Validator Guide

Nepher Robotics · Bittensor Subnet 49

This guide walks through deploying a Bittensor Subnet 49 validator using Docker. A single GPU machine runs the complete validator lifecycle: agent evaluation, on-chain weight setting, and burn.

How it works: the validator is a lightweight orchestrator. It downloads miner agents, sets weights on-chain, and spawns a GPU sandbox container (Isaac Sim) on demand to evaluate untrusted agent code in isolation. The sandbox is built once but never runs as a long-lived service — the validator launches it via the host Docker socket. That's why the machine needs a GPU + the NVIDIA Container Toolkit even though the orchestrator itself is light.

No GPU? You can run a CPU-only validator that sets weights but does not evaluate — see the Appendix.

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1. Requirements

Spec	Minimum	Recommended
GPU	RTX A6000 (24 GB VRAM)	A100 (40 GB+)
RAM	32 GB	64 GB+
Disk	100 GB SSD	200 GB+ NVMe
OS	Ubuntu 22.04 LTS	Ubuntu 22.04 LTS
NVIDIA Driver / CUDA	535+ / 12.1+	Latest stable / 12.1+

Software: Docker + Compose, Git. Most GPU cloud providers ship drivers and Docker pre-installed — skip to Step 3 if so.

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2. Server Setup (if needed)

sudo apt update && sudo apt upgrade -y
sudo apt install -y git curl wget build-essential
nvidia-smi  # If this fails, install drivers below

Install NVIDIA drivers

sudo apt install -y nvidia-driver-535 && sudo reboot

Install Docker + NVIDIA Container Toolkit

# Docker
curl -fsSL https://get.docker.com -o get-docker.sh && sudo sh get-docker.sh
sudo usermod -aG docker $USER && newgrp docker
sudo apt install -y docker-compose-plugin

# NVIDIA Container Toolkit
distribution=$(. /etc/os-release;echo $ID$VERSION_ID)
curl -fsSL https://nvidia.github.io/libnvidia-container/gpgkey | sudo gpg --dearmor -o /usr/share/keyrings/nvidia-container-toolkit-keyring.gpg
curl -s -L https://nvidia.github.io/libnvidia-container/$distribution/libnvidia-container.list | \
    sed 's#deb https://#deb [signed-by=/usr/share/keyrings/nvidia-container-toolkit-keyring.gpg] https://#g' | \
    sudo tee /etc/apt/sources.list.d/nvidia-container-toolkit.list
sudo apt update && sudo apt install -y nvidia-container-toolkit
sudo nvidia-ctk runtime configure --runtime=docker && sudo systemctl restart docker

# Verify
docker run --rm --gpus all nvidia/cuda:12.1.0-base-ubuntu22.04 nvidia-smi

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3. Bittensor Wallet

Install the Bittensor CLI (btcli), then register and stake on Subnet 49:

btcli subnet register --wallet.name validator --wallet.hotkey default --netuid 49
btcli stake add       --wallet.name validator --wallet.hotkey default --amount <AMOUNT>

Wallet files live at ~/.bittensor/wallets/validator/.

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4. Get Your Nepher API Key

Sign in at https://account.nepher.ai → API Keys → copy your key.

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5. Configure & Run (Docker)

git clone https://github.com/nepher-ai/nepher-subnet.git && cd nepher-subnet

cp config/docker.env.example .env
cp config/validator_config.example.yaml config/validator_config.yaml

Edit .env (Docker Compose reads these — the wallet directory defaults to ~/.bittensor):

NEPHER_API_KEY=nepher_your_actual_api_key_here
# Optional overrides (sensible defaults ship in docker-compose.yaml):
# BITTENSOR_WALLET_PATH=~/.bittensor
# NEPHER_API_URL=https://tournament-api.nepher.ai

Edit config/validator_config.yaml (read by the validator process — keep it in sync with .env):

tournament:
  api_key: "nepher_your_actual_api_key_here"
wallet:
  name: "validator"
  hotkey: "default"

Shared settings live in config/common_config.yaml (ships with repo) and are merged automatically.

Build the images, then start the validator. The first build is heavy because it builds the GPU sandbox image (Isaac Sim ~20 GB); the validator won't start until it completes:

docker compose build                    # Builds validator + sandbox — 30–60 min first time
docker compose up -d validator          # Starts the orchestrator (spawns sandbox on demand)
docker compose logs -f validator

# Manage
docker compose down                     # Stop
docker compose restart validator        # Restart
docker compose up -d --build validator  # Rebuild after updates
docker compose exec validator bash      # Shell into container

Check status — the validator has a built-in health check (STATUS shows healthy once it's up):

docker compose ps

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Appendix: CPU-Only Validator (weights only)

The validator-cpu service is a stripped-down validator that only sets weights and burns — it does not evaluate agents. Use it if you want to run a valid validator without a GPU. (The full GPU validator from Section 5 already does everything, including weight setting; the CPU service is not a companion to it.)

It runs on a cheap CPU VPS — 2 vCPU · 4 GB RAM · 20 GB disk · Ubuntu 22.04 — with no GPU, no Isaac Sim, and a lightweight image (~200 MB). It uses the same wallet, config, and .env setup as the GPU validator (Steps 3–5).

docker compose build validator-cpu && docker compose up -d validator-cpu
docker compose logs -f validator-cpu

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Need Help?

• Docs: https://docs.nepher.ai
• Discord: https://discord.gg/nepher
• Issues: https://github.com/nepher-ai/nepher-subnet/issues