Host Anvil Documentation
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Headless Client Support

Host Anvil supports free headless client (HC) deployment for all Arma 3 servers. Headless clients help offload AI and script-heavy computations from the main server thread, drastically improving performance in large-scale or persistent missions.

What Is a Headless Client?

A headless client is a lightweight Arma 3 instance that connects to your main server but doesn't render graphics or participate as a player. Instead, it:

  • Handles AI units and pathfinding
  • Executes complex mission scripts or mods
  • Frees up resources on the main server for networking and syncing players

Using one or more HCs significantly reduces desync and CPU bottlenecks, especially for high-pop or AI-intensive missions.

Included with Your Server

  • Up to 5 headless clients included for free
  • You can run as many HCs as your server’s CPU and RAM allocation can support
  • No extra billing or hidden resource charges
TIP

If you're unsure how many HCs your setup can handle, start with 1–2 and monitor usage in the panel.

Setting It Up

1. Add the Headless Client Token

In your mission .sqf or .sqm, configure the HC using:

if (isServer) then {
  _group = createGroup east;
  _unit = _group createUnit ["O_Soldier_F", getMarkerPos "spawn", [], 0, "NONE"];
  _unit setVariable ["HC_AI", true];
};

And in your server config:

headlessClients[] = {"127.0.0.1"};
localClient[] = {"127.0.0.1"};

If you are using multiple HCs, list each by IP.

2. Start the Headless Client(s)

Start each HC with:

./arma3server_x64 -client -connect=127.0.0.1 -mod="@ace;@rhs" -password=yourserverpass

This connects the HC to your server locally.

3. Confirm Connection

You can verify HC connections via:

  • The in-game admin panel (shows HC in the player list)
  • Your panel’s live logs or console output
  • RCON (will show HC as a connected player with no ping)

HC Tips

  • Place AI-heavy scripts and groups under if (isHC) then {} blocks
  • Use multiple HCs for complex co-op missions or Zeus gameplay
  • Avoid assigning mods or scripts that require UI interaction to the HC

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