Refactor the "gcloud compute instances create" call as well.

cluster/gce/upgrade.sh

@@ -79,23 +79,7 @@ function upgrade-master() {
     --zone "${ZONE}" \
     "${MASTER_NAME}"
 
-  write-master-env
-  gcloud compute instances create "${MASTER_NAME}" \
-    --address "${MASTER_NAME}-ip" \
-    --project "${PROJECT}" \
-    --zone "${ZONE}" \
-    --machine-type "${MASTER_SIZE}" \
-    --image-project="${IMAGE_PROJECT}" \
-    --image "${IMAGE}" \
-    --tags "${MASTER_TAG}" \
-    --network "${NETWORK}" \
-    --scopes "storage-ro" "compute-rw" \
-    --can-ip-forward \
-    --metadata-from-file \
-      "startup-script=${KUBE_ROOT}/cluster/gce/configure-vm.sh" \
-      "kube-env=${KUBE_TEMP}/master-kube-env.yaml" \
-    --disk name="${MASTER_NAME}-pd" device-name=master-pd mode=rw boot=no auto-delete=no
-
+  create-master-instance "${MASTER_NAME}-ip"
   wait-for-master
 }
 

cluster/gce/util.sh

@@ -487,6 +487,42 @@ function write-node-env {
   build-kube-env false "${KUBE_TEMP}/node-kube-env.yaml"
 }
 
+# create-master-instance creates the master instance. If called with
+# an argument, the argument is used as the name to a reserved IP
+# address for the master. (In the case of upgrade/repair, we re-use
+# the same IP.)
+#
+# It requires a whole slew of assumed variables, partially due to to
+# the call to write-master-env. Listing them would be rather
+# futile. Instead, we list the required calls to ensure any additional
+# variables are set:
+#   ensure-temp-dir
+#   detect-project
+#   get-password
+#   set-master-htpasswd
+#
+function create-master-instance {
+  local address_opt=""
+  [[ -n ${1:-} ]] && address_opt="--address ${1}"
+
+  write-master-env
+  gcloud compute instances create "${MASTER_NAME}" \
+    ${address_opt} \
+    --project "${PROJECT}" \
+    --zone "${ZONE}" \
+    --machine-type "${MASTER_SIZE}" \
+    --image-project="${IMAGE_PROJECT}" \
+    --image "${IMAGE}" \
+    --tags "${MASTER_TAG}" \
+    --network "${NETWORK}" \
+    --scopes "storage-ro" "compute-rw" \
+    --can-ip-forward \
+    --metadata-from-file \
+      "startup-script=${KUBE_ROOT}/cluster/gce/configure-vm.sh" \
+      "kube-env=${KUBE_TEMP}/master-kube-env.yaml" \
+    --disk name="${MASTER_NAME}-pd" device-name=master-pd mode=rw boot=no auto-delete=no
+}
+
 # Instantiate a kubernetes cluster
 #
 # Assumed vars
@@ -546,21 +582,7 @@ function kube-up {
   # https://github.com/GoogleCloudPlatform/kubernetes/issues/3168
   KUBELET_TOKEN=$(dd if=/dev/urandom bs=128 count=1 2>/dev/null | base64 | tr -d "=+/" | dd bs=32 count=1 2>/dev/null)
 
-  write-master-env
-  gcloud compute instances create "${MASTER_NAME}" \
-    --project "${PROJECT}" \
-    --zone "${ZONE}" \
-    --machine-type "${MASTER_SIZE}" \
-    --image-project="${IMAGE_PROJECT}" \
-    --image "${IMAGE}" \
-    --tags "${MASTER_TAG}" \
-    --network "${NETWORK}" \
-    --scopes "storage-ro" "compute-rw" \
-    --can-ip-forward \
-    --metadata-from-file \
-      "startup-script=${KUBE_ROOT}/cluster/gce/configure-vm.sh" \
-      "kube-env=${KUBE_TEMP}/master-kube-env.yaml" \
-    --disk name="${MASTER_NAME}-pd" device-name=master-pd mode=rw boot=no auto-delete=no &
+  create-master-instance &
 
   # Create a single firewall rule for all minions.
   create-firewall-rule "${MINION_TAG}-all" "${CLUSTER_IP_RANGE}" "${MINION_TAG}" &