diff --git a/runtime/v2/shim.go b/runtime/v2/shim.go index f4265c17f695..e04fad2635e3 100644 --- a/runtime/v2/shim.go +++ b/runtime/v2/shim.go @@ -22,6 +22,7 @@ import ( "errors" "fmt" "io" + "net" "os" "path/filepath" "strings" @@ -253,7 +254,7 @@ func makeConnection(ctx context.Context, params client.BootstrapParams, onClose grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithBlock(), } - return grpcDialContext(ctx, dialer.DialAddress(params.Address), onClose, gopts...) + return grpcDialContext(ctx, params.Address, onClose, gopts...) default: return nil, fmt.Errorf("unexpected protocol: %q", params.Protocol) } @@ -264,10 +265,29 @@ func makeConnection(ctx context.Context, params client.BootstrapParams, onClose // a callback run when the connection is severed or explicitly closed. func grpcDialContext( ctx context.Context, - target string, + address string, onClose func(), gopts ...grpc.DialOption, ) (*grpcConn, error) { + // If grpc.WithBlock is specified in gopts this causes the connection to block waiting for + // a connection regardless of if the socket exists or has a listener when Dial begins. This + // specific behavior of WithBlock is mostly undesirable for shims, as if the socket isn't + // there when we go to load/connect there's likely an issue. However, getting rid of WithBlock is + // also undesirable as we don't want the background connection behavior, we want to ensure + // a connection before moving on. To bring this in line with the ttrpc connection behavior + // lets do an initial dial to ensure the shims socket is actually available. stat wouldn't suffice + // here as if the shim exited unexpectedly its socket may still be on the filesystem, but it'd return + // ECONNREFUSED which grpc.DialContext will happily trudge along through for the full timeout. + // + // This is especially helpful on restart of containerd as if the shim died while containerd + // was down, we end up waiting the full timeout. + conn, err := net.DialTimeout("unix", address, time.Second*10) + if err != nil { + return nil, err + } + conn.Close() + + target := dialer.DialAddress(address) client, err := grpc.DialContext(ctx, target, gopts...) if err != nil { return nil, fmt.Errorf("failed to create GRPC connection: %w", err)