hashicorp/nomad · error

failed updating variable index: %s

Error message

failed updating variable index: %s

What it means

Returned by varSetTxn after the variable and quota rows are written, when updating the TableVariables index entry (IndexEntry for TableVariables) via tx.Insert fails. The index tracks the latest ModifyIndex for the variables table; failing this aborts the whole variable write with an ErrorResponse. It wraps the underlying memdb error.

Source

Thrown at nomad/state/state_store_variables.go:294

	err = s.enforceVariablesQuota(idx, tx, sv.Namespace, quotaChange)
	if err != nil {
		return req.ErrorResponse(idx, err)
	}

	// we check enforcement above even if there's no change because another
	// namespace may have used up quota to make this no longer valid, but we
	// only update the table if this namespace has changed
	if quotaChange != 0 {
		quotaUsed.ModifyIndex = idx
		if err := tx.Insert(TableVariablesQuotas, quotaUsed); err != nil {
			return req.ErrorResponse(idx, fmt.Errorf("variable quota insert failed: %v", err))
		}
	}

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

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

// VarDelete is used to delete a single variable in the
// the state store.
func (s *StateStore) VarDelete(msgType structs.MessageType, idx uint64, req *structs.VarApplyStateRequest) *structs.VarApplyStateResponse {
	tx := s.db.WriteTxnMsgT(msgType, idx)
	defer tx.Abort()

	// Perform the actual delete
	resp := s.svDeleteTxn(tx, idx, req)
	if !resp.IsOk() {
		return resp
	}

	err := tx.Commit()

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Read the wrapped %s error to determine the memdb cause
2. Retry the variable write; the aborted txn left the store unchanged
3. Check/restore state store integrity if the error persists
4. Report/upgrade if it's a known memdb issue

Example fix

// before
return req.ErrorResponse(idx, fmt.Errorf("failed updating variable index: %s", err))
// after
return req.ErrorResponse(idx, fmt.Errorf("failed updating variable index: %w", err))

if err != nil && strings.Contains(err.Error(), "failed updating variable index") {
    // whole write aborted; safe to retry
    return backoff.Retry(writeFn, backoff.WithMaxRetries(3))
}

When it happens

Trigger: Any successful VarSet / varSetCASTxn / VarLockAcquire path reaching the final index update where tx.Insert(tableIndex, &IndexEntry{TableVariables, idx}) errors — usually an aborted transaction or internal memdb failure.

Common situations: Long-running write transaction hitting a timeout or abort; corrupted index table; concurrent txn misuse in custom code reusing the store.

Related errors

• index update failed: %v
• index update failed: %v
• csi_plugin lookup error: %s %v
• csi_plugins insert error: %v
• csi_plugins lookup failed: %v

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/6685f953d6d0fbbf. Report an issue: GitHub.