'Register system to RHN.  If enable_eus=True, extended update
support will be requested.'

def register(self, enable_eus=False, activationkey=None, profilename=None, sslcacert=None, systemorgid=None):

    register_cmd = ['/usr/sbin/rhnreg_ks', '--force']
    if self.username:
        register_cmd.extend(['--username', self.username, '--password', self.password])
    if self.server_url:
        register_cmd.extend(['--serverUrl', self.server_url])
    if enable_eus:
        register_cmd.append('--use-eus-channel')
    if (activationkey is not None):
        register_cmd.extend(['--activationkey', activationkey])
    if (profilename is not None):
        register_cmd.extend(['--profilename', profilename])
    if (sslcacert is not None):
        register_cmd.extend(['--sslCACert', sslcacert])
    if (systemorgid is not None):
        register_cmd.extend(['--systemorgid', systemorgid])
    (rc, stdout, stderr) = self.module.run_command(register_cmd, check_rc=True)
