ConsenSys/local_ethereum_network

Name: local_ethereum_network

Owner: ConsenSys

Description: Creating a Local Ethereum Blockchain

Forked from: krisrandall/codecave_ethereum_blockchain

Created: 2018-01-05 05:11:23.0

Updated: 2018-01-10 19:29:54.0

Pushed: 2018-01-12 16:51:56.0

Homepage: null

Size: 7

Language: null

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README

Local Ethereum Network

See also : https://github.com/ethereum/go-ethereum/wiki/Private-network

Setting up your Ethereum Node(s)

1. Prereq : Install Geth

For windows : https://ethereum.github.io/go-ethereum/downloads/

For a mac :

ew update
ew upgrade
ew tap ethereum/ethereum
ew install ethereum

For linux (Ubuntu)

 apt-get install software-properties-common
 add-apt-repository -y ppa:ethereum/ethereum
 apt-get update
 apt-get install ethereum

2. Prereq : create /projects

Create a /projects symbolic link
(Note: This step is simply so “/projects” can be used in all other commands, instead you could use full paths, or set an env var)

dir <my projects folder>
do ln -s <my projects folder> /projects

3. Create local_ethereum_blockchain folder

dir /projects/local_ethereum_blockchain

4. Create the genesis block config

Create this file : /projects/local_ethereum_blockchain/genesis.json

With the following contents :

 "config": {
   "chainId": 1000,
   "homesteadBlock": 0,
   "eip155Block": 0,
   "eip158Block": 0
            },
 "nonce": "0x0000000000000061",
 "timestamp": "0x0",
 "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000", 
 "gasLimit": "0x8000000",   
 "difficulty": "0x100",    
 "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
 "coinbase": "0x3333333333333333333333333333333333333333",
 "alloc": {}

(info about the genesis file)

5. Initialise an Ethereum node

th --datadir /projects/local_ethereum_blockchain/node1 init /projects/local_ethereum_blockchain/genesis.json

6. Start that Ethereum node

th --datadir /projects/local_ethereum_blockchain/node1 --networkid 1000 console

7. Initialise another Ethereum node

th --datadir /projects/local_ethereum_blockchain/node-2 init /projects/local_ethereum_blockchain/genesis.json

8. Start the 2nd Ethereum node

th --datadir /projects/local_ethereum_blockchain/node-2 --port 30304 --nodiscover --networkid 1000 console

9. Connect one node to the other

In one geth console :

min.nodeInfo.enode

In the other console :

min.addPeer( <the enode value from the first console> )

Useful geth commands

Node info

min.nodeInfo

Peers

Show peers

min.peers

How many peers ?

min.peers.length

Create an account

You need an account to do be able to do things like mining

rsonal.newAccount()

And make sure your remember/save the password!

Unlock account

Neccessary before some actions

rsonal.unlockAccount( eth.accounts[0] )

Start mining

ner.start(1)

The first block may take a while to mine, allow a few minutes

Stop mining

ner.stop() 

Current block number

h.blockNumber

Details of current block

h.getBlock( eth.blockNumber ) 

Which node minded the last block

h.getBlock(eth.blockNumber).miner

Account balance, in ether

b3.fromWei(eth.getBalance(eth.accounts[0]))

Transfer ether between accounts

First get the account numbers by doing

> eth.accounts

Then unlock the account you are sending from

> personal.unlockAccount( <from account> )

eg.

> personal.unlockAccount(eth.accounts[0])

Finally transfer 1 ether

h.sendTransaction({from: "<from account>", to: "<to account>", value: web3.toWei(1, "ether")})

Exit

it

(This will also stop the node from running if it was started using $ geth console (as opposed to $ geth attach))

Connect to other nodes on your network

1. Get the IP of the node : $ ifconfig|grep netmask|awk '{print $2}'

2. Get the enode of the node : > admin.nodeInfo.enode

3. REPLACE [::] in the enode string with the [<ip address>]

4. On your console > admin.addPeer(< the enode string with the ip address in it>)