Instalación de una red con un solo nodo

Es posible instalar una red con un solo nodo, a los efectos de testeo o desarrollo.

Se asume que ya está instalado geth, pero por ejemplo en Ubuntu se puede instalar con:

sudo add-apt-repository -y ppa:ethereum/ethereum
sudo apt-get update
sudo apt-get install ethereum

$ geth version
Geth
Version: 1.8.14-stable
Git Commit: 316fc7ecfc10d06603f1358c1f4c1020ec36dd2a
Architecture: amd64
Protocol Versions: [63 62]
Network Id: 1
Go Version: go1.10.1
Operating System: linux
GOPATH=
GOROOT=/usr/lib/go-1.10

Creación de directorios

A modo de ejemplo, crearemos un directorio devnet, dentro del cual existirá un subdirectorio network, que albergará un directorio por nodo (en este caso uno solo, llamado node).

$ mkdir -p devnet/network/node

Creación de cuentas

Debe crearse al menos una cuenta.

$ cd devnet
devnet$ geth --datadir network/node account new
INFO [10-11|11:36:05.231] Maximum peer count                       ETH=25 LES=0 total=25
Your new account is locked with a password. Please give a password. Do not forget this password.
Passphrase: 
Repeat passphrase: 
Address: {10c69b29d6f1bedc6fb97758f74a9f64eb2e7694}

En este caso la dirección de la cuenta es 0x10c69b29d6f1bedc6fb97758f74a9f64eb2e7694. La dirección también puede obtenerse de la última parte del nombre del archivo correspondiente en el directorio node/keystore/

~/devnet$ ls network/node/keystore/
UTC--2018-10-11T14-36-07.790871325Z--10c69b29d6f1bedc6fb97758f74a9f64eb2e7694

La passphrase solicitada se puede dejar vacía.

En los ejemplos de los pasos siguientes, debe reemplazarse la dirección 0x10c69b29d6f1bedc6fb97758f74a9f64eb2e7694 por la que se haya generado en el nodo a crear.

Creación del bloque génesis e inicialización de la red

Usaremos el programa puppeth, parte de geth:

devnet$ puppeth
+-----------------------------------------------------------+
| Welcome to puppeth, your Ethereum private network manager |
|                                                           |
| This tool lets you create a new Ethereum network down to  |
| the genesis block, bootnodes, miners and ethstats servers |
| without the hassle that it would normally entail.         |
|                                                           |
| Puppeth uses SSH to dial in to remote servers, and builds |
| its network components out of Docker containers using the |
| docker-compose toolset.                                   |
+-----------------------------------------------------------+

Please specify a network name to administer (no spaces or hyphens, please)
> devnet

Sweet, you can set this via --network=devnet next time!

INFO [10-11|11:40:40.128] Administering Ethereum network           name=devnet
WARN [10-11|11:40:40.129] No previous configurations found         path=/home/miguel/.puppeth/devnet

What would you like to do? (default = stats)
 1. Show network stats
 2. Configure new genesis
 3. Track new remote server
 4. Deploy network components
> 2

Which consensus engine to use? (default = clique)
 1. Ethash - proof-of-work
 2. Clique - proof-of-authority
> 2

How many seconds should blocks take? (default = 15)
> 

Which accounts are allowed to seal? (mandatory at least one)
> 0x10c69b29d6f1bedc6fb97758f74a9f64eb2e7694
> 0x

Which accounts should be pre-funded? (advisable at least one)
> 0x10c69b29d6f1bedc6fb97758f74a9f64eb2e7694
> 0x

Specify your chain/network ID if you want an explicit one (default = random)
> 12345
INFO [10-11|11:41:26.635] Configured new genesis block 

What would you like to do? (default = stats)
 1. Show network stats
 2. Manage existing genesis
 3. Track new remote server
 4. Deploy network components
> 2

 1. Modify existing fork rules
 2. Export genesis configuration
 3. Remove genesis configuration
> 2

Which file to save the genesis into? (default = devnet.json)
> genesis.json
INFO [10-11|11:41:41.689] Exported existing genesis block 

What would you like to do? (default = stats)
 1. Show network stats
 2. Manage existing genesis
 3. Track new remote server
 4. Deploy network components
> ^C

Finalizado este paso, el archivo genesis.json (si se eligió ese nombre), tiene la información necesaria para inicializar la red:

devnet$ geth --datadir network/node init genesis.json

Lanzar el nodo

devnet$ geth --datadir network/node/ --syncmode 'full' --port 30303 --rpc --rpcaddr 'localhost' --rpcport 8545 --rpcapi 'personal,db,eth,net,web3,txpool,miner' --networkid 12345 --gasprice '1' --unlock '0x10c69b29d6f1bedc6fb97758f74a9f64eb2e7694' --password /dev/null --mine

Conexión al nodo

Mediante IPC

$ geth attach network/node/geth.ipc 
Welcome to the Geth JavaScript console!

instance: Geth/v1.8.14-stable-316fc7ec/linux-amd64/go1.10.1
coinbase: 0xdf11900897ac4a842c1691dfd466b84adc7aa3d0
at block: 441 (Thu, 11 Oct 2018 12:06:52 -03)
 datadir: /home/miguel/devnet/network/node
 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

>

Mediante RPC

devnet$ geth attach http://localhost:8545
Welcome to the Geth JavaScript console!

instance: Geth/v1.8.14-stable-316fc7ec/linux-amd64/go1.10.1
coinbase: 0xdf11900897ac4a842c1691dfd466b84adc7aa3d0
at block: 448 (Thu, 11 Oct 2018 12:08:37 -03)
 modules: eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

>

Red_con_un_solo_nodo