I’ve seen several variations of this question recently. Usually there’s some confusion about “Arnold standalone” and what’s actually required on a render node.

If you rendering scene files from Maya, or 3ds Max, or some other 3d application, then you do not need Arnold standalone.

You need the 3d application (Maya, 3ds Max) and the Arnold plugin for that application (MtoA, MAXtoA). Download the Arnold plugin from https://www.arnoldrenderer.com/arnold/download

For example, let’s suppose you want to render Maya scene files.

• You need to install Maya and MtoA on each render node.
• You don’t need Maya licenses for batch rendering, and you don’t need Maya licenses to install Maya on render nodes.
• You need Arnold licenses, which are a separate purchase. MtoA is free and unlicensed. Arnold, however, does require a license to render without the watermark. You need one Arnold license for each render node (for you CINEMA 4D users, a TeamRender client is an Arnold render node and requires its own license).
• You need an Autodesk network license server running somewhere (not on a render node).
• You need to connect Arnold to the Autodesk network license manager.

It’s the same thing for 3ds Max and MAXtoA.