Step 1: Download and Install Domain Booster Plugin
You can install Domain Booster Plugin directly from Confluence using Confluence Plugin Manager. Alternatively, download it directly from Atlassian Marketplace and then upload to Confluence.
With the initial Domain Booster configuration you should not see any differences in how Confluence serves your content.
Site 2: Configure Proxy and update DNS for New Site(s)
If you're running Confluence behind a proxy, create a configuration for your new site. You can use the official Confluence documentation for this.
Example proxied site configuration for Apache
<VirtualHost *:80>
ServerName newsite.mydomain.com
HostnameLookups off
ProxyRequests off
ProxyPreserveHost On
ProxyPass / http://docs.mydomain.com:8090/ timeout=35
ProxyPassReverse / http://docs.mydomain.com:8090/
<Proxy *>
Order allow,deny
Allow from all
</Proxy>
</VirtualHost>
If you were modifying Tomcat's server.xml to specify proxyName and proxyPort, you can do that now in Domain Booster configuration in Site Settings.
Finally, you should make necessary changes to your DNS server so that new site names point to your proxy (or Confluence).
Step 3: Define New Site in Domain Booster Configuration Panel
Sign-in to Confluence as Administrator, go to Confluence Admin and click Domain Booster Configuration.