Allow to configure number of kube-masters (#5073)

Change-Id: Ia3f30a1216b3ea063cd72c839ef6dff753cf10c6

contrib/inventory_builder/inventory.py

@@ -59,6 +59,7 @@ def get_var_as_bool(name, default):
 
 
 CONFIG_FILE = os.environ.get("CONFIG_FILE", "./inventory/sample/hosts.yaml")
+KUBE_MASTERS = int(os.environ.get("KUBE_MASTERS_MASTERS", 2))
 # Reconfigures cluster distribution at scale
 SCALE_THRESHOLD = int(os.environ.get("SCALE_THRESHOLD", 50))
 MASSIVE_SCALE_THRESHOLD = int(os.environ.get("SCALE_THRESHOLD", 200))
@@ -96,9 +97,10 @@ class KubesprayInventory(object):
             etcd_hosts_count = 3 if len(self.hosts.keys()) >= 3 else 1
             self.set_etcd(list(self.hosts.keys())[:etcd_hosts_count])
             if len(self.hosts) >= SCALE_THRESHOLD:
-                self.set_kube_master(list(self.hosts.keys())[etcd_hosts_count:5])
+                self.set_kube_master(list(self.hosts.keys())[
+                    etcd_hosts_count:(etcd_hosts_count + KUBE_MASTERS)])
             else:
-                self.set_kube_master(list(self.hosts.keys())[:2])
+                self.set_kube_master(list(self.hosts.keys())[:KUBE_MASTERS])
             self.set_kube_node(self.hosts.keys())
             if len(self.hosts) >= SCALE_THRESHOLD:
                 self.set_calico_rr(list(self.hosts.keys())[:etcd_hosts_count])
@@ -203,11 +205,11 @@ class KubesprayInventory(object):
             try:
                 # Python 3.x
                 start = int(ip_address(start_address))
-                end   = int(ip_address(end_address))
+                end = int(ip_address(end_address))
             except:
                 # Python 2.7
                 start = int(ip_address(unicode(start_address)))
-                end   = int(ip_address(unicode(end_address)))
+                end = int(ip_address(unicode(end_address)))
             return [ip_address(ip).exploded for ip in range(start, end + 1)]
 
         for host in hosts: