Openstack HOT, automatically setup static IP address to instance

It is possible to set up static IP using Openstack HOT (Heat Orchestration template), but it need to have 2 network attached. First interface to retrieve setting from cloud init injection and second interface is the one that will be use as main interface. First interface is local network that connected to internet. After instance is created, detach first interface with local network and then reboot the instance. After that, we can ssh to the server using the static IP address. Basically, this HOT, create instance with 2 interface and then change the interface configuration using script defined in the runcmd section.

Below is the HOT content.

heat_template_version: 2016-04-08
parameters:
  key_name:
    type: string
    default: default
  server_name:
    type: string
    default: server-name
    description: instance name
  flavor:
    type: string
    default: flavor1
    constraints:
      - allowed_values: [flavor1, flavor2]
  image:
    type: string
    default: centos
    constraints:
      - allowed_values: [centos, debian, ubuntu, opensuse, fedora]
  provider_net_id:
    type: string
    default: 123af45-ac98-411c-d698-ec88b37dd093
    label: external network id
  private_net_name:
    type: string
    description: private-network
    default: private-net
  root_pw2:
    type: string
    description: root password
    default: root_password
  user_pw:
    type: string
    description: user password
    default: user_password
  gw_ip:
    type: string
    description: ip gateway
  netmask:
    type: string
    description: netmask of the network
  dns:
    type: string
    description: dns server
    default: 1.1.1.1

resources:
   instance1_port1:
      type: OS::Neutron::Port
      properties:
         admin_state_up: true
         network_id: { get_param: provider_net_id }
         security_groups:
            - default

   instance1:
      type: OS::Nova::Server
      properties:
         name: { get_param: server_name }
         image: { get_param: image }
         flavor:  { get_param: flavor }
         availability_zone: zone1
         networks:
            - network: {get_param: private_net_name}
            - port: { get_resource: instance1_port1 }
         user_data_format: RAW
         user_data:
           str_replace:
             template: |
               #cloud-config
               final_message: "The system is finally up, after $UPTIME seconds"
               ssh_pwauth: True
               disable_root: false
               users:
                 - name: user
                   groups: users
                   shell: /bin/bash
                   sudo: ALL=(ALL) NOPASSWD:ALL
                   lock_passwd: false
               chpasswd:
                 list: |
                   user:$CLOUDPW
                   root:$ROOTPW
                 expire: False
               runcmd:
                 - "if egrep 'rhel|centos|fedora|suse' /etc/os-release; then ifdown eth0; if egrep 'suse' /etc/os-release; then ifdir='/etc/sysconfig/network'; else ifdir='/etc/sysconfig/network-scripts'; fi; rm -f $ifdir/ifcfg-eth0; echo 'Delete ifcfg-eth0'; elif egrep 'debian|ubuntu' /etc/os-release; then rm -f /etc/network/interfaces.d/50-cloud-init.cfg; echo 'network: {config: disabled}' > /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg; else echo 'OS NOT DETECTED';exit 1;fi;"
                 - "if egrep 'rhel|centos|fedora' /etc/os-release; then ifdir='/etc/sysconfig/network-scripts'; macadd=$(ip -o link | grep eth1 | cut -d/ -f2 | awk {'print $2'});if [ ! -e ${ifdir}'/ifcfg-eth0' ];then echo 'Creating iface file for ifcfg-eth0';echo -e 'TYPE=Ethernet\nIPADDR='$PROVIP'\nHWADDR='$macadd'\nPREFIX=26\nDEFROUTE=yes\nDEVICE=eth0\nONBOOT=yes\nGATEWAY='$GWIP'\nDNS1='$DNS > $ifdir'/ifcfg-eth0'; ifup eth0; fi; elif egrep 'debian|ubuntu' /etc/os-release; then if egrep 'ID=ubuntu' /etc/os-release; then theline=2; else theline=2; fi; ifname0=$(ip -o link | awk 'NR=='$theline | cut -d: -f2 | awk {'print $1'}); ifdown $ifname0; ifdir='/etc/network/interfaces';if [ -e $ifdir ];then echo 'Add '$ifname0' to '$ifdir;echo 'auto lo\niface lo inet loopback\n\nauto '$ifname0'\niface '$ifname0' inet static\naddress '$PROVIP'\nnetmask '$NETMASK'\ngateway '$GWIP'\ndns-nameservers '$DNS > $ifdir; ifup $ifname0; fi; elif egrep 'suse' /etc/os-release; then if egrep 'sles' /etc/os-release; then theline=2; else theline=3; fi; ifdir='/etc/sysconfig/network'; ifname0=$(ip -o link | awk 'NR=='$theline | cut -d: -f2 | awk {'print $1'}); ifdown $ifname0; echo 'Add '$ifname0' to '$ifdir; echo 'STARTMODE=auto\nBOOTPROTO=static\nIPADDR='$PROVIP'/26\nUSERCONTROL=no\nNM_CONTROLLED=no\nBRIDGE=no' > $ifdir'/ifcfg-'$ifname0; echo 'default '$GWIP' - -' > /etc/sysconfig/network/routes; echo 'nameserver '$DNS >> /etc/resolv.conf; ifup $ifname0; else echo 'OS NOT DETECTED'; exit 1; fi;"
                 - "sed -i '/PasswordAuthentication no/d' /etc/ssh/sshd_config"
             params:
               $PROVIP: { get_attr: [ instance1_port1, fixed_ips, 0, ip_address ] }
               $ROOTPW: { get_param: root_pw2 }
               $CLOUDPW: { get_param: cloud_pw }                
               $GWIP: { get_param: gw_ip }                
               $NETMASK: { get_param: netmask }                
               $DNS: { get_param: dns }
outputs:
   instance1_static_ip:
      description: Fixed IP address of port.
      value: { get_attr: [ instance1_port1, fixed_ips, 0, ip_address ] }