CBSA Solution Deployment & Integration 5 — Questions and Answers
Question 1: A blockchain architect must design a rollback strategy for a failed chaincode upgrade. What is the correct approach in Hyperledger Fabric?
- Delete all blocks since the upgrade and replay from the previous state
- Re-deploy the previous approved chaincode version using the lifecycle endorsement process (Correct answer)
- Reset the peer nodes to factory defaults
- Manually edit the world state database to revert changes
Correct answer: Re-deploy the previous approved chaincode version using the lifecycle endorsement process
Hyperledger Fabric's chaincode lifecycle allows a previous approved and committed chaincode version to be re-instantiated without altering the immutable ledger history.
Question 2: When integrating a blockchain solution with an enterprise message broker (e.g., Apache Kafka), what is the primary architectural benefit?
- Kafka replaces the blockchain's consensus mechanism
- Kafka decouples blockchain event producers from consumers, enabling scalable, fault-tolerant event-driven integration (Correct answer)
- Kafka stores the blockchain ledger off-chain for faster queries
- Kafka eliminates the need for smart contract logic
Correct answer: Kafka decouples blockchain event producers from consumers, enabling scalable, fault-tolerant event-driven integration
Using Kafka as a message broker decouples blockchain event emission from downstream consumers, enabling independent scaling, replay, and fault tolerance.
Question 3: A Hyperledger Fabric deployment uses private data collections. What is their primary purpose in a multi-organization channel?
- To encrypt all ledger data from the ordering service
- To allow a subset of organizations to share confidential data without exposing it to the full channel (Correct answer)
- To increase transaction throughput by reducing block size
- To replace the need for separate channels for different data sensitivity levels
Correct answer: To allow a subset of organizations to share confidential data without exposing it to the full channel
Private data collections allow a defined subset of channel members to store and access sensitive data off-chain while only a hash is recorded on the shared ledger.
Question 4: During integration testing of a blockchain solution, a team uses Hyperledger Fabric's test network. Which statement about this environment is correct?
- The test network is production-grade and can be used for live deployments
- The test network uses a pre-configured CA, orderer, and peers suitable for development and integration testing only (Correct answer)
- The test network requires a Kubernetes cluster to operate
- The test network supports Byzantine Fault Tolerant consensus by default
Correct answer: The test network uses a pre-configured CA, orderer, and peers suitable for development and integration testing only
Fabric's test network provides a minimal pre-configured network for development and integration testing and is explicitly not intended for production use.
Question 5: A blockchain architect needs to ensure that a deployed Ethereum smart contract handles failed external calls safely. Which Solidity pattern prevents a single failed call from reverting all state changes?
- Using a single require() statement wrapping all external calls
- Implementing the pull-over-push payment pattern to let recipients withdraw funds independently (Correct answer)
- Wrapping all logic in an unchecked block
- Deploying multiple identical contracts and calling each one sequentially
Correct answer: Implementing the pull-over-push payment pattern to let recipients withdraw funds independently
The pull pattern shifts fund withdrawal responsibility to recipients, so one recipient's failed receive function cannot block or revert other participants' state changes.
Question 6: Which monitoring metric is most critical for detecting blockchain network health issues in a production Hyperledger Fabric deployment?
- Number of registered users in the Certificate Authority
- Transaction endorsement failure rate and block commit latency across peer nodes (Correct answer)
- Size of the chaincode Docker image
- Number of channels configured on the network
Correct answer: Transaction endorsement failure rate and block commit latency across peer nodes
Endorsement failure rate and block commit latency directly indicate whether the network is processing transactions correctly and within acceptable performance bounds.
Question 7: A company deploys a blockchain solution and needs disaster recovery. Which recovery time objective (RTO) factor is unique to blockchain compared to traditional databases?
- Blockchain data cannot be backed up
- Recovering a blockchain node requires re-syncing the full ledger history from peers, which takes longer than restoring from a point-in-time snapshot alone (Correct answer)
- Blockchain networks have no single point of failure, making disaster recovery unnecessary
- Only the organization that created the genesis block can restore the network
Correct answer: Recovering a blockchain node requires re-syncing the full ledger history from peers, which takes longer than restoring from a point-in-time snapshot alone
Unlike a database restore from backup, a blockchain peer must validate and sync all historical blocks from the network, significantly impacting RTO for large ledgers.
CBSA Solution Deployment & Integration 5
A blockchain architect must design a rollback strategy for a failed chaincode upgrade.
What is the correct approach in Hyperledger Fabric?