Radarr is part of the Servarr suite: it allows to automatically organize, search and download movies.

You will need Radarr if you plan to organize and enrich your movies collection. Note that Radarr can only manage either movies up to 1080p or 4K. If you want to have both the same movie up to 1080p and in 4K at the same time, you will need to start two instances of Radarr at the same time. More information on this approach can be deducted from the Readarr setup, where you will be running two instances of an *Arr at the same time.

Radarr is easily installed and managed within Gentoo linux since there is an ebuild for it. All you need to do is unmask it (at the time of writing this it's are masked for AMD64 at least):

echo www-apps/radarr ~amd64 >> /etc/portage/package.accept_keywords/radarr

then install it:

emerge -v radarr

This step will create a dedicated radarr user but you will want to add it to the group media, that you have created before, so that the it will be able to access and manage your media collection:

usermod -a -G media radarr

Also, you want to move Radarr home folder under /data/daemons/radarr for consistency and to be protected on the RAID array, so:

usermod -m -d /data/daemons/radarr radarr

Before you proceed, you should make Radarr accessible via the reverse-proxy, so that access, configuration and usage will be simplified from the beginning. Add this file to /etc/nginx/folders:

radarr.conf

# Radarr - films
location ^~ /radarr {
        proxy_pass http://127.0.0.1:7878;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_redirect off;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $http_connection;
}
# Allow the API External Access via NGINX
location ^~ /radarr/api {
        auth_basic off;
        proxy_pass http://127.0.0.1:7878;
}

Refer to The Reverse Proxy concept on how to add this config and reload the Reverse Proxy.

There are some configuration that must be perform before actually starting the service. You need to briefly start and stop it to let it create the main configuration file, this is required because you need to generate a new API key:

/etc/init.d/radarr start
/etc/init.d/radarr stop

Now edit the newly created xml config file /data/daemons/radarr/.config/Radarr and edit the UrlBase to match the reverse-proxy setup. Only change the following lines in the file, do not edit anything else (unless you know what you are doing):

  <UrlBase>radarr</UrlBase>
    <BindAddress>127.0.0.1</BindAddress>
  <AuthenticationMethod>Forms</AuthenticationMethod>
  <AuthenticationRequired>DisabledForLocalAddresses</AuthenticationRequired>

Add Radarr to default runlevel, for autostart on reboot, and start it manually now:

rc-update add radarr default
/etc/init.d/radarr start

Radarr will now be accessible as http://192.168.0.1/radarr.

All set! Radarr is running.

In order for Radarr to benefit from Prowlarr automatic indexers management you need to open http://192.168.0.1/prowlarr in your browser, go to settings → apps and add Radarr. From the popup window set:

• Radar server: http://localhost:7878/radarr
• API Key: grab it from Radarr settings → general page and paste it here

Then go to the Prowlarr indexers page and click on the synchronize all indexers icon.

Before you can actually use Radarr you need to perform some initial setup in settings → media management:

• Add a new Root Folder. Use /data/Movies as root folder.

Now enable “advanced settings” and:

• Thick “Set permissions” to on
• Set “chmod folder” to 775 (umask will be 0002)
• set “chmod Group” to “media”
• save and restart the daemon (from the user icon on top-right corner)

you can fine tune and configure many other aspects of Radarr as you wish. A very common guide is The TRaSH Guides.

Please note that you will not yet be able to use Radarr fully as you have not yet installed any downloader.