Add docs and fix samples

Author: dmvolod

docs/administrator.md

@@ -706,6 +706,35 @@ data:
 The key-value pairs of the Secret are all accessible as environment variables
 to the Postgres StatefulSet/pods.
 
+### For individual cluster
+
+It is possible to set environment variables in the Spilo pods directly as parameters or
+as a link to secrets for each individual cluster, in addition to or instead of the
+global parameters given in the examples above.
+
+In order to do this, you need to configure the cluster parameters, as in the example below
+
+```yaml
+apiVersion: "acid.zalan.do/v1"
+kind: postgresql
+metadata:
+  name: acid-test-cluster
+spec:
+  env:
+  - name: wal_s3_bucket
+    value: my-custom-bucket
+  - name: minio_secret_key
+      valueFrom:
+        secretKeyRef:
+          name: my-custom-secret
+          key: minio_secret_key
+```
+
+If global parameters are set at the level of the entire controller in the form of
+a ConfigMap or a Secret, then the individual cluster parameters will have a higher
+priority and the same keys will be overridden, and different ones will be merged into
+a single array of environment variable parameter values.
+
 ## Limiting the number of min and max instances in clusters
 
 As a preventive measure, one can restrict the minimum and the maximum number of

manifests/complete-postgres-manifest.yaml

@@ -49,6 +49,10 @@ spec:
       shared_buffers: "32MB"
       max_connections: "10"
       log_statement: "all"
+#  env:
+#  - name: wal_s3_bucket
+#    value: my-custom-bucket
+
   volume:
     size: 1Gi
 #    storageClass: my-sc
@@ -120,7 +124,7 @@ spec:
 #        database: foo
 #        plugin: pgoutput
     ttl: 30
-    loop_wait: &loop_wait 10
+    loop_wait: 10
     retry_timeout: 10
     synchronous_mode: false
     synchronous_mode_strict: false