I have a multisite drupal instance each with their own database but I want users to be logged in on all of them once they log into any one of them.
I found another question asking for something similar but it is for drupal 7 and it seems like it assumes each site is using the same database (I think)
How to share user and user profile in a multisite environment?
I do see a 'sessions' table but I'm not sure how to make each site use the same one.