wget https://dl.eff.org/certbot-auto &&\
mv certbot-auto /usr/local/bin/ &&\
chown root:root /usr/local/bin/certbot-auto &&\
chmod 0755 /usr/local/bin/certbot-auto

See certbot installation

• Letsencrypt certificate via DNS authentication
• Setup certificate on servers without root access

• https://certbot.eff.org/docs/install.html#certbot-auto