Kafka. The Kafka ordering service leverages a cluster of Kafka brokers and a Zookeeper ensemble to provide for a crash fault tolerant (CFT) ordering service. It is possible for your ordering service to consist of several ordering nodes that are under the control of different organizations on your network.

Simply so, what's the purpose of the ordering service?

These ordering service nodes work together to collectively form the ordering service. Its job is to arrange batches of submitted transactions into a well-defined sequence and package them into blocks. These blocks will become the blocks of the blockchain!

Secondly, what is Kafka in Hyperledger? Introduction. Kafka is primarily a distributed, horizontally-scalable, fault-tolerant, commit log. A commit log is basically a data structure that only appends. There can be multiple Kafka nodes in the blockchain network, with their corresponding Zookeeper ensemble.

Beside above, what is ordering service in Hyperledger fabric?

The ordering service accepts the endorsed transactions and specifies the order in which those transactions will be committed to the ledger. The Fabric v1. 0 architecture has been designed such that the specific implementation of 'ordering' (Solo, Kafka, BFT) becomes a pluggable component.

What is Kafka consensus?

Consensus in blockchain involves nodes agreeing on the same order of transactions. Ordering nodes send to Kafka transactions, and receive from Kafka transactions in the same order, since Kafka presents an abstraction of a shared queue. All orderers create blocks when they read enough messages or enough data from kafka.

How is data stored in a ledger?

The blockchain ledger serves as a decentralized database that maintains details about each transaction. The transactions are added to the ledger in chronological order and stored as a series of blocks. The ledger is distributed across multiple nodes, with each node maintaining a complete copy.

How is data stored in a ledger Hyperledger?

the blockchain data, aka the ledger, is stored as a physical file. it contains linked blocks, each block consisting of a set of transactions. Each state change is stored there. when a new peer gets added to a channel, its own world state is created from the ledger.

What are the two types of nodes in Hyperledger fabric?

There are three types of nodes:
  • Client or submitting-client: a client that submits an actual transaction-invocation to the endorsers, and broadcasts transaction-proposals to the ordering service.
  • Peer: a node that commits transactions and maintains the state and a copy of the ledger (see Sec, 1.2).

What are the four stages of a chain code life cycle?

We provide four commands to manage a chaincode's lifecycle: package , install , instantiate , and upgrade . In a future release, we are considering adding stop and start transactions to disable and re-enable a chaincode without having to actually uninstall it.

Which tool is used to create configurations?

The configtxgen tool is used to create four configuration artifacts: orderer genesis block , channel configuration transaction , and two anchor peer transactions - one for each Peer Org.

How many peers in the network need to endorse a transaction?

Sufficient number of endorsements Deciding which organisations and peers should endorse a transaction is a business requirement, not a technical one. If the transaction affects only two organisations, then why have three or four organisations be part of the endorsement policy.

How does Hyperledger fabric work?

Hyperledger Fabric is a permissioned blockchain network that gets set by the organizations that intend to set up a consortium. The client application uses Hyperledger Fabric SDK or REST web service to interact with the Hyperledger Fabric network.

What do channels provide between different ledgers?

There is a different ledger for each channel, as channels enforce chaincode and data isolation. Channels allow participants to establish a communication path between the subset of participants that have permissions to visualize a subset of transactions.

What is the default programming language used by Hyperledger fabric?

Golang

Which tool is used to view invoke deploy or query a block in a ledger?

Hyperledger Explorer

What does the Cryptogen tool help you create?

cryptogen is an utility for generating Hyperledger Fabric key material. It is provided as a means of preconfiguring a network for testing purposes. It would normally not be used in the operation of a production network.

What is the consensus algorithm used by ethereum?

Current Protocol: Proof of Work (Ethash) The current Ethereum blockchain uses a consensus algorithm built specifically for the Ethereum blockchain called Ethash. The Ethash PoW algorithm introduces the property of “Memory Hardness” to the Ethereum blockchain.

Which consensus algorithm is used by Hyperledger fabric?

Consensus Algorithm Used in Hyperledger Fabric: Solo – It is a Hyperledger Fabric ordering mechanism most typically used by developers experimenting with Hyperledger Fabric networks. SOLO involves a single ordering node. It is not used in production environment.

What is a subnet of communication between members of a Blockchain network?

A transaction is an asset transfer onto or off of the ledger. In a Hyperledger Fabric blockchain, a channel is a private “subnet” of communication between two or more specific network members, for the purpose of conducting private and confidential transactions.

Which of the following components are modular in Hyperledger fabric?

At a high level, Fabric is comprised of the following modular components:
  • A pluggable ordering service establishes consensus on the order of transactions and then broadcasts blocks to peers.
  • A pluggable membership service provider is responsible for associating entities in the network with cryptographic identities.

Which of the following functions are supported by fabric CA?

FYI, Fabric CA provides features such as:
  • Registration of identities with roles like peer or connects to an existing LDAP as the user registry to fetch identities of the mentioned roles.
  • Issuance of Enrollment Certificates for signing and identifying.
  • Issuance of Transaction Certificates.

At what stage's in the transaction flow can the endorsement policies be validated?

After the ordering phase, there's a validation phase. In this phase, transactions are validated by the committing peers according to the endorsement policy and check whether the transaction is still valid for the current world state.