Access your Cockpit by domain within a Reverse proxy setup with Apache2

Short tutorial about how to config your Cockpit instance to be accessed by domain instead of IP address.

If you don't know Cockpit yet it is a "Cockpit is a web-based graphical interface for servers" that helps you to manage your web server via Web.

Prerequisites

• A server running with an Apache2 site
• A reverse proxy setup with an existing Cockpit instance

Hands on 🙌

Create or add to your /etc/cockpit/cockpit.conf the following lines:

[WebService]
Origins = https://somedomain1.com https://somedomain2.com:9090

Restart cockpit service with:

sudo systemctl restart cockpit

Edit your Apache2 site.conf (for example sudo nano /etc/apache2/sites-enabled/cockpit.your-domain.com-le-ssl.conf) so it looks like the following:

<IfModule mod_ssl.c>
<VirtualHost *:443>
  ServerName cockpit.your-domain.com
  SSLCertificateFile /etc/letsencrypt/live/cockpit.your-domain.com/fullchain.pem
  SSLCertificateKeyFile /etc/letsencrypt/live/cockpit.your-domain.com/privkey.pem
  Include /etc/letsencrypt/options-ssl-apache.conf

  ProxyPreserveHost On
  ProxyRequests Off

  # allow for upgrading to websockets
  RewriteEngine On
  RewriteCond %{HTTP:Upgrade} =websocket [NC]
  RewriteRule /(.*)           ws://127.0.0.1:9090/$1 [P,L]
  RewriteCond %{HTTP:Upgrade} !=websocket [NC]
  RewriteRule /(.*)           http://127.0.0.1:9090/$1 [P,L]

  # Proxy to your local cockpit instance
  ProxyPass / http://127.0.0.1:9090/
  ProxyPassReverse / http://127.0.0.1:9090/
</VirtualHost>
</IfModule>

the important part is the Rewrite section for upgrading Websockets.

Lastly reloads Apache2 service by sudo systemctl reload apache2

Sources

• Cockpit docs about cockpit.conf here.
• Reverse proxy in a subdomain configuration with Cockpit here.
• Github issue/question about this setup here.