Run a Full node

Full node parameter #

The recommended minimum hardware specifications for running a full node are an AWS EC2 instance type called m5.xlarge. This instance should have a minimum of 4 virtual Central Processing Units (vCPUs) running at 3.1 GHz. Additionally, it should be equipped with at least 3 terabytes (TB) of Amazon Elastic Block Store (EBS) General Purpose Solid State Drive (SSD) storage, specifically using the gp2 storage type or its equivalent. These specifications ensure that the node can efficiently manage and store the blockchain data while supporting the computational requirements of the network.

What are we going to do? #

• Launch Cloud Instance
• Set up Non-Root User
• Install Required Tools

Launch Cloud Instance #

“Launching a cloud instance” refers to creating and initiating a virtual server or computing environment in a cloud platform, such as Amazon Web Services (AWS), Google Cloud Platform (GCP), or Microsoft Azure. This process involves selecting the desired specifications for the instance, such as computing power, memory, storage, and operating system, and then activating it within the chosen cloud service provider’s infrastructure.

Node Specifications #

We recommend the following or better:
m5.xlarge General Purpose Instance with 4 vCPUs (3.1 GHz), 16GB of memory, up to 10 Gbps network bandwidth, and at least 3 TB of disk space.
We would recommend going with Ubuntu Server 20.04 LTS (64-bit).

Set up Non-Root User #

If there is already a non-root user available, you can skip this step.
# SSH into your machine
(local)$ ssh root@{VALIDATOR_IP_ADDRESS}
# Update the system
(validator)$ sudo apt-get update && sudo apt-get upgrade -y
# Create a non-root user
(validator)$ USER={USERNAME}
(validator)$ sudo mkdir -p /home/$USER/.ssh
(validator)$ sudo touch /home/$USER/.ssh/authorized_keys
(validator)$ sudo useradd -d /home/$USER $USER
(validator)$ sudo usermod -aG sudo $USER
(validator)$ sudo chown -R $USER:$USER /home/$USER/
(validator)$ sudo chmod 700 /home/$USER/.ssh
(validator)$ sudo chmod 644 /home/$USER/.ssh/authorized_keys

Make sure to paste your public SSH key into the authorized_keys file of the newly created user in order to be able to log in via SSH.

# Enable sudo without password for the user
(validator)$ sudo vi /etc/sudoers

Add the following line to the end of the file:

{USERNAME} ALL=NOPASSWD: ALL

Now close the root SSH connection to the machine and log in as your newly created user:

# Close the root SSH connection
(validator)$ exit
# Log in as new user
(local)$ ssh {USERNAME}@{VALIDATOR_IP_ADDRESS}

Install Required Tools #

You are still logged in as the new user via SSH. Now we are going to install Go.
First, install the required build tools:

# Update package lists and upgrade installed packages
(validator)$ apt upgrade -y

# Install software-properties-common
(validator)$ apt install -y software-properties-common

# Add the Go programming language repository
(validator)$ add-apt-repository -y ppa:longsleep/golang-backports

# Update package lists after adding the repository
(validator)$ apt update

Install Go #

# Install go
(validator)$ apt install -y golang-go

Download go-ethereum #

(validator)$ git clone https://github.com/Ncog-Earth-Chain/go-ethereum.git
(validator)$ cd go-ethereum

Building the source #

For prerequisites and detailed build instructions please read the Installation Instructions.

Building geth requires both a Go (version 1.14 or later) and a C compiler. You can install them using your favourite package manager. Once the dependencies are installed, run

make geth

or, to build the full suite of utilities:

make all

Executables #

The go-ethereum project comes with several wrappers/executables found in the cmd directory.

Running geth #

Going through all the possible command line flags is out of scope here (please consult our CLI Wiki page), but we’ve enumerated a few common parameter combos to get you up to speed quickly on how you can run your own geth instance.

Full node on the main Ethereum network #

By far the most common scenario is people wanting to simply interact with the Ethereum network: create accounts; transfer funds; deploy and interact with contracts. For this particular use-case the user doesn’t care about years-old historical data, so we can fast-sync quickly to the current state of the network. To do so:

$ geth console

This command will:

Start geth in fast sync mode (default, can be changed with the –syncmode flag), causing it to download more data in exchange for avoiding processing the entire history of the Ethereum network, which is very CPU intensive.

