There used to be a time in history when a system administrator had to know all this shit in order to keep their job. I guess nowadays devops just means dev as we furiously pump tokens into the AI Wurlitzer whenever we dont know how to do something and hope it doesnt gaslight us into deleting prod.

- Freeipa is Linux AD, includes DNS, dogtag, and OpenLDAP.

- SSSD is how linux machines authenticate with a central directory. this includes AD.

- nss is the order of operations in which the system attempts lookups against various directories for services.

- pam is the subsystem of authentication in linux.

- kerberos is a ticket based authentication system started by MIT and popularized by Microsoft.

- ldap is a directory for information and authentication data

- DNS should not need an explanation.

Active Directory is the exact same byzantine architecture, the only reason you dont complain about it is because Microsoft has hidden nearly every meaningful internal from you with fun buttons and dropdowns like a childs toy.

Make no mistake, when it breaks it is much more cataclysmic in its complexity. major multinational corporations can spend weeks with external consultants and even Microsoft themselves trying to debug it. Most failure modes result in rebuilding the entire directory from scratch out of the sheer futility of trying to recover anything. things as simple as an OS update can cause the complete failure of the directory, replication, kerberos key subsystem, or even the ADUC tool you use to interface with any of this. Most of the time your only solution is to wait for MS to release a fix.

FreeIPA isnt complete. it doesnt include things like group policies or account expiration but its infinitely easier to debug. its individual components are well documented and offer standalone debug and trace features. most if its components have existed longer than their competitive Microsoft offerings, or at very least vastly outscale and outperform them.

Kubernetes is just as complex, but cloud providers will happily bill you by the nanosecond for the gentle equivalent of Microsofts buttons and dropdowns. Microsoft will gladly bill you for "cloud" based AD. You can just as easily deploy local users in ansible.

Native FreeBSD Kerberos/LDAP with FreeIPA/IDM