Document how to deploy to different regions and stack names

Highlight in documentation how to deploy and delete stacks that have
names and regions different from the default ones.

Change-Id: I81a4839aed4054bda2fcb52b06e0cbf5ac61f6fb
diff --git a/Configuration.md b/Configuration.md
index 5db9342..28efac2 100644
--- a/Configuration.md
+++ b/Configuration.md
@@ -15,6 +15,8 @@
 
 Configuration values affecting deployment environment and cluster properties
 
+* `AWS_REGION`: Optional. Which region to deploy to. `us-east-1` by default.
+* `AWS_PREFIX`: Optional. A string to prefix stacks and resources with. `gerrit` by default.
 * `DOCKER_REGISTRY_URI`: Mandatory. URI of the Docker registry. See the
   [prerequisites](Prerequisites.md) section for more details.
 * `SSL_CERTIFICATE_ARN`: Mandatory. ARN of the wildcard SSL Certificate, covering both master nodes.
diff --git a/dual-master/README.md b/dual-master/README.md
index d792651..f07b040 100644
--- a/dual-master/README.md
+++ b/dual-master/README.md
@@ -93,8 +93,11 @@
 * Create the cluster, services and DNS routing stacks:
 
 ```
-make create-all
+make [AWS_REGION=a-valid-aws-region] [AWS_PREFIX=some-cluster-prefix] create-all
 ```
+
+The optional `AWS_REGION` and `AWS_REFIX` allow you to define where it will be deployed and what it will be named.
+
 It might take several minutes to build the stack.
 You can monitor the creations of the stacks in [CloudFormation](https://console.aws.amazon.com/cloudformation/home)
 
@@ -106,9 +109,11 @@
 ### Cleaning up
 
 ```
-make delete-all
+make [AWS_REGION=a-valid-aws-region] [AWS_PREFIX=some-cluster-prefix] delete-all
 ```
 
+The optional `AWS_REGION` and `AWS_REFIX` allow you to specify exactly which stack you target for deletion.
+
 Note that this will *not* delete:
 * Secrets stored in Secret Manager
 * SSL certificates
diff --git a/master-slave/README.md b/master-slave/README.md
index efec40b..0f44bfa 100644
--- a/master-slave/README.md
+++ b/master-slave/README.md
@@ -86,9 +86,11 @@
 * Create the cluster, services and DNS routing stacks:
 
 ```
-make create-all
+make [AWS_REGION=a-valid-aws-region] [AWS_PREFIX=some-cluster-prefix] create-all
 ```
 
+The optional `AWS_REGION` and `AWS_REFIX` allow you to define where it will be deployed and what it will be named.
+
 It might take several minutes to build the stack.
 You can monitor the creations of the stacks in [CloudFormation](https://console.aws.amazon.com/cloudformation/home)
 
@@ -100,9 +102,10 @@
 ### Cleaning up
 
 ```
-make delete-all
+make [AWS_REGION=a-valid-aws-region] [AWS_PREFIX=some-cluster-prefix] delete-all
 ```
 
+The optional `AWS_REGION` and `AWS_REFIX` allow you to specify exactly which stack you target for deletion.
 
 Note that this will *not* delete:
 * Secrets stored in Secret Manager
diff --git a/single-master/README.md b/single-master/README.md
index 64175a9..216c910 100644
--- a/single-master/README.md
+++ b/single-master/README.md
@@ -77,9 +77,11 @@
 * Create the cluster, service and DNS routing stacks:
 
 ```
-make create-all
+make [AWS_REGION=a-valid-aws-region] [AWS_PREFIX=some-cluster-prefix] create-all
 ```
 
+The optional `AWS_REGION` and `AWS_REFIX` allow you to define where it will be deployed and what it will be named.
+
 It might take several minutes to build the stack.
 You can monitor the creations of the stacks in [CloudFormation](https://console.aws.amazon.com/cloudformation/home)
 
@@ -91,9 +93,11 @@
 ### Cleaning up
 
 ```
-make delete-all
+make [AWS_REGION=a-valid-aws-region] [AWS_PREFIX=some-cluster-prefix] delete-all
 ```
 
+The optional `AWS_REGION` and `AWS_REFIX` allow you to specify exactly which stack you target for deletion.
+
 Note that this will *not* delete:
 * Secrets stored in Secret Manager
 * SSL certificates