi
@@ -192,7 +197,7 @@ server:
   name: server
 
   persistentVolume:
-    ## If true, Server will create a Persistent Volume Claim
+    ## If true, Server will create/use a Persistent Volume Claim
     ## If false, use emptyDir
     ##
     enabled: true
@@ -208,6 +213,11 @@ server:
     ##
     # annotations:
 
+    ## Server data Persistent Volume existing claim name
+    ## Requires server.persistentVolume.enabled: true
+    ## If defined, PVC must be created manually before volume will be bound
+    # existingClaim:
+
     ## Server data Persistent Volume size
     ##
     size: 8Gi