Reduce number of unnecessary elastic IPs

Author: nhatnghiho

tests/ci/cdk/cdk/aws_lc_ec2_test_framework_ci_stack.py

@@ -94,7 +94,12 @@ def __init__(
         )
 
         # create vpc for ec2s
-        vpc = ec2.Vpc(self, id="{}-ec2-vpc".format(id))
+        vpc = ec2.Vpc(
+            self,
+            id="{}-ec2-vpc".format(id),
+            nat_gateways=1 # minimize the number of idle NAT gateways and thus elastic IPs
+        )
+
         selected_subnets = vpc.select_subnets(
             subnet_type=ec2.SubnetType.PRIVATE_WITH_EGRESS
         )

tests/ci/cdk/cdk/linux_docker_image_batch_build_stack.py

@@ -89,7 +89,11 @@ def __init__(
         }
 
         # Define VPC
-        vpc = ec2.Vpc(self, id="{}-ec2-vpc".format(id))
+        vpc = ec2.Vpc(
+            self,
+            id="{}-ec2-vpc".format(id),
+            nat_gateways=1 # minimize the number of idle NAT gateways and thus elastic IPs
+        )
 
         # Define CodeBuild project.
         project = codebuild.Project(

tests/ci/cdk/cdk/windows_docker_image_build_stack.py

@@ -102,7 +102,11 @@ def __init__(
         machine_image = ec2.MachineImage.latest_windows(
             ec2.WindowsVersion.WINDOWS_SERVER_2019_ENGLISH_FULL_BASE
         )
-        vpc = ec2.Vpc(scope=self, id="{}-vpc".format(id))
+        vpc = ec2.Vpc(
+            scope=self,
+            id="{}-vpc".format(id),
+            nat_gateways=1 # minimize the number of idle NAT gateways and thus elastic IPs
+        )
         block_device_volume = ec2.BlockDeviceVolume.ebs(
             volume_size=200, delete_on_termination=True
         )