ec2-user not used on Amazon Linux AMI

[sfzylad]

/kind bug

What steps did you take and what happened:
Once our Amazon Linux 2 AMI is used, the default user to be used with Amazon Linux is centos. The default user supported by AWS is ec2-user and is present in the system we provide. It's that cloud-init is comnfigured to use centos user:

# cat /etc/cloud/cloud.cfg
[...]
# System and/or distro specific settings
# (not accessible to handlers/transforms)
system_info:
   # This will affect which distro class gets used
   distro: centos
   # Default user name + that default users groups (if added/used)
   default_user:
     name: centos # <--- here's where the problem is
     lock_passwd: True
     gecos: centos Cloud User # <--- this should be changed too
     groups: [wheel, adm, systemd-journal]
     sudo: ["ALL=(ALL) NOPASSWD:ALL"]
     shell: /bin/bash
   # Other config here will be given to the distro class and/or path classes
   paths:
      cloud_dir: /var/lib/cloud/
      templates_dir: /etc/cloud/templates/
   ssh_svcname: sshd

What did you expect to happen:
When instance uses Amazon Linux, ec2-user system user should be used to loggin the instance.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• Cluster-api-provider-aws version:
• Kubernetes version: (use kubectl version):
• OS (e.g. from /etc/os-release):

[detiber]

/assign
/priority important-soon
/milestone v1alpha1

[detiber]

/lifecycle active

[detiber]

/remove-lifecycle active

It looks like the cloud-init config is populated at compile time, this will either require a separate build of cloud-init for Amazon Linux 2 or it will require some additional modifications in ansible post install to modify the config.

[sfzylad]

/lifecycle active