feat(ec2): can define Launch Templates (not use them yet)

packages/@aws-cdk/aws-ec2/README.md

@@ -999,3 +999,24 @@ const subnet = Subnet.fromSubnetAttributes(this, 'SubnetFromAttributes', {
 // Supply only subnet id
 const subnet = Subnet.fromSubnetId(this, 'SubnetFromId', 's-1234');
 ```
+
+## Launch Templates
+
+A Launch Template is a standardized template that contains the configuration information to launch an instance.
+They can be used when launching instances on their own, through Amazon EC2 Auto Scaling, EC2 Fleet, and Spot Fleet.
+Launch templates enable you to store launch parameters so that you do not have to specify them every time you launch
+an instance. For information on Launch Templates please see the
+[official documentation](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-launch-templates.html).
+
+The following demonstrates how to create a launch template with an Amazon Machine Image, and security group.
+
+```ts
+const vpc = new ec2.Vpc(...);
+// ...
+const template = new ec2.LaunchTemplate(this, 'LaunchTemplate', {
+  machineImage: new ec2.AmazonMachineImage(),
+  securityGroup: new ec2.SecurityGroup(this, 'LaunchTemplateSG', {
+    vpc: vpc,
+  }),
+});
+```

packages/@aws-cdk/aws-ec2/lib/index.ts

@@ -4,6 +4,7 @@ export * from './cfn-init';
 export * from './cfn-init-elements';
 export * from './instance-types';
 export * from './instance';
+export * from './launch-template';
 export * from './machine-image';
 export * from './nat';
 export * from './network-acl';

packages/@aws-cdk/aws-ec2/lib/instance.ts

@@ -8,9 +8,10 @@ import { Connections, IConnectable } from './connections';
 import { CfnInstance } from './ec2.generated';
 import { InstanceType } from './instance-types';
 import { IMachineImage, OperatingSystemType } from './machine-image';
+import { instanceBlockDeviceMappings } from './private/ebs-util';
 import { ISecurityGroup, SecurityGroup } from './security-group';
 import { UserData } from './user-data';
-import { BlockDevice, synthesizeBlockDeviceMappings } from './volume';
+import { BlockDevice } from './volume';
 import { IVpc, Subnet, SubnetSelection } from './vpc';
 
 /**
@@ -362,7 +363,7 @@ export class Instance extends Resource implements IInstance {
       subnetId: subnet.subnetId,
       availabilityZone: subnet.availabilityZone,
       sourceDestCheck: props.sourceDestCheck,
-      blockDeviceMappings: props.blockDevices !== undefined ? synthesizeBlockDeviceMappings(this, props.blockDevices) : undefined,
+      blockDeviceMappings: props.blockDevices !== undefined ? instanceBlockDeviceMappings(this, props.blockDevices) : undefined,
       privateIpAddress: props.privateIpAddress,
     });
     this.instance.node.addDependency(this.role);