readme: describe mapping between operatorLogLevel and log level

Author: lance5890

README.md

@@ -78,6 +78,42 @@ Currently the log levels correspond to:
 | Trace    | 6         |
 | TraceAll | 10        |
 
+
+The log level of cluster-kube-controller-manager-operator can be increased by setting `.spec.operatorLogLevel` field:
+```
+$ oc explain KubeControllerManager.spec.operatorLogLevel
+GROUP:      operator.openshift.io
+KIND:       KubeControllerManager
+VERSION:    v1
+FIELD: operatorLogLevel <string>
+DESCRIPTION:
+    operatorLogLevel is an intent based logging for the operator itself.  It
+    does not give fine grained control, but it is a simple way to manage coarse
+    grained logging choices that operators have to interpret for themselves. 
+     Valid values are: "Normal", "Debug", "Trace", "TraceAll". Defaults to
+    "Normal".
+```
+For example:
+```yaml
+apiVersion: operator.openshift.io/v1
+kind: KubeControllerManager
+metadata:
+  name: cluster
+spec:
+  operatorLogLevel: Debug
+  ...
+```
+
+Currently the operator log levels correspond to:
+
+| logLevel | log level |
+| -------- | --------- |
+| Normal   | 2         |
+| Debug    | 4         |
+| Trace    | 6         |
+| TraceAll | 8         |
+
+
 ```
 $ oc explain kubecontrollermanager
 ```