-- | The stack's operating system, which must be set to one of the following.
--
-- Standard Linux operating systems: an Amazon Linux version such as 'AmazonLinux 2014.09', 'Ubuntu 12.04 LTS', or 'Ubuntu 14.04 LTS'. Custom Linux AMIs: 'Custom'. You specify the custom AMI you want to use when you create instances. Microsoft Windows Server 2012 R2.
-- The default option is the current Amazon Linux version.
usDefaultOs :: Lens' UpdateStack (Maybe Text)
usDefaultOs = lens _usDefaultOs (\s a -> s { _usDefaultOs = a })
usDefaultOs :: Lens' UpdateStack (Maybe Text)
usDefaultOs = lens _usDefaultOs (\s a -> s { _usDefaultOs = a })
usDefaultOs = lens _usDefaultOs (\s a -> s { _usDefaultOs = a })