Simple heat stack(Tested on quickstart environment with OpenStack Ocata release)

test-stack.yml

heat_template_version: 2016-10-14

description: Simple template to deploy a single compute instance. Need to change image name

parameters:
  image:
    type: string
    description: Image name or id
    default: cirros

resources:
  psachin_instance-1:
    type: OS::Nova::Server
    properties:
      key_name: { get_resource: mykey }
      image: { get_param: image }
      flavor: { get_resource: flavor-cirros}
      networks:
        - port: { get_resource: instance_port }

  flavor-cirros:
    type: OS::Nova::Flavor
    properties:
      name: "cirros"
      ram: 100 
      vcpus: 1
      disk: 1
      
  mykey:
    type: OS::Nova::KeyPair
    properties:
      name: psachin
      save_private_key: true

  ping-ssh:
    type: OS::Neutron::SecurityGroup
    properties:
      rules:
        - protocol: tcp
          remote_ip_prefix: 0.0.0.0/0
          port_range_min: 22
          port_range_max: 22
        - protocol: icmp
          remote_ip_prefix: 0.0.0.0/0

  public-net:
    description: External network   
    type: OS::Neutron::ProviderNet
    properties:
      name: public-net
      network_type: flat
      physical_network: datacentre
      router_external: true

  public-net-subnet:
    type: OS::Neutron::Subnet
    properties:
      name: public-subnet
      network_id: { get_resource: public-net }
      cidr: 192.168.24.0/24
      allocation_pools: [{"start": "192.168.24.100", "end": "192.168.24.120"}]
      enable_dhcp: false
      gateway_ip: "192.168.24.1"
   
  int-green:
    description: internal network
    type: OS::Neutron::Net
    properties:
      name: int-green

  int-green-subnet:
    type: OS::Neutron::Subnet
    properties:
      network_id: { get_resource: int-green }
      cidr: 30.0.0.0/24
      dns_nameservers: ["8.8.8.8"]

  router-green:
    type: OS::Neutron::Router
    properties:
      external_gateway_info: { network: { get_resource: public-net }}
 
  router-green-interface:
    type: OS::Neutron::RouterInterface
    properties:
      router: { get_resource: router-green }
      subnet: { get_resource: int-green-subnet }

  instance_port:
    type: OS::Neutron::Port
    properties:
      network: { get_resource: int-green}
      security_groups: [ { get_resource: ping-ssh } ]
      fixed_ips:
        - subnet_id: { get_resource: int-green-subnet }

  floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network: { get_resource: public-net }
      port_id: { get_resource: instance_port }

triple-quickstart environment( commit 0a5dc8de8df3ddbf1886b8416b55464b0910c7ba)

Download image

curl http://download.cirros-cloud.net/0.3.5/cirros-0.3.5-x86_64-disk.img -o cirros-0.3.5-x86_64-disk.img

Create glance image

openstack image create --public --container-format bare --file cirros-0.3.5-x86_64-disk.img cirros

```
openstack  network create ext-net --external --provider-physical-network datacentre --provider-network-type flat
openstack subnet create ext-subnet --network ext-net --subnet-range 192.168.24.0/24  --allocation-pool start=192.168.24.100,end=192.168.24.120 --no-dhcp --gateway 192.168.24.1
```

Launch stack using
```
openstack stack create --template test-stack.yml test-stack
```

Output
```
[stack@undercloud ]$ openstack server list
+--------------------------------------+-----------------------------------------------+--------+------------------------------------+------------+
| ID                                   | Name                                          | Status | Networks                           | Image Name |
+--------------------------------------+-----------------------------------------------+--------+------------------------------------+------------+
| c14904d2-bc35-48a3-bc75-7b778eb02acd | test-stack-test_instance-1-adgli2qymnzm       | ACTIVE | int-green=30.0.0.8, 192.168.24.110 | cirros     |
+--------------------------------------+-----------------------------------------------+--------+------------------------------------+------------+
```