From 5f10c284c8cdee9be507d61e87257866cba18b87 Mon Sep 17 00:00:00 2001
From: Maciej Borsz <maciejborsz@google.com>
Date: Wed, 5 Jun 2019 13:09:18 +0200
Subject: [PATCH] Modify kube-up to support cluster without nodes.

---
 cluster/gce/config-default.sh | 4 ++++
 cluster/gce/config-test.sh    | 4 ++++
 cluster/gce/util.sh           | 8 +++++---
 cluster/validate-cluster.sh   | 6 +++++-
 4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/cluster/gce/config-default.sh b/cluster/gce/config-default.sh
index d38723996e2..6446bfe9daa 100755
--- a/cluster/gce/config-default.sh
+++ b/cluster/gce/config-default.sh
@@ -41,6 +41,10 @@ NODE_LOCAL_SSDS=${NODE_LOCAL_SSDS:-0}
 NODE_LABELS="${KUBE_NODE_LABELS:-}"
 WINDOWS_NODE_LABELS="${WINDOWS_NODE_LABELS:-}"
 
+# KUBE_CREATE_NODES can be used to avoid creating nodes, while master will be sized for NUM_NODES nodes.
+# Firewalls and node templates are still created.
+KUBE_CREATE_NODES="${KUBE_CREATE_NODES:-true}"
+
 # An extension to local SSDs allowing users to specify block/fs and SCSI/NVMe devices
 # Format of this variable will be "#,scsi/nvme,block/fs" you can specify multiple
 # configurations by separating them by a semi-colon ex. "2,scsi,fs;1,nvme,block"
diff --git a/cluster/gce/config-test.sh b/cluster/gce/config-test.sh
index b2ce6d5703a..739c9e31508 100755
--- a/cluster/gce/config-test.sh
+++ b/cluster/gce/config-test.sh
@@ -41,6 +41,10 @@ NODE_LOCAL_SSDS=${NODE_LOCAL_SSDS:-0}
 NODE_LABELS="${KUBE_NODE_LABELS:-}"
 WINDOWS_NODE_LABELS="${WINDOWS_NODE_LABELS:-}"
 
+# KUBE_CREATE_NODES can be used to avoid creating nodes, while master will be sized for NUM_NODES nodes.
+# Firewalls and node templates are still created.
+KUBE_CREATE_NODES="${KUBE_CREATE_NODES:-true}"
+
 # An extension to local SSDs allowing users to specify block/fs and SCSI/NVMe devices
 # Format of this variable will be "#,scsi/nvme,block/fs" you can specify multiple
 # configurations by separating them by a semi-colon ex. "2,scsi,fs;1,nvme,block"
diff --git a/cluster/gce/util.sh b/cluster/gce/util.sh
index 7983467f146..5f72c5d2d59 100755
--- a/cluster/gce/util.sh
+++ b/cluster/gce/util.sh
@@ -2134,9 +2134,11 @@ function kube-up() {
     create-master
     create-nodes-firewall
     create-nodes-template
-    # Windows nodes take longer to boot and setup so create them first.
-    create-windows-nodes
-    create-linux-nodes
+    if [[ "${KUBE_CREATE_NODES}" == "true" ]]; then
+      # Windows nodes take longer to boot and setup so create them first.
+      create-windows-nodes
+      create-linux-nodes
+    fi
     check-cluster
   fi
 }
diff --git a/cluster/validate-cluster.sh b/cluster/validate-cluster.sh
index a2848149e73..9b851135b1f 100755
--- a/cluster/validate-cluster.sh
+++ b/cluster/validate-cluster.sh
@@ -51,7 +51,11 @@ ALLOWED_NOTREADY_NODES="${ALLOWED_NOTREADY_NODES:-0}"
 CLUSTER_READY_ADDITIONAL_TIME_SECONDS="${CLUSTER_READY_ADDITIONAL_TIME_SECONDS:-30}"
 
 if [[ "${KUBERNETES_PROVIDER:-}" == "gce" ]]; then
-  EXPECTED_NUM_NODES="$(get-num-nodes)"
+  if [[ "${KUBE_CREATE_NODES}" == "true" ]]; then
+    EXPECTED_NUM_NODES="$(get-num-nodes)"
+  else
+    EXPECTED_NUM_NODES="0"
+  fi
   echo "Validating gce cluster, MULTIZONE=${MULTIZONE:-}"
   # In multizone mode we need to add instances for all nodes in the region.
   if [[ "${MULTIZONE:-}" == "true" ]]; then