How to Setup Constantinople Fork for Private Ethereum Chain

constantinoplego-ethereum

I am trying to add the constantinople fork to my private net with is running on geth. I have updated to latest geth, geth 1.8.23.

I have stopped my current geth node running and have chnged the genesis file by adding constantinople block as below in config file

"config": {
"chainId": 56312,
"homesteadBlock": 0,
"eip155Block": 0,
"eip158Block": 0, "constantinopleBlock": 16275, "byzantiumBlock": 0
}

However, when I try to init the geth with new config, O am getting below error

Fatal: Failed to write genesis block: mismatching Constantinople fork block in database (have <nil>, want 16275, rewindto 16274)

Could someone help me to add constantinople fork to my private net.

Best Answer

I tried this and worked (but I recommend to create a backup):

=> xxxxxx is the future block number you want to do hardfork your private ethereum chain.

1- Alter the .json file by adding "constantinopleBlock": xxxxxx, "petersburgBlock": xxxxxx. PetersburgBlock is the Constantinople fix due to a security hole of Constantinople.

2- Run the command: geth --datadir <your datadir> init <genesis>.json

3- Restart running your geth, and you should see something like follows:

INFO [07-10|13:46:36.647] Initialised chain configuration          
config="{ChainID: 23422 ..... Constantinople: <xxxxxx> Petersburg: <xxxxxx> }"

and the chain data remains but the admin.nodeinfo, node's enode is updated.

Related Solutions

[Ethereum] Fatal: failed to write genesis block: wrong genesis block in database

You cannot do a init again if you have already done a init on datadir. In order to achive what you want you need to first create simply create account .... once account is created use that for pre-funding, by putting it in the genesis file, now go for the init of datadir.

so steps are
1) Creation of account in datadir

geth --datadir <path_of_data_directory> account new ( I have used command line method for account creation, which does not require invocation of geth console)

2) use the account created as pre-funded account, add entry in genesis file.

3) Init of the datadirectory with the genesis file.

geth --datadir <path_of_data_directory> init <path_of_genesis_file>

I have used bare minimum parameters, it should also work fine with the parameter you are using. Main point to note you cannot re-initialize your data directory once it is initialized.

[Ethereum] How to generate the correct go-ethereum bootnode when creating a private blockchain

If you can't telnet then there is something wrong with your networking. Either your virtual network connection between hosts is the problem or there is a firewall blocking connections.

If you are just getting started then I'd keep things really simple first of all and:

Use standard geth nodes
Run your nodes on one virtual machine on different ports

e.g. initialise your geth nodes like this:

ethuser@host01:~$ mkdir test1
ethuser@host01:~$ cd test1
ethuser@host01:~/test1$ mkdir nodeA
ethuser@host01:~/test1$ mkdir nodeB
ethuser@host01:~/test1$ <use your favourite editor to create a genesis.json file in this directory>
ethuser@host01:~/test1$ geth --datadir nodeA init genesis.json
WARN [08-04|10:41:41] No etherbase set and no accounts found as default 
INFO [08-04|10:41:41] Allocated cache and file handles         database=/home/ethuser/test1/nodeA/geth/chaindata cache=16 handles=16
INFO [08-04|10:41:41] Writing custom genesis block 
INFO [08-04|10:41:41] Successfully wrote genesis state         database=chaindata                                hash=dd3f8d…707d0d
INFO [08-04|10:41:41] Allocated cache and file handles         database=/home/ethuser/test1/nodeA/geth/lightchaindata cache=16 handles=16
INFO [08-04|10:41:41] Writing custom genesis block 
INFO [08-04|10:41:41] Successfully wrote genesis state         database=lightchaindata                                hash=dd3f8d…707d0d
ethuser@host01:~/test1$ geth --datadir nodeB init genesis.json
WARN [08-04|10:41:52] No etherbase set and no accounts found as default 
INFO [08-04|10:41:52] Allocated cache and file handles         database=/home/ethuser/test1/nodeB/geth/chaindata cache=16 handles=16
INFO [08-04|10:41:52] Writing custom genesis block 
INFO [08-04|10:41:52] Successfully wrote genesis state         database=chaindata                                hash=dd3f8d…707d0d
INFO [08-04|10:41:52] Allocated cache and file handles         database=/home/ethuser/test1/nodeB/geth/lightchaindata cache=16 handles=16
INFO [08-04|10:41:52] Writing custom genesis block 
INFO [08-04|10:41:52] Successfully wrote genesis state         database=lightchaindata                                hash=dd3f8d…707d0d
ethuser@host01:~/test1$

