can't find fstab entry ?

[Bob Jones]

OpenBSD 6.0 GENERIC.MP#0 amd64

My fstab entry looks like :

10.10.10.10:/srv/share /mnt/ops_test nfs defaults,noexec,nosuid,nodev,auto 0 0

However:

$ doas mount /mnt/ops_test
doas (m...@example.com) password:
mount: can't find fstab entry for /mnt/ops_test


Any ideas  ?  That style of fstab entry seems to work fine on my linux
boxes (albeit with nfs4 instead of nfs, but that makes no difference
on openbsd).

Thanks !