Blendnet is a network rendering farm system for Blender that dynamically allocates the resources a render needs on a cloud provider, or automates an existing render farm. The developer describes it as free, secure, and quite well optimised to work with minimal delays. Automating a private farm infrastructure is also possible, though it currently requires some adjustment.
While a job runs, a dynamic preview shows rendering progress, with the picture updated every five seconds by default. The preview engine is non-destructive, so you can close the preview and open it again without interrupting the render. Providers can be created for GCP, AWS, and Local, and when there are no tasks the render workers are terminated.
Blendnet is free software that anyone can use or modify, with the addon available to download from GitHub. It supports Blender versions 2.8 through 3.0 and is listed here under a royalty-free license. A demo video is available.