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Setup Childchain in Private Testnet

Intro

If you successfully deployed rootchain with Setup Rootchain, let's run childchain at this time. The childchain is layer-2 blockchain of Tokamak which depends on rootchain. In this section, assumed that you had Setup Rootchain with in the same machine.

Setup Operator Node

Make sure that you did setup Rootchain.

Operator and challenger account to be used in root chain must have enough ether balance. Note that operator node will run successfully only when challenger account has at least 0.5 ETH.

1. Deploy rootchain contract

This section explains about deploy command and its parameters for deploying rootChain contract.

deploy command has 4 input parameters, <name of genesis file>, <CHAINID>, <PRE-ASSET>, <EPOCH>.

  • CHAINID : Chain id set by opertaor.
  • PRE-ASSET : Flag to allocate PETH to accounts in child chain at genesis or not.
  • EPOCH : Length of epoch. If EPOCH is 2, childchain will submit epoch every 2 blocks.

Tokamak Plasma's childchain provides Stamina, a fee payment method for childchain. For more details refer to Stamina.

You can change stamina parameters by adding flags as follows. If not using stamina flag, set default parameters.

  • --stamina.operatoramount : Operator stamina amount at genesis block in ETH (default: 1)
  • --stamina.mindeposit : Minimum deposit amount in ETH (default: 0.5)
  • --stamina.recoverepochlength : The length of recovery epoch in block (default: 120960)
  • --stamina.withdrawaldelay : Withdrawal delay in block (default: 362880)

In the case of stamina.withdrawaldelay, a value of at least two times more than stamina.recoverepochlength should be used.

The stamina feature is provided as a pre-compiled contract in childchain. The stamina contract address is 0x000000000000000000000000000000000000dead in every tokamak plasma childchain.

You can check this for more details about the stamina contract.

Create deploy.operator1.sh by running following command.

plasma-evm$ cat > deploy.operator1.sh << "EOF"
#!/bin/bash
OPERATOR_KEY="86e60281da515184c825c3f46c7ec490b075af1e74607e2e9a66e3df0fa22122"
OPERATOR="0x5e3230019fed7ab462e3ac277e7709b9b2716b4f"

DATADIR=.pls.staking/operator1

ROOTCHAIN_IP=127.0.0.1

# Deploy contracts at rootchain
echo "Deploy rootchain contract and others"
make geth && build/bin/geth \
    --nousb \
    --datadir $DATADIR \
    --rootchain.url "ws://$ROOTCHAIN_IP:8546" \
    --unlock $OPERATOR \
    --password pwd.pass \
    --rootchain.sender $OPERATOR \
    --stamina.operatoramount 1 \
    --stamina.mindeposit 0.5 \
    --stamina.recoverepochlength 120960 \
    --stamina.withdrawaldelay 362880 \
    deploy "./genesis-operator1.json" 102 true 2

# you can checkout "$geth deploy --help" for more information
EOF

You can run deploy.operator1.sh script as following command.

plasma-evm$ bash deploy.operator1.sh

genesis-operator1.json gerenated from the script will be located in plasma-evm directory.

2. Initialize

You must initialize chain data before running operator node.

genesis-operator1.json is located in current path(i.e ~/plasma-evm/genesis-operator1.json).

Run following command to initialize chain data.

plasma-evm$ build/bin/geth --nousb init \
            --datadir .pls.staking/operator1 \
            --rootchain.url ws://localhost:8546 \
            genesis-operator1.json

3. Set manager contract

After 2. Initialize for childchain, The Operator should register an address of the rootchain contract to stake manager contract.

After setting up the operator plasma chain, operator must register a rootchain contract address to the stake manager contract.

