hashicorp/nomad · error

failed lock release: %s

Error message

failed lock release: %s

What it means

VarLockRelease found the variable, copied it, cleared the Lock and bumped ModifyIndex, then called updateVarsAndIndexTxn to persist. This error wraps a failure of that persistence step (insert into variables table or index update inside the same write txn). The variable remains locked because the transaction was aborted (note the source also drops the return value of updateVarsAndIndexTxn, leaving the defer'd tx.Abort to roll back).

Source

Thrown at nomad/state/state_store_variables.go:565

			VariableMetadata: structs.VariableMetadata{
				Namespace: sv.Namespace,
				Path:      sv.Path,
				Lock:      &structs.VariableLock{},
			},
		}
		return req.ConflictResponse(idx, zeroVal)
	}

	// Avoid overwriting the variable data when releasing the lock, to prevent
	// a delay release to remove customer data.

	updated := sv.Copy()
	updated.Lock = nil
	updated.ModifyIndex = idx

	err = s.updateVarsAndIndexTxn(tx, idx, &updated)
	if err != nil {
		req.ErrorResponse(idx, fmt.Errorf("failed lock release: %s", err))
	}

	if err := tx.Commit(); err != nil {
		return req.ErrorResponse(idx, err)
	}

	return req.SuccessResponse(idx, &updated.VariableMetadata)
}

func (s *StateStore) updateVarsAndIndexTxn(tx WriteTxn, idx uint64, sv *structs.VariableEncrypted) error {
	if err := tx.Insert(TableVariables, sv); err != nil {
		return fmt.Errorf("failed inserting variable: %w", err)
	}

	if err := tx.Insert(tableIndex,
		&IndexEntry{TableVariables, idx}); err != nil {
		return fmt.Errorf("failed updating variable index: %w", err)
	}

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Inspect the wrapped cause for 'failed inserting variable' or 'failed updating variable index' details and check server logs at the same idx.
2. Free disk space / fix filesystem errors on the Nomad data_dir volume.
3. Restore state from a good snapshot if BoltDB is corrupt (nomad operator snapshot restore).
4. Retry the lock release after the store is healthy; the aborted txn guarantees no partial write.

Example fix

// before (library code even drops the error return)
err = s.updateVarsAndIndexTxn(tx, idx, &updated)
if err != nil { req.ErrorResponse(idx, fmt.Errorf("failed lock release: %s", err)) }
// after
if err := s.updateVarsAndIndexTxn(tx, idx, &updated); err != nil {
  return req.ErrorResponse(idx, fmt.Errorf("failed lock release: %w", err))
}

func isLockReleaseWriteFailure(err error) bool { return err != nil && strings.Contains(err.Error(), "failed lock release") }

err := s.state.VarLockRelease(allocID, path, ns)
if isLockReleaseWriteFailure(err) {
  // txn aborted atomically; safe to retry after storage is healthy
  backoff.Retry(func() error { return releaseLock(allocID, path, ns) }, backoffCfg)
}

When it happens

Trigger: tx.Insert into TableVariables or tableIndex fails inside updateVarsAndIndexTxn while applying OpReleaseLock in VarLockRelease; called from applyVariableOperation during FSM apply of a variable lock-release operation.

Common situations: Disk-full or IO errors on the server's data directory corrupting BoltDB writes; allocator/txn panics; multiple servers with divergent Raft state after an unclean shutdown.

Related errors

• error querying plugin %q: %v
• index update failed: %v
• JobByID lookup failed: %w
• UpsertJob failed: %w
• index update failed: %v

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/a59d1132b09ed7e0. Report an issue: GitHub.