What is true about the historic states in Hyperledger Fabric model?
C
Explanation:
Historic states in the Hyperledger Fabric ledger are immutable, meaning they cannot be altered after
they have been committed to the ledger. This immutability ensures the integrity and traceability of
all transactions on the network. Once a transaction is recorded, it is permanent, and its history can
be audited to trace back all operations affecting any piece of data. This feature is fundamental in
blockchain technology, providing a verifiable and tamper-evident record. The immutability of historic
states is a key component of the trust and security model in Hyperledger Fabric, contrary to options
that suggest these records can be modified or are inaccessible.
In Hyperledger Fabric, Intercommunication is how a smart contract in a channel updates the World
State database. It is achieved by what process?
C
Explanation:
Intercommunication in Hyperledger Fabric regarding how smart contracts update the World State
database is primarily achieved by calling other smart contracts, both within the same channel and
across different channels. This process allows smart contracts, also known as chaincode, to interact
and transact across the network, updating the World State as necessary based on business logic
defined in the contracts. This capability is crucial for complex business processes that span multiple
contracts and possibly multiple channels. Unlike setting endorsement policies or configuring peer-to-
peer options, calling other smart contracts directly facilitates dynamic and direct interaction between
business processes, enhancing the modularity and efficiency of the network. Cross-channel
communication must be carefully managed within the permissions and policies defined in the
network to maintain security and integrity.
What types of events committed to the ledger can client applications receive using the peer's event
service?
B
Explanation:
In Hyperledger Fabric, client applications can subscribe to receive both chaincode events and block
events using the peer's event service. Chaincode events are generated by the chaincode itself,
typically based on specific conditions coded within the chaincode operations, and are used to notify
applications of specific state changes or significant occurrences. Block events inform about the
addition of new blocks to the ledger, which may contain multiple transactions. This dual capability
allows client applications to effectively monitor transaction confirmations and specific chaincode
outputs in real time, which is critical for applications that rely on up-to-date blockchain data for
processing decisions.
Which of the following is the correct role of orderer nodes?
A
Explanation:
The primary role of orderer nodes in Hyperledger Fabric is to order and package endorsed
transactions into blocks. Orderers receive transactions from various peers, ensure that these
transactions are in a consistent order, and then package them into blocks that are subsequently
appended to the blockchain. This function is crucial for maintaining the consistency and integrity of
the ledger across all participating nodes. Orderer nodes do not issue tokens, enforce peer
endorsements, or reorder stored blocks for data compression. Instead, their main function is integral
to the consensus and ledger maintenance processes within a Hyperledger Fabric network
What gRPC status code might you expect to be associated with an error invoking a transaction as a
result of a transient failure, such as a network disconnection between the client application and
Gateway peer?
A
Explanation:
The gRPC status code "UNAVAILABLE" is commonly expected in scenarios involving transient failures
in network communication, such as a disconnection between the client application and the Gateway
peer. This status code indicates that the service is currently unavailable, often due to network issues
or service downtime, making it suitable for situations where the failure is temporary and the request
can be retried. This differs from other codes like "ABORTED" or "DEADLINE EXCEEDED," which
represent different types of errors related to the transaction logic or timing issues, respectively.
"FAILED PRECONDITION" would be inappropriate for network disconnections as it suggests issues
with the request's preconditions, not the network status.
In a production environment, what peer items require on-going monitoring?
C
Explanation:
In a production environment of Hyperledger Fabric, it is essential to monitor all peer containers
comprehensively, including their CPU, network, and memory usage. This is because each peer node
plays a critical role in maintaining the network's overall health and efficiency. Monitoring these
resources helps in detecting potential bottlenecks or failures early, ensuring the smooth operation of
the blockchain network. Focusing only on specific components like the orderer service or chaincode
containers would provide a limited view of the network's health and could lead to issues being
overlooked. Comprehensive monitoring enables administrators to maintain optimal performance
and reliability across the entire network.
What do we call the ordering nodes actively participating in the consensus mechanism for a given
channel and receiving replicated logs for the channel?
B
Explanation:
In Hyperledger Fabric, the ordering nodes that are actively participating in the consensus mechanism
for a given channel are referred to as the "Consenter set." These nodes are part of the ordering
service and are responsible for creating blocks by ordering transactions and ensuring consistency
across the network. The Consenter set receives the transaction logs that need to be replicated across
other orderers and peers in the network. This is distinct from the "Committer set," which comprises
nodes that commit blocks to their ledger, and "Endorsers," which are responsible for endorsing
transactions by checking them against the chaincode execution policies.
Which of the following is the identity solution in Hyperledger Fabric?
D
Explanation:
In Hyperledger Fabric, the identity solution that manages user identities and authenticates
participants on the network is facilitated by Membership Service Providers (MSPs). MSPs are crucial
for defining the rules by which identities are validated, authenticated, and allowed access to the
network. MSPs handle the issuance of certificates and define the roles and permissions associated
with participant identities, enabling permissioned interactions on the blockchain. This differs from
Hyperledger Fabric CA, which primarily issues and revokes certificates as part of identity
management but is used in conjunction with MSPs to provide comprehensive identity solutions
within the network.
What is necessary for a chaincode to become ready to commit on a channel?
C
Explanation:
For a chaincode to become ready to commit on a channel in Hyperledger Fabric, it is necessary that
the policy "/Channel/Application/LifecycleEndorsement" be satisfied. This policy specifies who needs
to approve the chaincode definition before it can be committed to the channel. It ensures that the
chaincode deployment is endorsed according to the governance standards agreed upon by the
network participants, typically requiring a majority or other specified fraction of the organizations in
the network to endorse the change. This lifecycle endorsement policy is key to maintaining a secure
and agreed-upon update process for chaincodes on the channel.
How can the client application access descriptive error text for each of the endorsing peers following
a transaction endorsement failure?
D
Explanation:
When a client application encounters a transaction endorsement failure in Hyperledger Fabric, the
most effective way to access descriptive error text for each endorsing peer is to extract the details
associated with the returned error. This error information typically includes details about why the
endorsement was unsuccessful, providing insights into issues such as policy violations or execution
failures. This method is more direct and informative compared to extracting logs or examining
generic error messages and helps developers and administrators quickly diagnose and address issues
in transaction processing.