I've successfully installed FreeIPA with container but have some issues with DNS.
root@turris:~# dig @<DNS IP address>
google.com
;; communications error to <DNS IP address>#53: connection refused
;; communications error to <DNS IP address>53: connection refused
;; communications error to <DNS IP address>#53: connection refused
; <<>> DiG 9.18.11 <<>> @<DNS IP address>
google.com
; (1 server found)
;; global options: +cmd
;; no servers could be reached