ability to opt-out persistent volume claim for trivy-server (#1457)

* ability to opt-out persistent volume claim for trivy-server

* updated docs with "make generate-helm-docs"

* fix lint [trailing-spaces]

deploy/helm/README.md

@@ -136,7 +136,8 @@ Keeps security report resources updated
 | trivy.skipJavaDBUpdate | bool | `false` | skipJavaDBUpdate is the flag to enable skip Java index databases update for Trivy client. |
 | trivy.slow | bool | `true` | slow this flag is to use less CPU/memory for scanning though it takes more time than normal scanning. It fits small-footprint |
 | trivy.sslCertDir | string | `nil` | sslCertDir can be used to override the system default locations for SSL certificate files directory, example: /ssl/certs |
-| trivy.storageClassName | string | `""` | storageClassName is the name of the storage class to be used for trivy server PVC |
+| trivy.storageClassEnabled | bool | `true` | whether to use a storage class for trivy server or emptydir (one mey want to use ephemeral storage) |
+| trivy.storageClassName | string | `""` | storageClassName is the name of the storage class to be used for trivy server PVC. If empty, tries to find default storage class |
 | trivy.supportedConfigAuditKinds | string | `"Workload,Service,Role,ClusterRole,NetworkPolicy,Ingress,LimitRange,ResourceQuota"` | The Flag is the list of supported kinds separated by comma delimiter to be scanned by the config audit scanner  |
 | trivy.timeout | string | `"5m0s"` | timeout is the duration to wait for scan completion. |
 | trivy.useBuiltinRegoPolicies | string | `"true"` | The Flag to enable the usage of builtin rego policies by default  |

deploy/helm/templates/trivy-server.yaml

@@ -35,6 +35,7 @@ spec:
     matchLabels:
       app.kubernetes.io/name: trivy-server
       app.kubernetes.io/instance: trivy-server
+  {{- if .Values.trivy.storageClassEnabled }}
   volumeClaimTemplates:
     - apiVersion: v1
       kind: PersistentVolumeClaim
@@ -47,6 +48,7 @@ spec:
         accessModes:
           - ReadWriteOnce
         storageClassName: {{ .Values.trivy.storageClassName }}
+  {{- end }}        
   template:
     metadata:
       annotations:
@@ -133,6 +135,10 @@ spec:
       volumes:
         - name: tmp-data
           emptyDir: {}
+        {{- if not .Values.trivy.storageClassEnabled }}
+        - name: data
+          emptyDir: {}
+        {{- end }}
       {{- with .Values.tolerations }}
       tolerations: {{- toYaml . | nindent 8 }}
       {{- end }}

deploy/helm/values.yaml

@@ -266,7 +266,10 @@ trivy:
   # on the active mode other settings might be applicable or required.
   mode: Standalone
 
-  # -- storageClassName is the name of the storage class to be used for trivy server PVC
+  # -- whether to use a storage class for trivy server or emptydir (one mey want to use ephemeral storage)
+  storageClassEnabled: true
+
+  # -- storageClassName is the name of the storage class to be used for trivy server PVC. If empty, tries to find default storage class
   storageClassName: ""
 
   # -- podLabels is the extra pod labels to be used for trivy server