set interfaces openvpn vtun10 description 'Server foo'
set interfaces openvpn vtun10 encryption cipher 'aes256'
set interfaces openvpn vtun10 hash 'sha512'
set interfaces openvpn vtun10 local-host '203.0.113.1'
set interfaces openvpn vtun10 local-port '1194'
set interfaces openvpn vtun10 mode 'server'
set interfaces openvpn vtun10 persistent-tunnel
set interfaces openvpn vtun10 protocol 'udp'
set interfaces openvpn vtun10 server client client1 ip '10.10.0.10'
set interfaces openvpn vtun10 server domain-name 'vyos.net'
set interfaces openvpn vtun10 server max-connections '250'
set interfaces openvpn vtun10 server mfa totp
set interfaces openvpn vtun10 server name-server '172.16.254.30'
set interfaces openvpn vtun10 server subnet '10.10.0.0/24'
set interfaces openvpn vtun10 server topology 'subnet'
set interfaces openvpn vtun10 tls ca-certificate 'ca'
set interfaces openvpn vtun10 tls certificate 'cert'
set interfaces openvpn vtun10 tls dh-params 'dh'
set interfaces openvpn vtun10 tls tls-version-min '1.0'

Apr 07 14:52:54 r14 systemd[1]: Starting openvpn@vtun10.service - OpenVPN connection to vtun10...
Apr 07 14:52:54 r14 openvpn-vtun10[3351]: PLUGIN_INIT: could not load plugin shared object /openvpn-otp.so: /openvpn-otp.so: cannot open shared object file: No such file or directory: No such file or directory (errno=2)
Apr 07 14:52:54 r14 openvpn-vtun10[3351]: Exiting due to fatal error
Apr 07 14:52:54 r14 systemd[1]: openvpn@vtun10.service: Main process exited, code=exited, status=1/FAILURE
Apr 07 14:52:54 r14 systemd[1]: openvpn@vtun10.service: Failed with result 'exit-code'.
Apr 07 14:52:54 r14 systemd[1]: Failed to start openvpn@vtun10.service - OpenVPN connection to vtun10.

vyos@r14:~$ sudo cat /run/openvpn/vtun10.conf | grep plugin
plugin "/openvpn-otp.so" "otp_secrets=/config/auth/openvpn/vtun10-otp-secrets otp_slop=180 totp_t0=0 totp_step=30 totp_digits=6 password_is_cr=1"
vyos@r14:~$