Running Watchtower: for DePIN/Validator Node provider

Steps to run a Witness Chain watchtower client (PoL Challenger Client)

The PoL Challenger Client Node is a DePIN Challenger node that participates in the PoL (Proof-of-Location) protocol and measures the location claims made by a DePIN Prover.

PoL Challenger Client Nodes can be run on community members’ laptops, desktops or even on cloud instances. As long as the node is running, there is a probabilistic algorithm (based on stake in the upcoming releases) that determines if the node will participate in a PoL challenge from the network.

Before a node can participate as PoL Challenger, it has to prove it's own capabilities (run a prover to prove it's own location - this mechanism is inbuilt in the challenger client container)

Prerequisites

Before you begin, ensure you have the following

• Docker (version 23.0.0 or above, refer: https://docs.docker.com/desktop/install/linux-install/)

• Instance comparable to a t2 micro (1 vcpu, 1GB RAM and 5GB harddisk), though we recommend 2 cores, 4 GB RAM and 10 GB of storage.

Running your Challenger client

Explorer: https://blue-orangutan-blockscout.eu-north-2.gateway.fm/

Our chain is gasless, so you do NOT have to fund either or the operator or challenger account with tokens.

Key Points to consider before proceeding...

Note: For EigenLayer operators, it's important to maintain the distinction between Operator Key and Challenger Key. Refer the correct docs for setup as an EL operator here

1. Generate a dedicated watchtower key - ECDSA KeyPair ( This video demonstrates how you can use MetaMask to export one ). This will be used for registration & signing purposes.

2. Ports to be opened if using public IP:

Incoming ports to be opened (TCP & UDP ):

11112
22223
33334
33335
33336
44445
44446
44447
55556

Outgoing ports: Allow all

1. Registering the Watchtower Key

Download and install the witness CLI:

curl -sSfL https://witnesschain-com.github.io/install-dcl-cli | bash

After the installation is completed, register your watchtower key on WitnessChain's Layer 2 Chain: Use the KeyPair that you would have exported or created using Metamask or any other wallet.

witness-cli registerWatchtower --testnet --watchtower-private-key <your-watchtower-private-key-without-0x-prefix>

Why should I register?

Registration helps with identification of your watchtower inside Witness Chain's watchtower network

2. Setting up the Watchtower keys and the config file

Use ECDSA Keypairs

1. You can pass the required configuration to the docker container env via a file or directly with -e flag in the run command (read more). Prepare a configuration file watchtower.env with the following entries as example shown below:

latitude=37.01511676489697
longitude=-79.0392271449855
country=US
region=Virginia
city=Ashburn
radius=1000
privateKey=<my_super_secret_private_key>
walletPublicKey=<my_open_public_address>
keyType=ethereum
saveResultsInDatabase=false
submitResultsToContract=true
rpcUrl=https://blue-orangutan-rpc.eu-north-2.gateway.fm
projectName=<my_DePIN_project_name/my_validator_network_name>

Explanation:

•  
      "latitude": 37.015, // Required. Latitude of the machine running the challenger client
      "longitude": -79.039, // Required. Longitude of the machine running the challenger client
      
      "country": "US", // Optional. Country in which the machine is located
      "region": "Virginia", // Optional. State/Region in which the machine is located
      "city": "Ashburn", // Optional. City in which the machine is located
      "radius": 1000 // Optional. Accuracy in meters
      

• privateKey is your PoL signing key (Watchtower/Challenger Key)

• walletPublicKey is the wallet addresses where your contributions go

• havePublicIPv4Address (and havePublicIPv6Address) set them to true if you have a public IPv4 (or IPv6)

• havePrivateIPv4Address (and havePrivateIPv6Address) set them to true if you want to force the use of private IP

• saveResultsInDatabase saves the login, session, and challenge related data in a .sqlite file within the container

• projectName tags the watchtower with the project - examples include "spheron", "akash", "pingpong", "eigenlayer", etc. This is an optional field

3. Running the watchtower

Once you have the watchtower.env ready, the watchtower client can be started with

docker run -d \
  --network=host \
  --name pol-challenger \
  --env-file ./watchtower.env \ 
  witnesschain/pol-challenger:0.3.5-alpha

you can verify that the challenger is running by looking at the container status

docker ps 

Explanation:

1. docker run -d: Runs the container in detached mode (in the background).

   • --network=host
     Uses the host's network stack.

   • --name pol-challenger
     Names the container as 'pol-challenger'.

   • --env-file ./watchtower.env
     The container's environment is set using the attributes specified in 'watchtower.env' file

   • witnesschain/pol-challenger:0.3.5-alpha: The name of the Docker image to run.

You may observe the following errors in the docker container

"registration is required on DCL contract. Please register your challenger publicKey:"

Don't worry, this is normal. if you COMPLETE STEP 1, these logs should disappear

Post Setup

Once the setting up and registration is successful, you can check the logs from the challenger client ready for challenges. (docker logs pol-challenger). Congratulations, you are now a part of our DePIN family!

Troubleshooting

As the only prerequisite is docker, make sure you are running atleast version 23.0.0 or above for the commands mentioned in the doc to work. The days might be rainy or snowy, but we've got umbrellas and sweaters! Join our Discord or reach out to us over Telegram—we're happy to help. :D