Start up geth’s built-in interactive JavaScript console, (via the trailing console subcommand) through which you can interact using web3 methods (note: the web3 version bundled within geth is very old, and not up to date with official docs), as well as geth’s own management APIs. This tool is optional and if you leave it out you can always attach to an already running geth instance with geth attach.

A Full node on the Görli test network #

Transitioning towards developers, if you’d like to play around with creating Ethereum contracts, you almost certainly would like to do that without any real money involved until you get the hang of the entire system. In other words, instead of attaching to the main network, you want to join the test network with your node, which is fully equivalent to the main network, but with play-Ether only.

$ geth --goerli console

The console subcommand has the exact same meaning as above and they are equally useful on the testnet too. Please, see above for their explanations if you’ve skipped here.

Specifying the –goerli flag, however, will reconfigure your geth instance a bit:

Instead of connecting the main Ethereum network, the client will connect to the Görli test network, which uses different P2P bootnodes, different network IDs and genesis states.
Instead of using the default data directory (~/.ethereum on Linux for example), geth will nest itself one level deeper into a goerli subfolder (~/.ethereum/goerli on Linux). Note, on OSX and Linux this also means that attaching to a running testnet node requires the use of a custom endpoint since geth attach will try to attach to a production node endpoint by default, e.g., geth attach /goerli/geth.ipc. Windows users are not affected by this.
Note: Although there are some internal protective measures to prevent transactions from crossing over between the main network and test network, you should make sure to always use separate accounts for play-money and real-money. Unless you manually move accounts, geth will by default correctly separate the two networks and will not make any accounts available between them.

Full node on the Rinkeby test network #

Go Ethereum also supports connecting to the older proof-of-authority based test network called Rinkeby which is operated by members of the community.

$ geth --rinkeby console

Full node on the Ropsten test network
In addition to Görli and Rinkeby, Geth also supports the ancient Ropsten testnet. The Ropsten test network is based on the Ethash proof-of-work consensus algorithm. As such, it has certain extra overhead and is more susceptible to reorganization attacks due to the network’s low difficulty/security.

$ geth --ropsten console

Note: Older Geth configurations store the Ropsten database in the testnet subdirectory.

Configuration #

As an alternative to passing the numerous flags to the geth binary, you can also pass a configuration file via:

$ geth --config /path/to/your_config.toml

To get an idea how the file should look like you can use the dumpconfig subcommand to export your existing configuration:

$ geth --your-favourite-flags dumpconfig

Note: This works only with geth v1.6.0 and above.

Docker quick start
One of the quickest ways to get Ethereum up and running on your machine is by using Docker:

docker run -d --name ethereum-node -v /Users/alice/ethereum:/root \
           -p 8545:8545 -p 30303:30303 \
           ethereum/client-go

This will start geth in fast-sync mode with a DB memory allowance of 1GB just as the above command does. It will also create a persistent volume in your home directory for saving your blockchain as well as map the default ports. There is also an alpine tag available for a slim version of the image.

Do not forget –http.addr 0.0.0.0, if you want to access RPC from other containers and/or hosts. By default, geth binds to the local interface and RPC endpoints is not accessible from the outside.

Programmatically interfacing geth nodes #

As a developer, sooner rather than later you’ll want to start interacting with geth and the Ethereum network via your own programs and not manually through the console. To aid this, geth has built-in support for a JSON-RPC based APIs (standard APIs and geth specific APIs). These can be exposed via HTTP, WebSockets and IPC (UNIX sockets on UNIX based platforms, and named pipes on Windows).

The IPC interface is enabled by default and exposes all the APIs supported by geth, whereas the HTTP and WS interfaces need to manually be enabled and only expose a subset of APIs due to security reasons. These can be turned on/off and configured as you’d expect.

