I have a lot of different services which I self host for me and my family like:
PeerTube
Lemmy
Mastodon
Synology NAS
TTRSS
NextCloud
Matrix
HomeAssistant
etc.
Right now every family member needs to create a user on each of those services and have a different password on them, which is OK when you use a Password Manager, but most of my extended family members don't. And they often forget their password and stop using the service because they can't figure out how to reset the password with each and every service.
I would like to try to consolidate all of it with a Single Sign-On (SSO) solution but It's not obvious to me if there is one which is not overly over engineered for hundreds of thousands of users but small and lightweight, perhaps even easy to set up.
I tried OpenLDAP but Jesus that was very involved.
Keycloak is decent. It has its own built in user database, or it can connect to an “upstream” idp like AD, GitHub, google, fb, basically anything that speaks openid or SAML. Then, it can act as an idp to each service you run. It is a bit of a chore to configure, but compared to other SSO servers it’s pretty good (looking at you shibboleth)