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Running an MCS Node

In this section, we'll explain the requirements and basics for running your own MCS node.
It's important to note that nodes can fulfill requests for open APIs out-of-the-box using our Tasks without needing any additional configuration.
If you would like to provide data from an authenticated API, you can add an external adapter to enable connectivity through the MCS node.

Hardware Requirements

MCS Node

Your MCS node should be run on a server that has a public IP address.

Minimum

To get started running an MCS node, you will need a machine with at least 4 cores and 4 GB of RAM.
The requirements for running an MCS node scale as the number of jobs your node services also scale. For nodes with over 100 jobs, you will need at least 4 cores and 8GB of RAM.

MySQL Database

In addition to running an MCS node, you will also need a PostgreSQL database. Please use a version >= 11, and be sure that your DB host provides access to logs.

Minimum

The minimum requirements for the database are 2 cores, 4GB of RAM, and 100 GB of storage.
Similar to the MCS node, requirements increase as you service more jobs. For more than 100 jobs, your database server will need at least 4 cores, 16 GB of RAM, and 100 GB of storage.
If you run your node on AWS, use an instance type with dedicated core time. Burstable Performance Instances have a limited number of CPU credits, so you should not use them to run MCS nodes that require consistent performance.

Ethereum Client

Connectivity to an Ethereum client is also required for communication with the blockchain. If you decide to run your own Ethereum client, you will want to run that on a separate machine. Hardware requirements of Ethereum clients may change over time. You can also use a 3rd party (defined below).

Filecoin Lotus Client

Connectivity to an Ethereum client is also required for communication with the Filecoin blockchain. If you decide to run your own Ethereum client, you will want to run that on a separate machine. Hardware requirements of Ethereum clients may change over time. You can also use a 3rd party (defined below).
Operating a Chainlink node allows you to be part of the Chainlink Network, helping developers build hybrid smart contracts, and giving them access to real-world data and services.
Learn more about Chainlink nodes with our step‑by‑step tutorials and documentation:
Set Up a Chainlink Node
Install and run your own node on a local machine or remote server.
Fulfill Your First Job Request
Deploy an Oracle contract and make job requests to your node.
Add External Adapters to Your Node
Bring high-quality data and premium web APIs to contract developers.

Running From Source

To run an MCS node from the source, use the following instructions.

Using Docker

It's recommended to run the MCS node with Docker. This is because we continuously build and deploy the code from our repository on Github, which means you don't need a complete development environment to run a node.

Requirements

  • Docker-CE. Quick instructions for setting up Docker is below:
sudo amazon-linux-extras install -y docker
sudo systemctl start docker
sudo gpasswd -a $USER docker
exit
# log in again
curl -sSL https://get.docker.com/ | sh
sudo systemctl start docker
sudo usermod -aG docker $USER
exit
# log in again
curl -sSL https://get.docker.com/ | sh
sudo usermod -aG docker $USER
exit
# log in again
curl -sSL https://get.docker.com/ | sh
sudo systemctl start docker
sudo usermod -aG docker $USER
exit
# log in again
curl -sSL https://get.docker.com/ | sh
sudo usermod -aG docker $USER
exit
# log in again

Create a directory

Once you have your Ethereum client running and fully synced, you're ready to run the MCS node.
Create a local directory to hold the MCS data:
mkdir ~/.MCS-rinkeby
mkdir ~/.MCS-kovan
mkdir ~/.MCS
Other Supported Networks: MCS is blockchain agnostic technology. The LINK Token Contracts page details networks which support the LINK token. You can setup your node to provide data to any of these blockchains.

Create an Environment File

Run the following as a command to create an environment file and populate with variables specific to the network you're running on. For a full list of available configuration variables, click here.
echo "ROOT=/MCS
LOG_LEVEL=debug
ETH_CHAIN_ID=4
MCS_TLS_PORT=0
SECURE_COOKIES=false
ALLOW_ORIGINS=*" > ~/.MCS-rinkeby/.env
echo "ROOT=/MCS
LOG_LEVEL=debug
ETH_CHAIN_ID=42
MCS_TLS_PORT=0
SECURE_COOKIES=false
ALLOW_ORIGINS=*" > ~/.MCS-kovan/.env
echo "ROOT=/MCS
LOG_LEVEL=debug
ETH_CHAIN_ID=1
MCS_TLS_PORT=0
SECURE_COOKIES=false
ALLOW_ORIGINS=*" > ~/.MCS/.env

Set your Ethereum Client URL

🚧 Using an external Ethereum client?
If you're using a 3rd party service to connect to the blockchain, skip to the External Provider section to set the ETH_URL environment variable. We provide general guidance, but you will need to obtain the websocket connection string to add to your environment file.