Using setManagers sub-command of manage-staking, set the stake contract addresses to run operator's plasma chain.

plasma-evm $ build/bin/geth --nousb manage-staking setManagers manager.json  \
            --datadir ./.pls.staking/operator1
INFO [01-01|00:00:00.000] Maximum peer count                       ETH=50 LES=0 total=50
INFO [01-01|00:00:00.000] Set options for submitting a block       mingaspirce=1000000000 maxgasprice=100000000000 resubmit=0s
INFO [01-01|00:00:00.000] Allocated cache and file handles         database=/home/ubuntu/plasma-evm/.pls.staking/operator1/geth/stakingdata cache=16.00MiB handles=16
INFO [01-01|00:00:00.000] Set address                              name=TON addr=0x3A220f351252089D385b29beca14e27F204c296A
INFO [01-01|00:00:00.000] Set address                              name=WTON addr=0xdB7d6AB1f17c6b31909aE466702703dAEf9269Cf
INFO [01-01|00:00:00.000] Set address                              name=DepositManager addr=0x880EC53Af800b5Cd051531672EF4fc4De233bD5d
INFO [01-01|00:00:00.000] Set address                              name=RootChainRegistry addr=0x537e697c7AB75A26f9ECF0Ce810e3154dFcaaf44
INFO [01-01|00:00:00.000] Set address                              name=SeigManager       addr=0x3Dc2cd8F2E345951508427872d8ac9f635fBe0EC
INFO [01-01|00:00:00.000] Set address                              name=PowerTON          addr=0xBcDfc870Ea0C6463C6EBb2B2217a4b32B93BCFB7

Check if the information of stake contract address is included in the operator chaindata with getManagers sub-command of manage-staking.

plasma-evm $ build/bin/geth --nousb \
              manage-staking getManagers \
              --datadir ./.pls.staking/operator1
INFO [01-01|00:00:00.000] Maximum peer count                       ETH=50 LES=0 total=50
INFO [01-01|00:00:00.000] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [01-01|00:00:00.000] Set options for submitting a block       mingaspirce=1000000000 maxgasprice=100000000000 resubmit=0s
INFO [01-01|00:00:00.000] Allocated cache and file handles         database=/home/ubuntu/plasma-evm/.pls.staking/manager/geth/stakingdata cache=16.00MiB handles=16
{
  "TON": "0x3a220f351252089d385b29beca14e27f204c296a",
  "WTON": "0xdb7d6ab1f17c6b31909ae466702703daef9269cf",
  "DepositManager": "0x880ec53af800b5cd051531672ef4fc4de233bd5d",
  "RootChainRegistry": "0x537e697c7ab75a26f9ecf0ce810e3154dfcaaf44",
  "SeigManager": "0x3dc2cd8f2e345951508427872d8ac9f635fbe0ec",
  "PowerTON": "0x82567a6f6e3abe246f62350322a07af7f413cfe6"
}

4. Register rootchain contract

Register the rootchain address of operator plasma chain to the stake manager contract in order to receive seigniorage.

plasma-evm $ build/bin/geth --nousb manage-staking register \
            --datadir ./.pls.staking/operator1 \
            --rootchain.url ws://127.0.0.1:8546 \
            --unlock 0x5e3230019fed7ab462e3ac277e7709b9b2716b4f \
            --password pwd.pass \
            --rootchain.sender 0x5e3230019fed7ab462e3ac277e7709b9b2716b4f

If rootchain address is successfully registered, you will see the following message.

