a2enmod ssl
a2enmod proxy  
a2enmod proxy_http  
a2enmod proxy_wstunnel  
vi /etc/apache2/sites-available/default-ssl.conf

<IfModule mod_ssl.c>
  <VirtualHost _default_:443>
    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html
    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
    SSLEngine on
    SSLCertificateFile /etc/letsencrypt/live/{ドメイン名}/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/{ドメイン名}/privkey.pem
	ProxyPass /ws ws://localhost:8000/ws nocanon
	ProxyPass / http://localhost:8000/ nocanon
	ProxyPassReverse /ws ws://localhost:8000/ws
	ProxyPassReverse / http://localhost:8000/
    <FilesMatch "\.(cgi|shtml|phtml|php)$">
        SSLOptions +StdEnvVars
    </FilesMatch>
    <Directory /usr/lib/cgi-bin>
        SSLOptions +StdEnvVars
    </Directory>
  </VirtualHost>
</IfModule>

systemctl restart apache2