diff --git a/cluster/aws/util.sh b/cluster/aws/util.sh
index 0ec86ddb3de..874088271bb 100755
--- a/cluster/aws/util.sh
+++ b/cluster/aws/util.sh
@@ -120,10 +120,17 @@ NODE_SG_NAME="kubernetes-minion-${CLUSTER_ID}"
 # Be sure to map all the ephemeral drives.  We can specify more than we actually have.
 # TODO: Actually mount the correct number (especially if we have more), though this is non-trivial, and
 #  only affects the big storage instance types, which aren't a typical use case right now.
-BLOCK_DEVICE_MAPPINGS_BASE="{\"DeviceName\": \"/dev/sdc\",\"VirtualName\":\"ephemeral0\"},{\"DeviceName\": \"/dev/sdd\",\"VirtualName\":\"ephemeral1\"},{\"DeviceName\": \"/dev/sde\",\"VirtualName\":\"ephemeral2\"},{\"DeviceName\": \"/dev/sdf\",\"VirtualName\":\"ephemeral3\"}"
+EPHEMERAL_BLOCK_DEVICE_MAPPINGS=",{\"DeviceName\": \"/dev/sdc\",\"VirtualName\":\"ephemeral0\"},{\"DeviceName\": \"/dev/sdd\",\"VirtualName\":\"ephemeral1\"},{\"DeviceName\": \"/dev/sde\",\"VirtualName\":\"ephemeral2\"},{\"DeviceName\": \"/dev/sdf\",\"VirtualName\":\"ephemeral3\"}"
+
+# Experimental: If the user sets KUBE_AWS_STORAGE to ebs, use ebs storage
+# in preference to local instance storage We do this by not mounting any
+# instance storage.  We could do this better in future (e.g. making instance
+# storage available for other purposes)
+if [[ "${KUBE_AWS_STORAGE:-}" == "ebs" ]]; then
+  EPHEMERAL_BLOCK_DEVICE_MAPPINGS=""
+fi
 
 # TODO (bburns) Parameterize this for multiple cluster per project
-
 function get_vpc_id {
   $AWS_CMD describe-vpcs \
            --filters Name=tag:Name,Values=kubernetes-vpc \
@@ -417,8 +424,8 @@ function detect-root-device {
       ROOT_DEVICE_NODE=$($AWS_CMD describe-images --image-ids ${node_image} --query 'Images[].RootDeviceName')
   fi
 
-  MASTER_BLOCK_DEVICE_MAPPINGS="[{\"DeviceName\":\"${ROOT_DEVICE_MASTER}\",\"Ebs\":{\"DeleteOnTermination\":true,\"VolumeSize\":${MASTER_ROOT_DISK_SIZE},\"VolumeType\":\"${MASTER_ROOT_DISK_TYPE}\"}}, ${BLOCK_DEVICE_MAPPINGS_BASE}]"
-  NODE_BLOCK_DEVICE_MAPPINGS="[{\"DeviceName\":\"${ROOT_DEVICE_NODE}\",\"Ebs\":{\"DeleteOnTermination\":true,\"VolumeSize\":${NODE_ROOT_DISK_SIZE},\"VolumeType\":\"${NODE_ROOT_DISK_TYPE}\"}}, ${BLOCK_DEVICE_MAPPINGS_BASE}]"
+  MASTER_BLOCK_DEVICE_MAPPINGS="[{\"DeviceName\":\"${ROOT_DEVICE_MASTER}\",\"Ebs\":{\"DeleteOnTermination\":true,\"VolumeSize\":${MASTER_ROOT_DISK_SIZE},\"VolumeType\":\"${MASTER_ROOT_DISK_TYPE}\"}} ${EPHEMERAL_BLOCK_DEVICE_MAPPINGS}]"
+  NODE_BLOCK_DEVICE_MAPPINGS="[{\"DeviceName\":\"${ROOT_DEVICE_NODE}\",\"Ebs\":{\"DeleteOnTermination\":true,\"VolumeSize\":${NODE_ROOT_DISK_SIZE},\"VolumeType\":\"${NODE_ROOT_DISK_TYPE}\"}} ${EPHEMERAL_BLOCK_DEVICE_MAPPINGS}]"
 }
 
 # Computes the AWS fingerprint for a public key file ($1)