VictoriaMetrics/VictoriaMetrics · error

dial error: %w

Error message

dial error: %w

What it means

Fires in VMInsertClientWithDialer when the provided dial function fails to establish the TCP connection to the server before the handshake. The wrapped net error identifies DNS failure, connection refused, or timeout; the input at fault is the dialed address.

Source

Thrown at lib/handshake/handshake.go:39

	successResponse = "ok"
)

// Func must perform handshake on the given c using the given compressionLevel.
//
// It must return BufferedConn wrapper for c on successful handshake.
type Func func(c net.Conn, compressionLevel int) (*BufferedConn, error)

// VMInsertClientWithDialer performs client-side handshake for vminsert protocol.
//
// it uses provided dial func to establish connection to the server.
// compressionLevel is a legacy option which defines the level used for compression of the data sent
// to the server.
// compressionLevel <= 0 means 'no compression'
func VMInsertClientWithDialer(dial func() (net.Conn, error), compressionLevel int) (*BufferedConn, error) {
	c, err := dial()
	if err != nil {
		return nil, fmt.Errorf("dial error: %w", err)
	}
	bc, err := vminsertClient(c, 0)
	if err == nil {
		return bc, nil
	}
	_ = c.Close()
	// fallback only if vmstorage closed connection at read success response
	if !errors.Is(err, io.EOF) && !strings.Contains(err.Error(), "cannot read success response after sending hello") {
		return nil, err
	}
	// try to fallback to the prev non-RPC API version
	// we cannot re-use exist connection, since vmstorage already closed it
	c, err = dial()
	if err != nil {
		return nil, fmt.Errorf("dial error: %w", err)
	}
	bc, err = genericClient(c, vminsertHelloLegacyVersion, compressionLevel)
	if err != nil {

View on GitHub (pinned to 5079fb58f1)

Solutions

1. Verify the target address resolves and the port is open
2. Check firewall/security-group rules between client and server
3. Retry — transient network failures are common in mesh environments

When it happens

Trigger: Thrown at lib/handshake/handshake.go:39 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of VictoriaMetrics/VictoriaMetrics@5079fb58f1 (2026-09-03). Data as JSON: /api/errors/a7e1aee468aae8e8. Report an issue: GitHub.