Running An Ethereum Node Part One

10 Nov 2021

Why Run an Ethereum Node?
Installing Geth
What’s Happening?
Creating Accounts
Conclusion

Why Run an Ethereum Node?

learning purposes
personal and network benefits

Installing Geth

Geth is an open-source client written in Go
- there are plenty of clients to choose from but I’ve been trying to learn Go
start a node in a docker container
- connecting to the Görli test network to start
- mount volume as client’s data directory to ensure downloaded data is preserved between restarts and/or container lifecycles
  - mkdir /Users/ldong/Projects/Learning_Labs/blockchain/geth/goerli

docker run --name geth -v /Users/ldong/Projects/Learning_Labs/blockchain/geth/goerli:/root/.ethereum/geth/goerli \
  -p 8545:8545 -p 30303:30303 -dit \
  ethereum/client-go:latest --goerli

here are the ports that are automatically exposed:
- 8545 TCP, used by the HTTP based JSON RPC API
- 8546 TCP, used by the WebSocket based JSON RPC API
- 8547 TCP, used by the GraphQL API
- 30303 TCP and UDP, used by the P2P protocol running the network

What’s Happening?

docker logs geth -f

INFO [11-10|19:39:50.265] Starting Geth on Görli testnet...
INFO [11-10|19:39:50.274] Maximum peer count                       ETH=50 LES=0 total=50
INFO [11-10|19:39:50.274] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
WARN [11-10|19:39:50.276] Sanitizing cache to Go's GC limits       provided=1024 updated=662
INFO [11-10|19:39:50.276] Set global gas cap                       cap=50,000,000
INFO [11-10|19:39:50.277] Allocated trie memory caches             clean=99.00MiB dirty=165.00MiB
INFO [11-10|19:39:50.277] Allocated cache and file handles         database=/root/.ethereum/goerli/geth/chaindata cache=329.00MiB handles=524,288
INFO [11-10|19:39:50.303] Opened ancient database                  database=/root/.ethereum/goerli/geth/chaindata/ancient readonly=false
INFO [11-10|19:39:50.303] Writing custom genesis block
INFO [11-10|19:39:50.311] Persisted trie from memory database      nodes=361 size=51.17KiB time=1.4678ms gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [11-10|19:39:50.312] Initialised chain configuration          config="{ChainID: 5 Homestead: 0 DAO: <nil> DAOSupport: true EIP150: 0 EIP155: 0 EIP158: 0 Byzantium: 0 Constantinople: 0 Petersburg: 0 Istanbul: 1561651, Muir Glacier: <nil>, Berlin: 4460644, London: 5062605, Arrow Glacier: <nil>, Engine: clique}"
INFO [11-10|19:39:50.314] Initialising Ethereum protocol           network=5 dbversion=<nil>

connecting to geth can be done via RPC or IPC
- RPC = remote node connection over HTTP
- IPC = direct node connection using JavaScript console (can do more with IPC)
  - it stands for Interprocess Communication and is a mechanism for establishing a connection between processes which allows data flow between them
let’s hop into the container with docker exec -it geth sh
connect via IPC
- geth attach /root/.ethereum/goerli/geth.ipc

Welcome to the Geth JavaScript console!

instance: Geth/v1.10.13-unstable-0efed7f5-20211109/linux-amd64/go1.17.3
at block: 0 (Wed Jan 30 2019 13:26:31 GMT+0000 (UTC))
 datadir: /root/.ethereum/goerli
 modules: admin:1.0 clique:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

gather peer information from within the JavaScript console such as number of peers and detailed info of peers, check block number

> net.peerCount
1
> admin.peers
[{
    caps: ["eth/65", "eth/66", "les/2", "les/3", "les/4", "snap/1"],
    enode: "enode://63037fb2d7072e30fdcafeb386e6fc9edab80b5b4b933a1a799d28343cde857de2b3ca1c33266f50740ce1cecdd99aefe49c469cc1186a349eb8cd4f19b4dc33@65.19.136.133:30303",
    enr: "enr:-KO4QB77nof221Oksl_L-S-yiWVIjTJx1Tx4o-vkA8YqiJgpBTQi4DwYpUJQoZzxzJQTt9f06_ZSwF5ugPmOo-odV2QFg2V0aMfGhLjGKZ2AgmlkgnY0gmlwhEETiIWDbGVzwQGJc2VjcDI1NmsxoQNjA3-y1wcuMP3K_rOG5vye2rgLW0uTOhp5nSg0PN6FfYRzbmFwwIN0Y3CCdl-DdWRwgnZf",
    id: "551ff030a46f72e1bb26d3bbc2f0d3cc1b6e01a6b588e651095a25150b360fd8",
    name: "Geth/v1.10.8-stable-26675454/linux-amd64/go1.16.4",
    network: {
      inbound: false,
      localAddress: "172.17.0.2:58772",
      remoteAddress: "65.19.136.133:30303",
      static: false,
      trusted: false
    },
    protocols: {
      eth: {
        difficulty: 8536335,
        head: "0xcfe8c31251f3dc585e78fdf4c1381dcfb31b0c32727ccb67f0a63db3e25f90a6",
        version: 66
      },
      snap: {
        version: 1
      }
    }
}]
> eth.blockNumber
0

thoughts
- I should probably reference the web3.js docs
- why am I only connected to one peer? is that normal?
- why is the blockNumber 0?
  - found the answer from the lead geth developer himself
  - (the reason has to do with fast syncing)

Creating Accounts

geth --goerli account new

Your new key was generated

Public address of the key:   0xC3e10Ac93531E1C8c541AC117F410d00a855996e
Path of the secret key file: /root/.ethereum/goerli/keystore/UTC--2021-11-10T23-33-36.940215200Z--c3e10ac93531e1c8c541ac117f410d00a855996e

in console: eth.accounts

["0xc3e10ac93531e1c8c541ac117f410d00a855996e"]

Conclusion

I played around and struggled with this for a decent amount of time. It is SUPER easy to run a node but it’s not so easy understanding what’s going on in the backend. Some of the things I attempted to do:

connect to metamask extension via RPC
migrate my last deployed smart contract to Görli test network
import and export accounts
run dev mode network
set up a private network with genesis json file
- I learned that ganache is a lot more user friendly than geth

I haven’t even begun to try and do some mining. That’s for another day. For now, I’ll continue poking around in the Görli test network. I have to make a tweet or post something on Facebook to get Ether from the Goerli Authenticated Faucet so I think right now is a good break point. I have my node up and running inside a Docker container and I now understand how to run geth and javascript console commands!

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