The current CNAMEs (e.g. enwiki.analyatics.db.svc.wmflabs) are created by iterating the s[1-7].dblist files as read from noc.wikimedia.org. This will get all of the wikidb names, but it misses creating aliases for non-wiki databases like centralauth.
$ sql -vv --cluster=analytics centralauth Looking up centralauth.analytics.db.svc.eqiad.wmflabs Could not find requested database Make sure to ask for a db in format of <wiki>_p $ sql -vv --cluster=labsdb centralauth Looking up centralauth.labsdb Resolved centralauth_p to centralauth.labsdb Connecting to centralauth.labsdb ['mysql', '--defaults-file=/home/bd808/replica.my.cnf', '-h', 'centralauth.labsdb', 'centralauth_p'] Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 51452892 Server version: 10.0.22-MariaDB MariaDB Server Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. (u3518@centralauth.labsdb) [centralauth_p]>