Tested and working following the basic (but at least some) test from:
https://git.launchpad.net/qa-regression-testing/tree/notes_testing/openvpn/README.vm

Ends up with:

root@eoan-openvpn-cl:/etc/openvpn# service openvpn@client start
root@eoan-openvpn-cl:/etc/openvpn# 
Broadcast message from root@eoan-openvpn-cl (Mon 2019-05-13 14:56:43 UTC):

Password entry required for 'Enter Private Key Password:' (PID 9320).
Please enter password with the systemd-tty-ask-password-agent tool:


root@eoan-openvpn-cl:/etc/openvpn# systemd-tty-ask-password-agent
Enter Private Key Password: ******
root@eoan-openvpn-cl:/etc/openvpn# service openvpn@client status
● <email address hidden> - OpenVPN connection to client
   Loaded: loaded (/lib/systemd/system/openvpn@.service; disabled; vendor preset: enabled)
   Active: active (running) since Mon 2019-05-13 14:56:43 UTC; 9s ago
     Docs: man:openvpn(8)
           https://community.openvpn.net/openvpn/wiki/Openvpn24ManPage
           https://community.openvpn.net/openvpn/wiki/HOWTO
 Main PID: 9309 (openvpn)
   Status: "Initialization Sequence Completed"
    Tasks: 1 (limit: 541)
   Memory: 1.9M
   CGroup: /<email address hidden>
           └─9309 /usr/sbin/openvpn --daemon ovpn-client --status /run/openvpn/client.status 10 --cd /etc/openvpn --script-security 2 --config /etc/openvpn/client.conf --writepid /run/openvp

May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: Data Channel: using negotiated cipher 'AES-256-GCM'
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: Outgoing Data Channel: Cipher 'AES-256-GCM' initialized with 256 bit key
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: Incoming Data Channel: Cipher 'AES-256-GCM' initialized with 256 bit key
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: ROUTE_GATEWAY 192.168.122.1/255.255.255.0 IFACE=ens3 HWADDR=52:54:00:ab:e9:6c
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: TUN/TAP device tun0 opened
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: TUN/TAP TX queue length set to 100
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: /sbin/ip link set dev tun0 up mtu 1500
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: /sbin/ip addr add dev tun0 local 10.8.0.6 peer 10.8.0.5
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: /sbin/ip route add 10.8.0.1/32 via 10.8.0.5
May 13 14:56:50 eoan-openvpn-cl ovpn-client[9309]: Initialization Sequence Completed
root@eoan-openvpn-cl:/etc/openvpn# ifconfig tun0
tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 10.8.0.6  netmask 255.255.255.255  destination 10.8.0.5
        inet6 fe80::41b:f9cf:8b6a:521d  prefixlen 64  scopeid 0x20<link>
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 100  (UNSPEC)
        RX packets 1  bytes 48 (48.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2  bytes 96 (96.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

root@eoan-openvpn-cl:/etc/openvpn# ping 10.8.0.1
PING 10.8.0.1 (10.8.0.1) 56(84) bytes of data.
64 bytes from 10.8.0.1: icmp_seq=1 ttl=64 time=0.392 ms
64 bytes from 10.8.0.1: icmp_seq=2 ttl=64 time=0.494 ms
^C
--- 10.8.0.1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 7ms
rtt min/avg/max/mdev = 0.392/0.443/0.494/0.051 ms
root@eoan-openvpn-cl:/etc/openvpn# netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         192.168.122.1   0.0.0.0         UG        0 0          0 ens3
10.8.0.1        10.8.0.5        255.255.255.255 UGH       0 0          0 tun0
10.8.0.5        0.0.0.0         255.255.255.255 UH        0 0          0 tun0
192.168.122.0   0.0.0.0         255.255.255.0   U         0 0          0 ens3
192.168.122.1   0.0.0.0         255.255.255.255 UH        0 0          0 ens3