diff --git a/src/cmd/linuxkit/pkglib/docker.go b/src/cmd/linuxkit/pkglib/docker.go
index b467ce8bc..f3d377ad3 100644
--- a/src/cmd/linuxkit/pkglib/docker.go
+++ b/src/cmd/linuxkit/pkglib/docker.go
@@ -75,7 +75,7 @@ func (dr dockerRunner) pushWithManifest(img, suffix string) error {
 		return err
 	}
 
-	dctArg := "0"
+	var dctArg string
 	if dr.dct {
 		dctArg = "1"
 	}