1. 介绍

本文我们演示如何使用以太坊客户端搭建以太坊的私有链。
环境:Ubuntu 16.04

2. 步骤

2.1 安装客户端

从以下地址下载以太坊Linux包

https://github.com/ethereum/mist/releases

安装

sudo apt-get -f install libappindicator1 libindicator7
sudo dpkg -i Mist-linux64-0-9-0.deb

设置geth执行路径,编辑.bashrc

export PATH=$PATH:~/.config/Mist/binaries/Geth/unpacked

2.2 建立目录和genesis.json

创建目录

sudo mkdir /opt/mychains

cd /opt/mychains,编辑genesis.json

{
"nonce": "0x0000000000000042",     
"timestamp": "0x00",
"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"extraData": "0x00",     
"gasLimit": "0x8000000",     
"difficulty": "0x400",
"mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"coinbase": "0x3333333333333333333333333333333333333333",     
"alloc": {
 },
"config": {
    "chainId": 15,
    "homesteadBlock": 0,
    "eip155Block": 0,
    "eip158Block": 0
    }
}

Mixhash
一个256位的哈希值,和nonce配合,一起用来证明在区块链上已经做了足够的计算量(工作证明)。这个nonce 和 mixhash 的组成,必须满足一个在黄皮书中所描述的数学上的条件,黄皮书 4.3.4。
Nonce
一个64位的哈希值,和mixhash配合,一起用来证明在区块链上已经做了足够的计算量(工作证明)
Difficulty
定义挖矿的目标,可以用上一个区块的难度值和时间戳计算出来,值越高,矿工越难挖到区块
Alloc 预先填入一些钱包和余额
Coinbase
160位的钱包地址。在创世区块中可以被定义成任何的地址,因为当每挖到一个区块的时候,这个值会变成矿工的etherbase地址
Timestamp 一个unix的time()函数的输出值,时间戳
extraData 32字节长度,可以为私有链留下一些信息,如你的姓名等,用以证明这个私有链是你创建的
gasLimit 当前链,一个区块所能消耗的gas上限

2.3 初始化创世块

geth --identity "mydev1" --rpc --rpccorsdomain "*" --datadir "./mydev1" --rpcapi "db,eth,net,web3" --networkid 100 init "./genesis.json"

WARN [09-02|21:15:15] No etherbase set and no accounts found as default 
INFO [09-02|21:15:15] Allocated cache and file handles database=/opt/mychains/mydev1/geth/chaindata cache=16 handles=16
INFO [09-02|21:15:15] Writing custom genesis block 
INFO [09-02|21:15:15] Successfully wrote genesis state database=chaindata  hash=6650a0…b5c158
INFO [09-02|21:15:15] Allocated cache and file handles database=/opt/mychains/mydev1/geth/lightchaindata cache=16 handles=16
INFO [09-02|21:15:15] Writing custom genesis block 
INFO [09-02|21:15:15] Successfully wrote genesis state atabase=lightchaindata hash=6650a0…b5c158

2.4 启动私有链

geth --datadir "./mydev1" --identity "mydev1" --rpccorsdomain "*" --networkid 100 console

