starting a genesis blockchain

When starting a genesis praos blockchain there is an element to take into consideration while constructing the block 0: the stake distribution.

In the context of Genesis/Praos the network is fully decentralized and it is necessary to think ahead about initial stake pools and to make sure there is stake delegated to these stake pools.

In your genesis yaml file, make sure to set the following values to the appropriate values/desired values:

# The Blockchain Configuration defines the settings of the blockchain.
blockchain_configuration:
  block0_consensus: genesis_praos
  consensus_genesis_praos_active_slot_coeff: 0.1
  kes_update_speed: 43200 # 12hours

block0_consensus set to genesis_praos means you want to start a blockchain with genesis praos as the consensus layer.

consensus_genesis_praos_active_slot_coeff determines minimum stake required to try becoming slot leader, must be in range 0 exclusive and 1 inclusive.

The initial certificates

In the initial_certs field you will set the initial certificate. It is important to declare the stake pool and delegate stake to them. Otherwise no block will ever be created.

Remember that in this array the order matters:

In order to delegate your stake, you need a stake pool to already exist, so the stake pool registration certificate should go first.

Stake pool registration

Now you can register a stake pool. Follow the instructions in registering stake pool guide.

The owner key (the key you sign the stake pool registration certificate) is the secret key associated to a previously registered stake key.

Delegating stake

Now that there is both your stake key and there are stake pools available in the block0 you need to delegate to one of the stake pool. Follow the instruction in delegating stake.

And in the initial funds start adding the addresses. To create an address with delegation follow the instruction in JCLI's address guide. Utilise the stake key registered previously as group address:

jcli address single $(cat wallet_key.pub) $(cat stake_key.pub)
ta1sjx4j3jwel94g0cgwzq9au7h6m8f5q3qnyh0gfnryl3xan6qnmjse3k2uv062mzj34eacjnxthxqv8fvdcn6f4xhxwa7ms729ak3gsl4qrq2mm

You will notice that addresses with delegation are longer (about twice longer) than addresses without delegation.

For example, the most minimal setting you may have is:

initial_certs:
  # register a stake pool (P), owner of the stake pool is the stake key (K)
  - cert1qsqqqqqqqqqqqqqqqqqqq0p5avfqp9tzusr26chayeddkkmdlap6tl23ceca8unsghc22tap8clhrzslkehdycufa4ywvqvs4u36zctw4ydtg7xagprfgz0vuujh3lgtxgfszqzqj4xk4sxxyg392p5nqz8s7ev5wna7eqz7ycsuas05mrupmdsfk0fqqudanew6c0nckf5tsp0lgnk8e8j0dpnxvjk2usn52vs8umr3qrccegxaz

  # delegate stake associated to stake key (K) to stake pool (P)
  - cert1q0rv4ccl54k99rtnm39xvhwvqcwjcm385n2dwvamahpu5tmdz3plt65rpewev3a03xj7nfx5pz0xap2cjxjnxvt2ma9y9dalzder3xm5qyqyq0lx05ggrws0ghuffqrg7scqzdsd665v4m7087eam5zvw4f26v2tsea3ujrxly243sgqkn42uttk5juvq78ajvfx9ttcmj05lfuwtq9qhdxzr0

initial_funds:
  # address without delegation
  - address: ta1swx4j3jwel94g0cgwzq9au7h6m8f5q3qnyh0gfnryl3xan6qnmjsczt057x
    value: 10000
  # address delegating to stake key (K)
  - address: ta1sjx4j3jwel94g0cgwzq9au7h6m8f5q3qnyh0gfnryl3xan6qnmjse3k2uv062mzj34eacjnxthxqv8fvdcn6f4xhxwa7ms729ak3gsl4qrq2mm
    value: 1000000

Starting the node

Now, to start the node and be able to generate new blocks, you have to put your pool's private keys and id in a file and start the node with the --secret filename parameter.

For example, if you follow the examples of the registering stake pool guide

You could create a file called poolsecret.yaml with the following content.

genesis:
  sig_key: Content of stake_pool_kes.prv file
  vrf_key: Content of stake_pool_vrf.prv file
  node_id: Content of stake_pool.id file

And you could start the node with this command

jormungandr --genesis-block block-0.bin --config config.yaml --secret poolsecret.yaml

Test script

There is a script here that can be used to bootstrap a test node with a pre-set faucet and stake pool and can be used as an example.