Small clarification

The template for ingress-controller has a name already defined. If you already has your subnets tagged with a different cluster-name, you will find the error "retrieval of subnets failed to resolve 2 qualified subnet" and it's not clear why. This clarification in the docs may help.

Author: gonfva

docs/guide/controller/config.md

@@ -82,11 +82,11 @@ spec:
 ## Subnet Auto Discovery
 You can tag AWS subnets to allow ingress controller auto discover subnets used for ALBs.
 
-- `kubernetes.io/cluster/${cluster-name}` must be set to `owned` or `shared`
+- `kubernetes.io/cluster/${cluster-name}` must be set to `owned` or `shared`. Remember `${cluster-name}` needs to be the same name you're passing to the controller in the `--cluster-name` option
 
 - `kubernetes.io/role/internal-elb` must be set to `1` or `` for internal LoadBalancers
 
 - `kubernetes.io/role/elb` must be set to `1` or `` for internet-facing LoadBalancers
 
 An example of a subnet with the correct tags for the cluster `joshcalico` is as follows:
-![subnet-tags](../../imgs/subnet-tags.png)
+![subnet-tags](../../imgs/subnet-tags.png)