D8: Update manager for multi-sites

I'm hoping that updates on a D8 multi-site, will be easier. One of the biggest hassles on D6 multi-sites, is the requirement to:

1. Log-in to each site, and put each into maintenance mode
2. Copy the updates core or modules
3. Run update.php for each multi-site
4. Take each site out of maintenance mode

On D8, I'd like to be able to perform a one-click update, and know that it has successfully propagated throughout my multi-sites.