There are dozens of open source SSO, some are popular too and are productions ready, like KeyCloak, Authelia, Authentic, and others that can be found here (1),

There are dozens of open source SSO, some are popular too and are productions ready, like KeyCloak, Authelia, Authentic, and others that can be found here (1), however, keep in mind SSO has cons too from my experience besides what you mentioned -privacy wise: - if the SSO server is down (or the docker container), all other services are un accessible by your users - Any breaches to the SSO is a breach to all other services. - You should have more work done on enforcing passwords/login policies, creating some sort of granular access, support MFA, etc. (1) https://medevel.com/10-os-sso/ https://medevel.com/10-os-sso/