Usage

node "server.domain.com" inherits basenode {
    # physical interface
    network::interface { "eth0":
        hostname => "server.domain.com",
        ipaddress => "1.2.3.4",
        gateway => "1.2.3.1",
        netmask => "255.255.255.0",
        network => "1.2.3.0",
        broadcast => "1.2.3.255",
        macaddress => "ff:ff:ff:ff:ff:ff",
        ensure => up
    }

    # aliased interface
    network::alias { "eth0:1":
        ipaddress => "1.2.3.5",
        netmask => "255.255.255.0",
        network => "1.2.3.0",
        broadcast => "1.2.3.255",
        ensure => up
    }
}

Miscellaneous Notes

Probably only works with RH-ish systems.