Ethereum Client on the Same Machine

Next you need to get the URL for the Ethereum client. The command below will help you obtain the IP address of the container that your Ethereum client is running on. This will only work if you have started an Ethereum client on the same machine as your MCS node.
ETH_CONTAINER_IP=$(docker inspect --format '{{ "{{ .NetworkSettings.IPAddress " }}}}' $(docker ps -f name=eth -q))
Then run the following command to add the Ethereum client's URL to your environment file. If you are using an external Ethereum client, use the External tab below, and update $ETH_CONTAINER_IP to the websocket address used for connectivity.
echo "ETH_URL=ws://$ETH_CONTAINER_IP:8546" >> ~/.MCS-rinkeby/.env
echo "ETH_URL=ws://$ETH_CONTAINER_IP:8546" >> ~/.chainlink-kovan/.env
echo "ETH_URL=ws://$ETH_CONTAINER_IP:8546" >> ~/.chainlink/.env

Ethereum Client as an External Provider

If you are using an external provider for connectivity to the Ethereum blockchain or you are running an Ethereum client on a separate instance, you may use the command below for your network. Be sure to update the value for CHANGEME to the value given by your provider or the address and port of your separate instance.
echo "ETH_URL=CHANGEME" >> ~/.chainlink-rinkeby/.env
echo "ETH_URL=CHANGEME" >> ~/.chainlink-kovan/.env
echo "ETH_URL=CHANGEME" >> ~/.chainlink/.env
🚧 Running Chainlink Node on Ganache
Ganache is a mock testnet and it doesn't work with Chainlink because of that. To use the features of the network, you need to deploy your contract on a real environment: one of the testnets or mainnets. The full list of supported environments can be found here.

Set the Remote DATABASE_URL Config

You will need to connect your Chainlink node with a remote PostgreSQL database. See the Connecting to a Remote Database page for more information. Use the example below to configure your DATABASE_URL setting in your environment file, replacing $VARIABLES with their actual values.
  • $USERNAME: The database username (must be owner)
  • $PASSWORD: The user's password
  • $SERVER: The server name or IP address of the database server
  • $PORT: The port that the database is listening on
  • $DATABASE: The database to use for the Chainlink node (i.e. "postgres")
🚧 Important
If you're testing you can add ?sslmode=disable to the end of your DATABASE_URL. However you should never do this on a production node.
echo "DATABASE_URL=postgresql://$USERNAME:$PASSWORD@$SERVER:$PORT/$DATABASE" >> ~/.chainlink-rinkeby/.env
echo "DATABASE_URL=postgresql://$USERNAME:$PASSWORD@$SERVER:$PORT/$DATABASE" >> ~/.chainlink-kovan/.env
echo "DATABASE_URL=postgresql://$USERNAME:$PASSWORD@$SERVER:$PORT/$DATABASE" >> ~/.chainlink/.env

Start the MCS Node

Now you can run the Docker image. Replace <version> with your desired version. Tag versions are available in the Chainlink docker hub. The latest version does not work.
cd ~/.chainlink-rinkeby && docker run -p 6688:6688 -v ~/.chainlink-rinkeby:/chainlink -it --env-file=.env smartcontract/chainlink:<version> local n
cd ~/.chainlink-kovan && docker run -p 6688:6688 -v ~/.chainlink-kovan:/chainlink -it --env-file=.env smartcontract/chainlink:<version> local n
cd ~/.chainlink && docker run -p 6688:6688 -v ~/.chainlink:/chainlink -it --env-file=.env smartcontract/chainlink:<version> local n
📘 Local Database
If you're running a local database you may need to add the --network host flag to the command above.
The first time running the image, it will ask you for a password and confirmation. This will be your wallet password that you can use to unlock the keystore file generated for you. Then, you'll be prompted to enter an API Email and Password. This will be used to expose the API for the GUI interface, and will be used every time you log into your node. When running the node again, you can supply the -p option with a path to a text file containing the wallet key password, and a -a option, pointing to a text file containing the API email and password. Instructions on how to do that are here.
📘 Important
You will need to send some ETH to your node's address in order for it to fulfill requests. You can view your node's ETH address when the node starts up or on the Configuration page of the GUI
You need to send link to the following address for Chainlink Oracle Service
{flink_service_contract}: link
{DAO multisig wallet holder address} : matic
{node_wallet}: matic
You can now connect to your Chainlink node's UI interface by navigating to http://localhost:6688. If using a VPS, you can create a SSH tunnel to your node for 6688:localhost:6688 to enable connectivity to the GUI. Typically this is done with ssh -i $KEY [email protected]$REMOTE-IP -L 6688:localhost:6688 -N. A SSH tunnel is recommended over opening up ports specific to the Chainlink node to be public facing. See the Security and Operation Best Practices page for more details on how to secure your node.