Adds Solr Scaler docs

content/docs/2.10/scalers/solr.md

@@ -0,0 +1,80 @@
++++
+title = "Solr"
+availability = "v2.10+"
+maintainer = "Community"
+description = "Scale applications based on Solr query results."
+go_file = "solr_scaler"
++++
+
+### Trigger Specification
+
+This specification describes the solr trigger that scales based on the outputs of a Solr query.
+
+```yaml
+triggers:
+  - type: solr
+    metadata:
+      host: "http://solr-service.solr-ns.svc.cluster.local:8983"
+      query: "*:*"
+      core: "my_core"
+      targetQueryValue: "1"
+      activationTargetQueryValue : "3"
+      username: "solr"
+```
+
+**Parameter list:**
+
+- `host` - The hostname for connecting to the Solr service.
+- `query`- A Solr query that should return single numeric value. (Default: `*:*`, Optional)
+- `core` - Your collection name on Solr.
+- `targetQueryValue` - A threshold that is used as targetValue or targetAverageValue (depending on the trigger metric type) in HPA. (This value can be a float)
+- `activationTargetQueryValue` - Target value for activating the scaler. Learn more about activation [here](./../concepts/scaling-deployments.md#activating-and-scaling-thresholds).(Default: `0`, Optional)
+- `username` - Username credential to connect to the Solr service.
+
+### Authentication Parameters
+
+You can authenticate by using a password via TriggerAuthentication configuration.
+
+**Credential based authentication:**
+
+- `password` - Password for configured user to login to the Solr instance.
+
+### Example
+
+```yaml
+apiVersion: v1
+kind: Secret
+metadata:
+  name: solr-secret
+type: Opaque
+data:
+  solr_password: SOLR_PASSWORD
+---
+apiVersion: keda.sh/v1alpha1
+kind: TriggerAuthentication
+metadata:
+  name: trigger-auth-solr
+spec:
+  secretTargetRef:
+  - parameter: password
+    name: solr-secret
+    key: solr_password
+---
+apiVersion: keda.sh/v1alpha1
+kind: ScaledObject
+metadata:
+  name: solr-scaledobject
+spec:
+  scaleTargetRef:
+    name: nginx-deploy        
+  triggers:
+  - type: solr
+    metadata:
+      host: "http://solr-service.solr-ns.svc.cluster.local:8983"
+      query: "*:*"
+      core: "my_core"
+      targetQueryValue: "1"
+      username: "solr"
+    authenticationRef:
+      name: trigger-auth-solr
+```