# Join the Cosmos Hub Mainnet

See the launch repo for information on the mainnet, including the correct version of the Cosmos-SDK to use and details about the genesis file.

You need to install gaia before you go further

# Setting Up a New Node

These instructions are for setting up a brand new full node from scratch.

First, initialize the node and create the necessary config files:

Copy gaiad init <your_custom_moniker>

Note

Monikers can contain only ASCII characters. Using Unicode characters will render your node unreachable.

You can edit this moniker later, in the ~/.gaiad/config/config.toml file:

Copy # A custom human readable name for this node moniker = "<your_custom_moniker>"

You can edit the ~/.gaiad/config/app.toml file in order to enable the anti spam mechanism and reject incoming transactions with less than the minimum gas prices:

Copy # This is a TOML config file. # For more information, see https://github.com/toml-lang/toml ##### main base config options ##### # The minimum gas prices a validator is willing to accept for processing a # transaction. A transaction's fees must meet the minimum of any denomination # specified in this config (e.g. 10uatom). minimum-gas-prices = ""

Your full node has been initialized!

# Genesis & Seeds

# Copy the Genesis File

Fetch the mainnet's genesis.json file into gaiad's config directory.

Copy mkdir -p $HOME/.gaiad/config curl https://raw.githubusercontent.com/cosmos/launch/master/genesis.json > $HOME/.gaiad/config/genesis.json

Note we use the latest directory in the launch repo which contains details for the mainnet like the latest version and the genesis file.

If you want to connect to the public testnet instead, click here

To verify the correctness of the configuration run:

Copy gaiad start

# Add Seed Nodes

Your node needs to know how to find peers. You'll need to add healthy seed nodes to $HOME/.gaiad/config/config.toml. The launch repo contains links to some seed nodes.

If those seeds aren't working, you can find more seeds and persistent peers on a Cosmos Hub explorer (a list can be found on the launch page).

You can also ask for peers on the Validators Riot Room

For more information on seeds and peers, you can read this.

# A Note on Gas and Fees

On Cosmos Hub mainnet, the accepted denom is uatom, where 1atom = 1.000.000uatom

Transactions on the Cosmos Hub network need to include a transaction fee in order to be processed. This fee pays for the gas required to run the transaction. The formula is the following:

Copy fees = ceil(gas * gasPrices)

The gas is dependent on the transaction. Different transaction require different amount of gas. The gas amount for a transaction is calculated as it is being processed, but there is a way to estimate it beforehand by using the auto value for the gas flag. Of course, this only gives an estimate. You can adjust this estimate with the flag --gas-adjustment (default 1.0) if you want to be sure you provide enough gas for the transaction.

The gasPrice is the price of each unit of gas. Each validator sets a min-gas-price value, and will only include transactions that have a gasPrice greater than their min-gas-price.

The transaction fees are the product of gas and gasPrice. As a user, you have to input 2 out of 3. The higher the gasPrice/fees, the higher the chance that your transaction will get included in a block.

For mainnet, the recommended gas-prices is 0.025uatom.

# Set minimum-gas-prices

Your full-node keeps unconfirmed transactions in its mempool. In order to protect it from spam, it is better to set a minimum-gas-prices that the transaction must meet in order to be accepted in your node's mempool. This parameter can be set in the following file ~/.gaiad/config/app.toml.

The initial recommended min-gas-prices is 0.025uatom, but you might want to change it later.

# Pruning of State

There are three strategies for pruning state, please be aware that this is only for state and not for block storage:

  1. PruneEverything: This means that all saved states will be pruned other than the current.
  2. PruneNothing: This means that all state will be saved and nothing will be deleted.
  3. PruneSyncable: This means that only the state of the last 100 and every 10,000th blocks will be saved.

By default every node is in PruneSyncable mode. If you would like to change your nodes pruning strategy then you must do so when the node is initialized. For example, if you would like to change your node to the PruneEverything mode then you can pass the ---pruning everything flag when you call gaiad start.

Note: When you are pruning state you will not be able to query the heights that are not in your store.

# Run a Full Node

Start the full node with this command:

Copy gaiad start

Check that everything is running smoothly:

Copy gaiacli status

View the status of the network with the Cosmos Explorer.

# Export State

Gaia can dump the entire application state to a JSON file, which could be useful for manual analysis and can also be used as the genesis file of a new network.

Export state with:

Copy gaiad export > [filename].json

You can also export state from a particular height (at the end of processing the block of that height):

Copy gaiad export --height [height] > [filename].json

If you plan to start a new network from the exported state, export with the --for-zero-height flag:

Copy gaiad export --height [height] --for-zero-height > [filename].json

# Verify Mainnet

Help to prevent a catastrophe by running invariants on each block on your full node. In essence, by running invariants you ensure that the state of mainnet is the correct expected state. One vital invariant check is that no atoms are being created or destroyed outside of expected protocol, however there are many other invariant checks each unique to their respective module. Because invariant checks are computationally expensive, they are not enabled by default. To run a node with these checks start your node with the assert-invariants-blockly flag:

Copy gaiad start --assert-invariants-blockly

If an invariant is broken on your node, your node will panic and prompt you to send a transaction which will halt mainnet. For example the provided message may look like:

Copy invariant broken: loose token invariance: pool.NotBondedTokens: 100 sum of account tokens: 101 CRITICAL please submit the following transaction: gaiacli tx crisis invariant-broken staking supply

When submitting a invariant-broken transaction, transaction fee tokens are not deducted as the blockchain will halt (aka. this is a free transaction).

# Upgrade to Validator Node

You now have an active full node. What's the next step? You can upgrade your full node to become a Cosmos Validator. The top 125 validators have the ability to propose new blocks to the Cosmos Hub. Continue onto the Validator Setup.