diff --git a/metropolis/pkg/pki/ca.go b/metropolis/pkg/pki/ca.go
index 4931b5e..7c03f9f 100644
--- a/metropolis/pkg/pki/ca.go
+++ b/metropolis/pkg/pki/ca.go
@@ -60,7 +60,7 @@
 
 	req.Template.SerialNumber = serialNumber
 	req.Template.NotBefore = time.Now()
-	req.Template.NotAfter = unknownNotAfter
+	req.Template.NotAfter = UnknownNotAfter
 	req.Template.BasicConstraintsValid = true
 	req.Template.SubjectKeyId = skid