WARN [09-02|21:21:00] No etherbase set and no accounts found as default 
INFO [09-02|21:21:00] Starting peer-to-peer node               instance=Geth/mydev1/v1.6.6-stable-10a45cb5/linux-amd64/go1.8.3
INFO [09-02|21:21:00] Allocated cache and file handles         database=/opt/mychains/mydev1/geth/chaindata cache=128 handles=1024
WARN [09-02|21:21:00] Upgrading chain database to use sequential keys 
INFO [09-02|21:21:00] Initialised chain configuration          config="{ChainID: 15 Homestead: 0 DAO: <nil> DAOSupport: false EIP150: <nil> EIP155: 0 EIP158: 0 Metropolis: <nil> Engine: unknown}"
INFO [09-02|21:21:00] Disk storage enabled for ethash caches   dir=/opt/mychains/mydev1/geth/ethash count=3
INFO [09-02|21:21:00] Disk storage enabled for ethash DAGs     dir=/home/alex/.ethash               count=2
WARN [09-02|21:21:00] Upgrading db log bloom bins 
INFO [09-02|21:21:00] Bloom-bin upgrade completed              elapsed=248.19µs
INFO [09-02|21:21:00] Initialising Ethereum protocol           versions="[63 62]" network=100
INFO [09-02|21:21:00] Loaded most recent local header          number=0 hash=6650a0…b5c158 td=1024
INFO [09-02|21:21:00] Loaded most recent local full block      number=0 hash=6650a0…b5c158 td=1024
INFO [09-02|21:21:00] Loaded most recent local fast block      number=0 hash=6650a0…b5c158 td=1024
INFO [09-02|21:21:00] Starting P2P networking 
INFO [09-02|21:21:00] Database conversion successful 
INFO [09-02|21:21:00] UDP listener up                          self=enode://4203871e783238ac002006ded5de0627d3bd05e76403833ba4c2b3ecec0e98cec[email protected]192.168.1.5:30303
INFO [09-02|21:21:00] RLPx listener up                         self=enode://4203871e783238ac002006ded5de0627d3bd05e76403833ba4c2b3ecec0e98cec[email protected]192.168.1.5:30303
INFO [09-02|21:21:00] IPC endpoint opened: /opt/mychains/mydev1/geth.ipc 
Welcome to the Geth JavaScript console!

instance: Geth/mydev1/v1.6.6-stable-10a45cb5/linux-amd64/go1.8.3
 modules: admin: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

INFO [09-02|21:21:01] Mapped network port                      proto=udp extport=30303 intport=30303 interface=NAT-PMP(192.168.199.1)
INFO [09-02|21:21:01] Mapped network port                      proto=tcp extport=30303 intport=30303 interface=NAT-PMP(192.168.199.1)

2.5 创建账号并启动挖矿

创建账号personal.newAccount(“123456”)

"0x852ffa22f80d5ce869b94bcf60fbe60bb867415a"
INFO [09-02|21:31:48] New wallet appeared url=keystore:///opt/mychains/mydev1… status=Locked

启动挖矿miner.start()

INFO [09-02|21:33:09] Updated mining threads  threads=0
INFO [09-02|21:33:09] Transaction pool price threshold updated price=18000000000    null
INFO [09-02|21:33:09] Starting mining operation 
INFO [09-02|21:33:09] Commit new mining work number=1 txs=0 uncles=0 elapsed=131.912µs
INFO [09-02|21:33:25] Generating DAG in progress  epoch=1 percentage=0 elapsed=13.305s
INFO [09-02|21:33:37] Generating DAG in progress  epoch=1 percentage=1 elapsed=24.781s
INFO [09-02|21:33:48] Generating DAG in progress  epoch=1 percentage=2 elapsed=36.059s
INFO [09-02|21:33:59] Generating DAG in progress  epoch=1 percentage=3 elapsed=47.375s
INFO [09-02|21:34:10] Generating DAG in progress  epoch=1 percentage=4 elapsed=58.127s
INFO [09-02|21:34:15] Successfully sealed new block  number=1 hash=1a9b10…5d488d
INFO [09-02|21:34:15] 🔨 mined potential block  number=1 hash=1a9b10…5d488d
INFO [09-02|21:34:15] Commit new mining work  number=2 txs=0 uncles=0 elapsed=5.490ms
INFO [09-02|21:34:17] Successfully sealed new block  number=2 hash=8fc2dc…501949
INFO [09-02|21:34:17] 🔨 mined potential block  number=2 hash=8fc2dc…501949
INFO [09-02|21:34:17] Commit new mining work  number=3 txs=0 uncles=0 elapsed=176.082µs
INFO [09-02|21:34:21] Generating DAG in progress  epoch=1 percentage=5 elapsed=1m9.380s

2.6 检验挖矿是否成功

查看主账户的以太币数量

acc0=eth.accounts[0]
eth.getBalance(acc0)

结果只要不为0,那就说明挖矿成功!

40000000000000000000