Business case:

sssd implemented its own internal DNS resolver due to some limitations. That has a complex history.  Changing it out would be a serious burden. Since there is no api in glibc to return structured information from /etc/gai.conf, this leaves the two somewhat out of sync since glibc defaults to IPv6 first and sssd defaults to IPv4 first.

Technical requirements:

Some way to have sssd use the content of /etc/gai.conf to define its lookup ordering.  

Timeline:

RHEL 10.4?

Upstream bug:

The closest I've got is https://github.com/SSSD/sssd/issues/5765#issuecomment-1750704627

can assist with testing.

Additional info:

https://man7.org/linux/man-pages/man3/getaddrinfo_a.3.html
man sssd.conf -> lookup_family_order

My perfect world would pass all this directly down to the glibc builtins.  But I think musl libc doesn't have that api.  Adding a glibc specific hook set might be a deal breaker.  Extending the glibc API might come with similar complications.

Describe the impact to you or the business

This caused a production outage on our RHEL10 hosts as we thought sssd was honoring gai.conf.  Fixed with config management.