geth --datadir ./ init customgenesis.json

Fatal: Failed to read genesis file: open customgenesis.json: no such file or directory

  • Do you have the customgenesis.json in same directory as your console directory? if not, provide proper path to it. – sp4c3 Jan 24 '19 at 6:19
  • how to find customgenesis.json in ubuntu 16.04 – bhemeswararao ankireddy Jan 24 '19 at 6:43

In order to start a network you need to have a genesis file. This genesis file will be having details about the accounts in the network, difficulty of the block, network id , chain id etc. Copy the below config and save it a file with ".json"

  "alloc": {
  "0xe2138366adc7bae0b41d205e7d0ba8fadadd8e33": {
  "balance": "99999999999999999"
"config": {
  "chainId": 15,
  "homesteadBlock": 0,
  "eip155Block": 0,
  "eip158Block": 0
"coinbase": "0xe2138366adc7bae0b41d205e7d0ba8fadadd8e33",
"difficulty": "0x20000",
"extraData": "","gasLimit":"0x2fefd8",

then, use the following command in the directory you have saved that file and then initialize a network with that genesis file

geth --datadir="." init fileName
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It looks like you don't have the file customgenesis.json.

You can create a custom genesis file using the wizard from the puppeth tool.

You can download it at https://geth.ethereum.org/downloads/ (Geth & Tools)

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