First of all, you will need to install Docker in case you don’t have already installed that

Here the quick way:

Docker easy way to copy&paste install on the Ubuntu 18+

Second, you will need to create ovpn-install.sh file and copy&paste code bellow

#!/bin/bash

myip=
while IFS=$': \\t' read -a line ;do
    [ -z "${line%inet}" ] && ip=${line[${#line[1]}>4?1:2]} &&
        [ "${ip#127.0.0.1}" ] && myip=$ip
  done< <(LANG=C /sbin/ifconfig)

apt update
apt install -y expect

mkdir -p openvpn/ovpns

cat > ./openvpn/addvpnuser.sh << EOF
#!/usr/bin/expect -f

# Run example expect ./addvpnuser.sh username
set CLIENTNAME [lindex \\$argv 0];
set timeout -1

spawn echo "\\$CLIENTNAME"

# with a passphrase (recommended)
# docker-compose run --rm openvpn easyrsa build-client-full $CLIENTNAME
# without a passphrase (not recommended)
spawn docker-compose run --rm openvpn easyrsa build-client-full \\$CLIENTNAME nopass
sleep 5
expect "Enter pass phrase for /etc/openvpn/pki/private/ca.key:"
sleep 3
send -- "Ir3hp3sFM30yFFob\\r";
expect eof

EOF

cat > ./openvpn/revokeuser.sh << EOF
#!/usr/bin/expect -f

# Run example expect ./revokeuser.sh username
set CLIENTNAME [lindex \\$argv 0];
set timeout -1

spawn echo "\\$CLIENTNAME"

spawn docker-compose run --rm openvpn ovpn_revokeclient \\$CLIENTNAME nopass
sleep 5
expect "Continue with revocation:"
sleep 3
send -- "yes\\r";
sleep 5
expect "Enter pass phrase for /etc/openvpn/pki/private/ca.key:"
sleep 3
send -- "Ir3hp3sFM30yFFob\\r";
sleep 5
expect "Enter pass phrase for /etc/openvpn/pki/private/ca.key:"
sleep 3
send -- "Ir3hp3sFM30yFFob\\r";
expect eof

EOF

cat > ./openvpn/docker-compose.yml << EOF
version: '2'
services:
  openvpn:
    cap_add:
     - NET_ADMIN
    image: kylemanna/openvpn
    container_name: openvpn
    ports:
     - "1194:1194/udp"
    restart: always
    volumes:
     - ./openvpn-data/conf:/etc/openvpn
EOF

cd ./openvpn

docker-compose run --rm openvpn ovpn_genconfig -u udp://$myip

cat > ./generate-certs.sh << EOF
#!/usr/bin/expect -f

set timeout -1

spawn docker-compose run --rm openvpn ovpn_initpki

expect "Enter New CA Key Passphrase:"
send -- "Ir3hp3sFM30yFFob\\r";
sleep 3

expect "Re-Enter New CA Key Passphrase: "
send -- "Ir3hp3sFM30yFFob\\r";
sleep 3

expect "your user, host, or server name"
sleep 1
send -- "\\r";
sleep 10

expect "Enter pass phrase for /etc/openvpn/pki/private/ca.key:"
send -- "Ir3hp3sFM30yFFob\\r";
sleep 3

expect "Enter pass phrase for /etc/openvpn/pki/private/ca.key:"
send -- "Ir3hp3sFM30yFFob\\r";
sleep 5

expect "CRL file: /etc/openvpn/pki/crl.pem"
expect eof
EOF

expect ./generate-certs.sh

sudo chown -R $(whoami): ./openvpn-data

docker-compose up -d openvpn

Then, run ovpn-install.sh file by running command:bash ovpn-install.sh

After the successful execution of this code, you could add your user by running command bash ./openvpn/addvpnuser.sh {username}

Enjoy!