diff --git a/README.md b/README.md
index f52ae44a6a13e08117f2980a1e93f64568bf4646..848b9210d7af27b2d4e3c29c6608ae1e67f93735 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,12 @@ docker exec -ti rweb /bin/bash
 |30997|FRPC console|
 |30500-30899|FRP server dynamic ports|
 
+## tw1 migration (gcp)
+
+run `ssh-keygen -A` by serial after setup the new machine.
+
+--------
+
 ## recolic.net
 
 fresh deploy: