教程：在以太坊上创建私链private chain

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。在比特币体系里，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爱的东西。你也可以把这个当成是体系的一个漏洞。可是共识算法保证其它人除非归入你的创世块，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:

https://bicoin8.com/wp-content/uploads/2023/04/202304211cHpE0.jpg

"nonce": "0xdeadbeefdeadbeef",

"timestamp": "0x0",

"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",

"extraData": "0x0",

"gasLimit": "0x8000000",

"difficulty": "0x400",

"mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",

"coinbase": "0x3333333333333333333333333333333333333333",

"alloc": https://bicoin8.com/wp-content/uploads/2023/04/202304211cHpE0.jpg

}

}

Kudos to obscuren

在本地硬盘上存储这个 JSON，然后运行以下指令：

这个指令做了如下几个工作：

调用创世块JSON进区块链里。

运用 datadir 来存储相关数据，并且保护新创立的区块及其它数据 (declared to prevent you clobbering your main net data, wouldn’t want to overwrite all those blocks you spent time downloading!)

运用网络ID ‘1’ 保证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。

以控制台形式发动 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 的指示创立区块和帐户了。我这儿的区别是禁用了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可以挖矿，很容易获得以太币。

接下来，就有必要创立新的种子帐户了（以便存储挖矿所得的以太币）。 很简单，先创立一个新区块链和新帐户:

$ geth --genesis <genesis json file path> --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'

上面代码的最终一行创立了一个新的帐户，其地址是 0x1fb891f92eb557f4d688463d0d7c560552263b5a.

创立帐户后，用 <ctrl-c> 退出geth客户端，然后在你的datadir文件夹里，保留 keystore/ 这个文件夹，其他的全部删掉。

$ cd <your datadir>

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

接下来就是见证奇观的时分，改写你的创世块JSON，把下面的代码加入 alloc 键:

"alloc": https://bicoin8.com/wp-content/uploads/2023/04/202304211cHpE0.jpg

"<your account address e.g. 0x1fb891f92eb557f4d688463d0d7c560552263b5a>": https://bicoin8.com/wp-content/uploads/2023/04/202304211cHpE0.jpg

"balance": "10000000000000000000"

}

}

现在从头运行geth指令行，运用方才改写过的 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 <updated genesis json file path> --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'