Hi,
if you refer to the man pages you will see the supported formats:
# man ipa-cacert-manage
...
The supported formats for the certificate files are DER, PEM and
PKCS#7 format.
...
# man ipa-server-certinstall
...
Replace the current Directory server SSL certificate, Apache server SSL
certificate and/or Kerberos KDC certificate with the certificate in the
specified files. The files are accepted in PEM and DER certificate,
PKCS#7 certificate chain, PKCS#8 and raw private key and PKCS#12 for‐
mats.
...
HTH,
flo