chore(prometheus): Expose prometheus configuration options in Scale GUI (#3797)

* Update prometheus configuration

* Add new config quesiton to adjust prometheus.scrapeInterval.
* Add new config question to adjust prometheus.evaluationInterval.
* Set default scrapeInterval to 15s to match typical Prometheus
  deployments.
* Set WAL compression to on by default, this has been default upstream
  since Prometheus v2.20.0 (2020-07-22).

Signed-off-by: SuperQ <superq@gmail.com>

* Update charts/stable/prometheus/questions.yaml

Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>

Signed-off-by: SuperQ <superq@gmail.com>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Co-authored-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>

charts/stable/prometheus/Chart.yaml

@@ -29,7 +29,7 @@ sources:
   - https://github.com/prometheus-community/helm-charts
   - https://github.com/prometheus-operator/kube-prometheus
 type: application
-version: 4.0.84
+version: 4.0.85
 annotations:
   truecharts.org/catagories: |
     - metrics

charts/stable/prometheus/questions.yaml

@@ -55,6 +55,18 @@ questions:
                 schema:
                   type: string
                   default: ""
+              - variable: scrapeInterval
+                label: "Scrape interval"
+                description: "Interval between consecutive scrapes"
+                schema:
+                  type: string
+                  default: "15s"
+              - variable: evaluationInterval
+                label: "Evaluation interval"
+                description: "Interval between consecutive evaluations"
+                schema:
+                  type: string
+                  default: "30s"
               - variable: disableCompaction
                 label: "Disable Compaction"
                 description: "Disable the compaction of the Prometheus TSDB"
@@ -67,6 +79,7 @@ questions:
                 schema:
                   type: boolean
                   default: false
+
   - variable: alertmanager
     group: "App Configuration"
     label: "Alertmanager Settings"

charts/stable/prometheus/values.yaml

@@ -404,10 +404,10 @@ prometheus:
   tolerations: []
   ## @param prometheus.scrapeInterval Interval between consecutive scrapes
   ##
-  scrapeInterval: ""
+  scrapeInterval: "15s"
   ## @param prometheus.evaluationInterval Interval between consecutive evaluations
   ##
-  evaluationInterval: ""
+  evaluationInterval: "30s"
   ## @param prometheus.listenLocal ListenLocal makes the Prometheus server listen on loopback
   ##
   listenLocal: false