教程：在以太坊上创建私链private chain

ntc30461ifk

有两种以太坊客户端可以选择：

• Eth - C++ implementationGeth - Go implementation
  

本教程是基于Geth. 安装教程可以到 frontier gitbook.

创建创世块

创世块的最大特点是第一个块，所以没有与之前的块产生联系。在比特币系统里，这个创世块是被写入源码，但对于以太坊而言，创世块可以是任何你喜欢的东西。你也可以把这个当成是系统的一个漏洞。但是共识算法确保其它人除非纳入你的创世块，否则是不会有效的。（以后再详细说）

Great, so how do we make one of these genesis blocks? Well its fairly simple the following JSON is all you really need:

• {
  
• "nonce": "0xdeadbeefdeadbeef",
  
• "timestamp": "0x0",
  
• "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  
• "extraData": "0x0",
  
• "gasLimit": "0x8000000",
  
• "difficulty": "0x400",
  
• "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  
• "coinbase": "0x3333333333333333333333333333333333333333",
  
• "alloc": {
  
• }}
  

复制代码

Kudos to obscuren

在本地硬盘上存储这个 JSON，然后运行以下命令：

$ geth --genesis  --datadir  --networkid 123 --nodiscover --maxpeers 0 console

复制代码
这个命令做了如下几个事情：

• 调用创世块JSON进区块链里。
  
• 使用 datadir 来存储相关数据，并且维护新创建的区块及其它数据 (declared to prevent you clobbering your main net data, wouldn’t want to overwrite all those blocks you spent time downloading!)
  
• 使用网络ID ‘1’ 确保我们无法与主网的节点进行通讯。 ? “connections between nodes are valid only if peers have identical protocol version and network id”
  
• 禁用同伴发现。
  
• 把maxpeers 设置为 0禁用网络。以控制台模式启动 geth客户端，这样你就可以与你的新区块链接/节点进行通讯。
  

接下来就可以根据 testing contracts and transactions 的指示创建区块和帐户了。我这里的区别是禁用了PRC, 表现证明的公认搜集过程( the proof performance metric gathering processes) ，extra verbosity and vmdebu，目的是简单化。

在上述创世块里，我把难度设置的很低，这样的话我的本地电脑就能够挖矿，很容易获得以太币。

种子帐户 accounts with allocation

接下来，就有必要创建新的种子帐户了（以便存储挖矿所得的以太币）。 很简单，先创建一个新区块链和新帐户:

• $ geth --genesis  --datadir /.../dapps/test-genesis/.ethereum --networkid 123 --nodiscover --maxpeers 0 console
  
• I0829 13:30:07.340636 3987 database.go:74] Alloted 16MB cache to /.../dapps/test-genesis/.ethereum/blockchain
  
• I0829 13:30:07.342982 3987 database.go:74] Alloted 16MB cache to /.../dapps/test-genesis/.ethereum/state
  
• I0829 13:30:07.345055 3987 database.go:74] Alloted 16MB cache to /.../dapps/test-genesis/.ethereum/extra
  
• I0829 13:30:07.347363 3987 backend.go:291] Protocol Versions: [61 60], Network Id: 12345
  
• I0829 13:30:07.347738 3987 backend.go:303] Successfully wrote genesis block. New genesis hash = 82b6159155c00fb0b420046012a02257a176ad5dcfce4be4a15da39c166518e2
  
• I0829 13:30:07.347771 3987 backend.go:328] Blockchain DB Version: 3
  
• I0829 13:30:07.347866 3987 chain_manager.go:241] Last block (#0) 82b6159155c00fb0b420046012a02257a176ad5dcfce4be4a15da39c166518e2 TD=1024
  