INFO [01-01|00:00:00.000] Maximum peer count                       ETH=50 LES=0 total=50
INFO [01-01|00:00:00.000] Operator account is unlocked             address=0x5E3230019fEd7aB462e3AC277E7709B9b2716b4F
INFO [01-01|00:00:00.000] Set options for submitting a block       mingaspirce=1000000000 maxgasprice=100000000000 resubmit=0s
INFO [01-01|00:00:00.000] Allocated cache and file handles         database=/home/ubuntu/plasma-evm/.pls.staking/operator1/geth/stakingdata cache=16.00MiB handles=16
INFO [01-01|00:00:00.000] Using manager contracts                  TON=0x3A220f351252089D385b29beca14e27F204c296A WTON=0xdB7d6AB1f17c6b31909aE466702703dAEf9269Cf DepositManager=0x880EC53Af800b5Cd051531672EF4fc4De233bD5d RootChainRegistry=0x537e697c7AB75A26f9ECF0Ce810e3154dFcaaf44 SeigManager=0x3Dc2cd8F2E345951508427872d8ac9f635fBe0EC
INFO [01-01|00:00:00.000] Registered SeigManager to RootChain      registry=0x537e697c7AB75A26f9ECF0Ce810e3154dFcaaf44 rootchain=0x17FB80e2E16b02faC936933424305d4F29F9d5D9 seigManager=0x3Dc2cd8F2E345951508427872d8ac9f635fBe0EC tx=b546d3…fe55ed
INFO [01-01|00:00:00.000] Registered RootChain to SeigManager      registry=0x537e697c7AB75A26f9ECF0Ce810e3154dFcaaf44 rootchain=0x17FB80e2E16b02faC936933424305d4F29F9d5D9 seigManager=0x3Dc2cd8F2E345951508427872d8ac9f635fBe0EC tx=6904c9…bc07a5

5. Run Operator node

Run operator node with following command.

plasma-evm$ build/bin/geth \
    --nousb \
    --datadir ./.pls.staking/operator1 \
    --syncmode='full' \
    --networkid 102 \
    --rootchain.url ws://127.0.0.1:8546 \
    --operator 0x5e3230019fed7ab462e3ac277e7709b9b2716b4f \
    --port 30306 \
    --nat extip:::1 \
    --maxpeers 50 \
    --unlock 0x5e3230019fed7ab462e3ac277e7709b9b2716b4f \
    --password pwd.pass \
    --nodekeyhex e854e2f029be6364f0f961bd7571fd4431f99355b51ab79d23c56506f5f1a7c3 \
    --mine \
    --miner.gastarget 7500000 \
    --miner.gaslimit 10000000

Setup User Node

This guide describes how to run user node without setting challenger account.

You can add challenger flag to run challneger node. Note that account balance of challenger must be more than 0.5ETH.

1. Initialize

Insert URL of RootChain on which RootChain Contract was deployed, as parameter of --rootchain.url flag.

Use the address of RootChain set in here as --rootchain.url.

plasma-evm$ build/bin/geth --nousb init \
            --datadir ./.pls.staking/usernode \
            --rootchain.url ws://localhost:8546 \
            genesis-operator1.json

Use same genesis-operator1.json file as in Setup Operator Node - 2. Initialize.

2. Running User Node

You must Setup User Node - 1. Initialize before running user node. It will use same datadir as in the initialization.

Run user node with following command. If you want to run challenger, add --rootchain.challenger 0x0... to the command.

plasma-evm$ build/bin/geth \
    --nousb \
    --datadir ./.pls.staking/usernode \
    --syncmode='full' \
    --networkid 102 \
    --rootchain.url ws://localhost:8546 \
    --rpc \
    --rpcaddr '0.0.0.0' \
    --rpcport 8547 \
    --rpcapi eth,net,debug \
    --rpccorsdomain '*' \
    --rpcvhosts=localhost \
    --ws \
    --wsorigins '*' \
    --wsaddr '0.0.0.0' \
    --wsport 8548 \
    --bootnodes "enode://4966a7e4621c2c0b1b1b3295b4a35ccc4224ba1d529bf5aa2323e4650f6075bd5eb6618372b2579965819347307f1f97315ce91b09ca342d60c2e98ad88db9f3@127.0.0.1:30306" \
    --port 30307 \
    --nat extip:::1 \
    --maxpeers 50

You must set syncmode to full or archive in order to synchronize with operator node.

Next

Try to send a simple transaction using JSON-RPC protocol to the usernode which setup in the previous step. If no transaction, The childchain, tokamak plasma, does not generate block due to Unique structure of the Tokamak network

Also, try to deploy requestable contract to both the rootchain and the childchain, and send some transaction with Enter and Exit. these process will help to understand a powerful interoperability of Tokamak network.

Last updated on 2020. 4. 16. by Jin
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