WIP

README.md

@@ -415,6 +415,15 @@ spec:
       weight: ...
     - arn: ...
       weight: ...
+status:
+  listenerARN: ...
+  forwardConfig:
+    priority: 10
+    targetGroups:
+    - arn: ...
+      weight: ...
+    - arn: ...
+      weight: ...
 ```
 
 `system-controller` uses either `targetgroupBindingSelector: svc=web` or `arnFromLabel: targetGroupARN` that is available in the embedded `alb` spec to determine the ARN of the target group for each cluster, and places those ARNs under `ALB.spec.forwardConfig.targetGroups`.
@@ -423,6 +432,8 @@ Then, `system-controller` gradually updates `alb.spec.forwardConfig.targetGroups
 
 `alb-controller` reconciles `ALB` resources by calling AWS APIs to update ALB Listener Rules.
 
+`ALB`'s `status` sub-resource contains all the fields of the `spec` that applied to AWS. `system-controller` compares `alb.spec` and `alb.status` and move the process forward only after the two becomes in-sync. Otherwise, it might fail to update weights by `stepWeight` when in a temporary AWS failure.
+
 ### `Check`
 
 ```