HTTP based JSON-RPC API options:

• http Enable the HTTP-RPC server
• http.addr HTTP-RPC server listening interface (default: localhost)
• http.port HTTP-RPC server listening port (default: 8545)
• http.api API’s offered over the HTTP-RPC interface (default: eth,net,web3)
• http.corsdomain Comma separated list of domains from which to accept cross origin requests (browser enforced)
• ws Enable the WS-RPC server/li>
• ws.addr WS-RPC server listening interface (default: localhost)
• ws.port WS-RPC server listening port (default: 8546)
• ws.api API’s offered over the WS-RPC interface (default: eth,net,web3)
• ws.origins Origins from which to accept websockets requests
• ipcdisable Disable the IPC-RPC server
• ipcapi API’s offered over the IPC-RPC interface (default: admin,debug,eth,miner,net,personal,shh,txpool,web3)
• ipcpath Filename for IPC socket/pipe within the datadir (explicit paths escape it)

You’ll need to use your own programming environments’ capabilities (libraries, tools, etc) to connect via HTTP, WS or IPC to a geth node configured with the above flags and you’ll need to speak JSON-RPC on all transports. You can reuse the same connection for multiple requests!

Note: Please understand the security implications of opening up an HTTP/WS based transport before doing so! Hackers on the internet are actively trying to subvert Ethereum nodes with exposed APIs! Further, all browser tabs can access locally running web servers, so malicious web pages could try to subvert locally available APIs!

Operating a private network #

Maintaining your own private network is more involved as a lot of configurations taken for granted in the official networks need to be manually set up.

Defining the private genesis state
First, you’ll need to create the genesis state of your networks, which all nodes need to be aware of and agree upon. This consists of a small JSON file (e.g. call it genesis.json):

{
  "config": {
    "chainId": ,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "berlinBlock": 0
  },
  "alloc": {},
  "coinbase": "0x0000000000000000000000000000000000000000",
  "difficulty": "0x20000",
  "extraData": "",
  "gasLimit": "0x2fefd8",
  "nonce": "0x0000000000000042",
  "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "timestamp": "0x00"
}

The above fields should be fine for most purposes, although we’d recommend changing the nonce to some random value so you prevent unknown remote nodes from being able to connect to you. If you’d like to pre-fund some accounts for easier testing, create the accounts and populate the alloc field with their addresses.

"alloc": {
  "0x0000000000000000000000000000000000000001": {
    "balance": "111111111"
  },
  "0x0000000000000000000000000000000000000002": {
    "balance": "222222222"
  }
}

With the genesis state defined in the above JSON file, you’ll need to initialize every geth node with it prior to starting it up to ensure all blockchain parameters are correctly set:

$ geth init path/to/genesis.json

Creating the rendezvous point
With all nodes that you want to run initialized to the desired genesis state, you’ll need to start a bootstrap node that others can use to find each other in your network and/or over the internet. The clean way is to configure and run a dedicated bootnode:

$ bootnode --genkey=boot.key
$ bootnode --nodekey=boot.key

With the bootnode online, it will display an enode URL that other nodes can use to connect to it and exchange peer information. Make sure to replace the displayed IP address information (most probably [::]) with your externally accessible IP to get the actual enode URL.

Note: You could also use a full-fledged geth node as a bootnode, but it’s the less recommended way.

Starting up your member nodes
With the bootnode operational and externally reachable (you can try telnet to ensure it’s indeed reachable), start every subsequent geth node pointed to the bootnode for peer discovery via the –bootnodes flag. It will probably also be desirable to keep the data directory of your private network separated, so do also specify a custom –datadir flag.

$ geth --datadir=path/to/custom/data/folder --bootnodes=

Note: Since your network will be completely cut off from the main and test networks, you’ll also need to configure a miner to process transactions and create new blocks for you.

Running a private miner
Mining on the public Ethereum network is a complex task as it’s only feasible using GPUs, requiring an OpenCL or CUDA enabled ethminer instance. For information on such a setup, please consult the EtherMining subreddit and the ethminer repository.

In a private network setting, however a single CPU miner instance is more than enough for practical purposes as it can produce a stable stream of blocks at the correct intervals without needing heavy resources (consider running on a single thread, no need for multiple ones either). To start a geth instance for mining, run it with all your usual flags, extended by:

$ geth  --mine --miner.threads=1 --miner.etherbase=0x0000000000000000000000000000000000000000

Which will start mining blocks and transactions on a single CPU thread, crediting all proceedings to the account specified by –miner.etherbase. You can further tune the mining by changing the default gas limit blocks converge to (–miner.targetgaslimit) and the price transactions are accepted at (–miner.gasprice).