Troubleshooting & Problem Resolution Flashcards

A transaction is committed to a block but flagged ENDORSEMENT_POLICY_FAILURE. What is the most likely cause?

Answer: The transaction lacked endorsements from the organizations the chaincode endorsement policy requires

Validation at commit checks collected endorsements against the endorsement policy, and missing required orgs invalidates the transaction.

Two transactions in the same block read and update the same key, and the second is marked MVCC_READ_CONFLICT. What is the correct resolution?

Answer: Resubmit the second transaction as a new proposal so it reads the updated key version

The read version became stale when the first transaction committed, so the client must retry with a fresh proposal.

A peer logs 'access denied: channel creator org unknown' when Org3 tries to use a channel. What is the proper fix?

Answer: Add Org3 to the channel configuration through a config update transaction

An organization must be present in the channel config with its MSP definition before its identities are accepted.

A 3-node Raft ordering service reports no leader after two orderers go offline. Why?

Answer: A majority quorum (2 of 3) is no longer available, so no leader can be elected

Raft needs a majority of consenters to elect a leader and commit entries.

An invoke fails with 'context deadline exceeded' while the chaincode runs a long computation. Which setting is most relevant?

Answer: The chaincode execute timeout in the peer's core.yaml

The peer enforces chaincode.executetimeout (default 30s) on each chaincode invocation.

After an unclean shutdown a peer's state database is inconsistent with its block store. Which action is the standard recovery?

Answer: Run peer node rebuild-dbs so state is rebuilt from the block store

rebuild-dbs drops the state and history databases so they are reconstructed from the committed blocks.

Peers fail with 'x509: certificate has expired or is not yet valid' although certificates were just issued. What should you check first?

Answer: System clock synchronization on the hosts and the certificate validity dates

Clock skew or genuinely expired TLS/MSP certificates produce this exact x509 validation error.