Steps to geth private network with allocated accounts

genesis.json

{
  "config": {
    "chainId": <your network id>,
    "homesteadBlock": 1,
    "eip150Block": 2,
    "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "eip155Block": 3,
    "eip158Block": 3,
    "byzantiumBlock": 4,
    "ethash": {}
  },
  "nonce": "0x0",
  "timestamp": "0x5a04bae4",
  "extraData": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "gasLimit": "0x47b760",
  "difficulty": "0x400",
  "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "<your address>",
  "alloc": {
    "<your address>": {"balance":"9900000000000000000000000000000000000"},
    "<your address 2>": {"balance":"100xlambos"}
  },
  "number": "0x0",
  "gasUsed": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

geth_private_network_allocated_ether

#1 Create the account(s) and set password, BEFORE initializing the chain
geth --datadir ./path/to/chaindata/folder account new

#2 Write down the address and change it in genesis.json

#3 Initialize the chain
geth --datadir ./path/to/chaindata init ./path/to/genesis.json

# You should see
#INFO [11-09|23:56:37] Allocated cache and file handles         database=/path/to/chaindata/geth/chaindata cache=16 handles=16
#INFO [11-09|23:56:37] Writing custom genesis block 
#INFO [11-09|23:56:37] Successfully wrote genesis state         database=chaindata                                                                hash=4cba80…0e6caa
#INFO [11-09|23:56:37] Allocated cache and file handles         database=/path/to/chaindata/geth/lightchaindata cache=16 handles=16
#INFO [11-09|23:56:37] Writing custom genesis block 
#INFO [11-09|23:56:37] Successfully wrote genesis state         database=lightchaindata  

#4 Start geth with rpc enabled so truffle / geth attach can connect
geth --datadir=./path/to/chaindata --rpc --rpccorsdomain "*" --identity "coverage" --port=<port number> --rpcport=<port>

#5 You could connect from other terminal
geth attach ./chaindata/geth.ipc 

#6 Check the account(s) have the moneys
balance = web3.fromWei(eth.getBalance(eth.accounts[0]), "ether");

#6 mine to get to byzantium fork block defined in genesis.json
miner.start();

#7 ????

#8 PROFIT!!!

#9 Stop the miner eventually
miner.stop();