Vital Readme updates.

base-image-builder/README.md

@@ -11,30 +11,45 @@ The builder also adds the [packer builder](https://github.com/GoogleCloudPlatfor
 * PACKER_SPEC the path to the Packer specification in the workspace (passed in as a [substitution with GCB](https://cloud.google.com/cloud-build/docs/configuring-builds/substitute-variable-values#using_user-defined_substitutions))
 
 
-## Create the Builder
+## Setup the Cloud Build service account
+```
+PROJECT=$(gcloud config get-value project)
+GCB_SA=$(gcloud projects get-iam-policy $PROJECT --filter="(bindings.role:roles/cloudbuild.builds.builder)"  --flatten="bindings[].members" --format="value(bindings.members[])")
+gcloud projects add-iam-policy-binding $PROJECT \
+  --member $GCB_SA --role roles/compute.instanceAdmin.v1
+ gcloud projects add-iam-policy-binding $PROJECT \
+  --member $GCB_SA --role roles/iam.serviceAccountUser
+```
+
+## Create the base-image-builder
 
 Run this build step and it will:
 
 1. Create a **packer** container image in your GCP Project GCR (later used as a build step)
-2. Create a custom GCE image with Nested Virtualization Enabled
-3. Create a Packer Agent with **packer** installed and Nested Virtualization Enabled
-4. Create a **build-image-builder** container image in your GCP Project GCR
+2. Create a custom GCE image with nested virtualization enabled
+3. Create a Packer Agent with **packer** installed and nested virtualization enabled
+4. Create a **base-image-builder** container image in your GCP Project GCR
 
 ```
-$ git clone git@github.com:GoogleCloudPlatform/cloud-builders-community
+$ git clone https://github.com:GoogleCloudPlatform/cloud-builders-community
 $ cd cloud-builders-community/base-image-builder
 $ gcloud builds submit .
 # or pass in custom substitutions
 $ export ZONE=us-central1-c
-$ gcloud builds submit . --substitutions "_IMAGE_ZONE=$ZONE,_BUILD_PACKER_AGENT_IMAGE=false,_BUILD_NESTED_VIRT_IMAGE=false"
+$ gcloud builds submit . --substitutions "_IMAGE_ZONE=$ZONE,_BUILD_PACKER_AGENT_IMAGE=true,_BUILD_NESTED_VIRT_IMAGE=true"
+```
+
+## Create a storage bucket for uploading your custom images
+```
+gsutil mb gs://$PROJECT-custom-images 
 ```
 
-## Use the Builder to Create a custom GCE image
+## Use the base-image-builder to create a custom GCE image
 
 After the builder is successfully built (with the above steps), you can use it to build custom images from an ISO:
 
 ```
-$ git clone git@github.com:GoogleCloudPlatform/compute-custom-boot-images
+$ git clone https://github.com/GoogleCloudPlatform/compute-custom-boot-images
 $ cd compute-custom-boot-images
 $ gcloud builds submit . --config cloudbuild/custom-boot-image-build.yaml
 ```