Update RHCOS image upload steps for GCP

Author: codyhoag

modules/installation-gcp-user-infra-rhcos.adoc

@@ -12,7 +12,7 @@ your {product-title} nodes.
 
 ifndef::openshift-origin[]
 . Obtain the {op-system} image from the
-link:https://mirror.openshift.com/pub/openshift-v4/dependencies/<opsystem/latest/[{op-system} image mirror]
+link:https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/latest/[{op-system} image mirror]
 page.
 +
 [IMPORTANT]
@@ -24,19 +24,34 @@ that matches your {product-title} version if it is available.
 ====
 +
 The file name contains the {product-title} version number in the format
-`rhcos-<version>-gcp.tar`.
+`rhcos-<version>-<arch>-gcp.<arch>.tar.gz`.
 endif::openshift-origin[]
 ifdef::openshift-origin[]
 . Obtain the {op-system} image from the
 link:https://getfedora.org/en/coreos/download?tab=cloud_operators&stream=stable[{op-system} Downloads] page
 endif::openshift-origin[]
 
-. Export the following variable:
+. Create the Google storage bucket:
 +
 [source,terminal]
 ----
-$ export IMAGE_SOURCE=<downloaded_image_file_path>
+$ gsutil mb gs://<bucket_name>
 ----
+
+. Upload the {op-system} image to the Google storage bucket:
++
+[source,terminal]
+----
+$ gsutil cp <downloaded_image_file_path>/rhcos-<version>-x86_64-gcp.x86_64.tar.gz  gs://<bucket_name>
+----
+
+. Export the uploaded {op-system} image location as a variable:
++
+[source,terminal]
+----
+$ export IMAGE_SOURCE=`gs://<bucket_name>/rhcos-<version>-x86_64-gcp.x86_64.tar.gz`
+----
+
 . Create the cluster image:
 +
 [source,terminal]