Update hostname and FQDN

For a full list of keys, refer to the update hostname module schema.

Default behavior

When preserve_hostname is not specified, cloud-init updates /etc/hostname per-boot based on the cloud-provided local-hostname setting. If you manually change /etc/hostname after boot, cloud-init will no longer modify it.

This default cloud-init behavior is equivalent to this cloud-config:

1#cloud-config
2preserve_hostname: false

Note that the same cloud-config will also prevent cloud-init from updating the system hostname.

Prevent updates to /etc/hostname

This example will prevent cloud-init from updating the system hostname or /etc/hostname.

1#cloud-config
2preserve_hostname: true

Set hostname

This example sets the hostname to external.fqdn.me instead of myhost.

1#cloud-config
2fqdn: external.fqdn.me
3hostname: myhost
4prefer_fqdn_over_hostname: true
5create_hostname_file: true

Override meta-data

Set the hostname to external instead of external.fqdn.me when meta-data provides the local-hostname: external.fqdn.me.

1#cloud-config
2prefer_fqdn_over_hostname: false

Don’t create /etc/hostname file

On a machine without an /etc/hostname file, this config instructs cloud-init not to create one.

In most clouds, this will result in a DHCP-configured hostname provided by the cloud.

1#cloud-config
2create_hostname_file: false