cloud-init-centos-7.6-ipv4-ena.yml

#cloud-config
# vim: syntax=yaml
# cloud-init-centos-7-ipv4-ena.yml
#
# This one is intended for new instances where:
# * the ENA adapter is in use, for example for the t3 and m5 instance types.
# * you want IPv4 networking only
#
# This has both ens3 and ens5 in it, although only one of these usually appears in practice,
# due to variability people have reported in starting up ena instances when the grub command
# line parameter "net.ifnames=0" is not present.
#
# Partially derived from:
# * pakdel's sketch of a network service remediation script in https://bugs.centos.org/view.php?id=13836
# * ldennison's comment in https://bugs.centos.org/view.php?id=14760 
# * hhsnow's comment in https://bugs.centos.org/view.php?id=14107
# * the cloud-init config in https://docs.aws.amazon.com/vpc/latest/userguide/vpc-migrate-ipv6.html#vpc-migrate-ipv6-instance-types
#
# Tested on CentOS Linux release 7.6.1810 (Core) and a t3.micro
# instance on 2019-05-19
#
# Author:
#    Richard Bullington-Mcguire <rbulling@obscure.org> / @obscurerichard 
#
# Copyright (C) 2019 by The Obscure Organization
# MIT licensed. See the LICENSE file for details.
network:
  version: 1
  config:
  - type: physical
    name: ens3
    subnets:
      - type: dhcp4
  - type: physical
    name: ens5
    subnets:
      - type: dhcp4
bootcmd:
  - |
    rm -f /etc/sysconfig/network-scripts/ifcfg-eth0
    for PATH_DHCLIENT_PID in /var/run/dhclient*; do
        export PATH_DHCLIENT_PID
        dhclient -r
        # Making sure it really truly stopped
        kill $(<PATH_DHCLIENT_PID) || true
        rm -f "$PATH_DHCLIENT_PID"
    done
    systemctl restart network