ssh-key-dir is an sshd AuthorizedKeysCommand that reads SSH authorized key files from a directory, ~/.ssh/authorized_keys.d. It allows SSH keys to be managed by multiple tools and processes, without competing over ~/.ssh/authorized_keys.

ssh-key-dir reads key files in lexigraphical order, ignoring any filenames starting with a dot.

ssh-key-dir is packaged in Fedora:

sudo dnf install ssh-key-dir

Installing the package automatically configures sshd to read keys using ssh-key-dir.

You can also install just the ssh-key-dir binary with Rust's Cargo package manager:

cargo install ssh-key-dir

To build from the source tree:

make

To install the binary and sshd_config.d fragment to a target rootfs (e.g. under a coreos-assembler workdir):

make install DESTDIR=/my/dest/dir