Then launch your first geth node like this

ethuser@host01:~/test1$ geth --datadir nodeA --networkid 1234567 console
WARN [08-04|10:42:22] No etherbase set and no accounts found as default 
INFO [08-04|10:42:22] Starting peer-to-peer node               instance=Geth/v1.6.7-stable-ab5646c5/linux-amd64/go1.8.1
INFO [08-04|10:42:22] Allocated cache and file handles         database=/home/ethuser/test1/nodeA/geth/chaindata cache=128 handles=1024
WARN [08-04|10:42:22] Upgrading chain database to use sequential keys 
INFO [08-04|10:42:22] Initialised chain configuration          config="{ChainID: 1907 Homestead: 0 DAO: <nil> DAOSupport: false EIP150: <nil> EIP155: 0 EIP158: 0 Metropolis: <nil> Engine: unknown}"
INFO [08-04|10:42:22] Disk storage enabled for ethash caches   dir=/home/ethuser/test1/nodeA/geth/ethash count=3
INFO [08-04|10:42:22] Disk storage enabled for ethash DAGs     dir=/home/ethuser/.ethash                 count=2
WARN [08-04|10:42:22] Upgrading db log bloom bins 
INFO [08-04|10:42:22] Bloom-bin upgrade completed              elapsed=252.683µs
INFO [08-04|10:42:22] Initialising Ethereum protocol           versions="[63 62]" network=1234567
INFO [08-04|10:42:22] Database conversion successful 
INFO [08-04|10:42:22] Loaded most recent local header          number=0 hash=dd3f8d…707d0d td=40
INFO [08-04|10:42:22] Loaded most recent local full block      number=0 hash=dd3f8d…707d0d td=40
INFO [08-04|10:42:22] Loaded most recent local fast block      number=0 hash=dd3f8d…707d0d td=40
INFO [08-04|10:42:22] Starting P2P networking 
INFO [08-04|10:42:22] UDP listener up                          self=enode://9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817@[::]:30303
INFO [08-04|10:42:22] RLPx listener up                         self=enode://9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817@[::]:30303
INFO [08-04|10:42:22] IPC endpoint opened: /home/ethuser/test1/nodeA/geth.ipc 
Welcome to the Geth JavaScript console!

instance: Geth/v1.6.7-stable-ab5646c5/linux-amd64/go1.8.1
 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

>

And then start up your second node. In my case I needed to use ethuser@host01:~/test1$ geth --datadir nodeB --port 30304 --networkid 1234567 --bootnodes enode://9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817@127.0.0.1:30303

Wait a few moments to give the nodes a chance to connect and then double check in your console that admin.peers returns some more info, e.g.

> admin.peers
[{
    caps: ["eth/63"],
    id: "9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817",
    name: "Geth/v1.6.7-stable-ab5646c5/linux-amd64/go1.8.1",
    network: {
      localAddress: "127.0.0.1:41900",
      remoteAddress: "127.0.0.1:30303"
    },
    protocols: {
      eth: {
        difficulty: 40,
        head: "0xdd3f8d61f38ebc195a6c9b0e5888e7e035f31ecd92e4427fb01176b984707d0d",
        version: 63
      }
    }
}]
>

I've left out creating accounts etc as you don't specifically ask it but if you're interested here are some more of my own newbie experiences: https://alanbuxton.wordpress.com/2017/07/19/first-steps-with-ethereum-private-networks-and-smart-contracts-on-ubuntu-16-04/

Best Answer

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