The base OpenSSH rc.d script has a nice undocumented set of options that easily allow to disable the automatic creation of undesired, and possibly outdated, keys.
Those options are: sshd_rsa1_enable, sshd_rsa_enable, sshd_dsa_enable, sshd_ecdsa_enable, sshd_ed25519_enable
It's possible to port those options in openssh-portable too? I think they are useful to avoid useless files and to increase the clarity of the overall configuration of a system.
For information, a simple workaround I found is to pre-create the empty files for the keys I don't want to be created. This works thanks to bug #202792.
As a final remark, the abovementioned options are quite undocumented in the system (not in the man pages). Could be nice to document them.
Thank for your support.
I don't have time to do it soon, but I'll gladly take a patch. Otherwise I can add this in a few weeks.
Is still not in:
but it is the question if this is stil wanted?.
(In reply to w.schwarzenfeld from comment #2)
Regarding the two original requests:
1) support of the options in openssh-portable: yes, I think is still wanted as those options exist for the base OpenSSH build.
2) documentation of the options in man pages and handbook (for base OpenSSH): still undocumented. I think they should be documented somewhere.