Node
A node is a single Ethereum node in the blockchain network. Geth is installed as a Docker image.
The first node in the network to start up will immediately start generating blocks and creating a blockchain. The second and subsequent nodes in the network will send an add peers request to the first node, and if successful, they will start syncing data and eventually share the same blockchain data.
There are two types of nodes: Validator nodes, which can validate and seal (approve and sign) the contents of each block, and Relay nodes, which share the same blockchain data but cannot seal it. The Validator node is a trusted node, and is responsible for signing (sealing) the block when its turn comes, while building consensus through PoA. If the Validator node cannot be trusted, the reliability of the block for which it is responsible for the blockchain data is questionable.
Geth's PoA algorithm, based on Clique, can make a fraudulent transaction appear successful if even one untrusted node is present. In the future, we plan to support another Hyperleder Basu that uses a more secure consensus algorithm such as IBFT, which is Byzantine-resistant even if less than 1/3 of the nodes are hijacked.
The relay node is a node that does not participate in the consensus (does not have the right to sign the block), but shares the data in the transaction pool. However, it can return data and accept requests from users, and is intended to be used mainly as a reference node. When a request is received, the request is forwarded to the validator node.