From a47b85c8c4c80352287da8b87f8f46743cb0e74a Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 21 Apr 2014 20:39:48 -0700
Subject: [PATCH] synced_folders/rsync: add UserKnownHostsFile to /dev/null
 [GH-3511]

---
 CHANGELOG.md                           | 1 +
 plugins/synced_folders/rsync/helper.rb | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 160916142..3694635c5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,7 @@ BUG FIXES:
 
   - synced\_folders/nfs: Acquires a process-level lock so exports don't
       collide with Vagrant running in parallel.
+  - synced\_folders/rsync: Add UserKnownHostsFile option to not complain. [GH-3511]
 
 PLUGIN AUTHOR CHANGES:
 
diff --git a/plugins/synced_folders/rsync/helper.rb b/plugins/synced_folders/rsync/helper.rb
index a4c8d4b6a..c5c9e7da7 100644
--- a/plugins/synced_folders/rsync/helper.rb
+++ b/plugins/synced_folders/rsync/helper.rb
@@ -57,7 +57,9 @@ module VagrantPlugins
         username = ssh_info[:username]
         host     = ssh_info[:host]
         rsh = [
-          "ssh -p #{ssh_info[:port]} -o StrictHostKeyChecking=no",
+          "ssh -p #{ssh_info[:port]} " +
+          "-o StrictHostKeyChecking=no " +
+          "-o UserKnownHostsFile=/dev/null",
           ssh_info[:private_key_path].map { |p| "-i '#{p}'" },
         ].flatten.join(" ")