• I0829 13:30:07.353373 3987 cmd.go:124] Starting Geth/v1.0.1/darwin/go1.4.2
  
• I0829 13:30:07.353470 3987 server.go:312] Starting Server
  
• I0829 13:30:07.353610 3987 backend.go:564] Server started
  
• I0829 13:30:07.353548 3987 server.go:549] Listening on [::]:30310
  
• I0829 13:30:07.353961 3987 ipc_unix.go:78] IPC service started (/.../dapps/test-genesis/.ethereum/geth.ipc)
  
• instance: Geth/v1.0.1/darwin/go1.4.2
  
• datadir: /.../dapps/test-genesis/.ethereum
  
• coinbase: 0x1fb891f92eb557f4d688463d0d7c560552263b5a
  
• at block: 0 (1970-01-01 01:00:00)
  
• modules: admin:1.0 db:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 shh:1.0 txpool:1.0 web3:1.0
  
• > personal.newAccount("mypassword"); '0x1fb891f92eb557f4d688463d0d7c560552263b5a'
  

复制代码

上面代码的最后一行创建了一个新的帐户，其地址是 0x1fb891f92eb557f4d688463d0d7c560552263b5a.

创建帐户后，用  退出geth客户端，然后在你的datadir文件夹里，保留 keystore/ 这个文件夹，其余的全部删掉。

• $ cd$ rm -rf `ls | grep -v keystore`
  

复制代码
接下来就是见证奇迹的时候，刷新你的创世块JSON，把下面的代码加入 alloc 键:

• "alloc": {
  
• "": {
  
• "balance": "10000000000000000000"
  
• }}
  

复制代码
现在重新运行geth命令行，使用刚才刷新过的 genesis json文件，还有相同的datadir，然后你会发现帐户余额里，多了10个以太币出来。

• $ geth --genesis  --datadir /.../dapps/test-genesis/.ethereum --networkid 123 --nodiscover --maxpeers 0 console
  
• I0829 13:30:07.340636 3987 database.go:74] Alloted 16MB cache to /.../dapps/test-genesis/.ethereum/blockchain
  
• I0829 13:30:07.342982 3987 database.go:74] Alloted 16MB cache to /.../dapps/test-genesis/.ethereum/state
  
• I0829 13:30:07.345055 3987 database.go:74] Alloted 16MB cache to /.../dapps/test-genesis/.ethereum/extra
  
• I0829 13:30:07.347363 3987 backend.go:291] Protocol Versions: [61 60], Network Id: 12345
  
• I0829 13:30:07.347738 3987 backend.go:303] Successfully wrote genesis block. New genesis hash = 82b6159155c00fb0b420046012a02257a176ad5dcfce4be4a15da39c166518e2
  
• I0829 13:30:07.347771 3987 backend.go:328] Blockchain DB Version: 3
  
• I0829 13:30:07.347866 3987 chain_manager.go:241] Last block (#0) 82b6159155c00fb0b420046012a02257a176ad5dcfce4be4a15da39c166518e2 TD=1024
  
• I0829 13:30:07.353373 3987 cmd.go:124] Starting Geth/v1.0.1/darwin/go1.4.2
  
• I0829 13:30:07.353470 3987 server.go:312] Starting Server
  
• I0829 13:30:07.353610 3987 backend.go:564] Server started
  
• I0829 13:30:07.353548 3987 server.go:549] Listening on [::]:30310
  
• I0829 13:30:07.353961 3987 ipc_unix.go:78] IPC service started (/.../dapps/test-genesis/.ethereum/geth.ipc)
  
• instance: Geth/v1.0.1/darwin/go1.4.2
  
• datadir: /.../dapps/test-genesis/.ethereum
  
• coinbase: 0x1fb891f92eb557f4d688463d0d7c560552263b5a
  
• at block: 0 (1970-01-01 01:00:00)
  
• modules: admin:1.0 db:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 shh:1.0 txpool:1.0 web3:1.0
  
• > primary = eth.accounts[0];
  
• '0x1fb891f92eb557f4d688463d0d7c560552263b5a'
  
• > balance = web3.fromWei(eth.getBalance(primary), "ether"); '10'
  

复制代码