If you wanted to configure the DNS through the cloud config file, you’ll need to place DNS configurations within the rancher key.

#cloud-config

#Remember, any changes for rancher will be within the rancher key
rancher:
  network:
    dns:
      search:
        - mydomain.com
        - example.com

Using ros config, you can set the nameservers, and search, which directly map to the fields of the same name in /etc/resolv.conf.

$ sudo ros config set rancher.network.dns.search "['mydomain.com','example.com']"
$ sudo ros config get rancher.network.dns.search
- mydomain.com
- example.com