From f32d9879dce4588082fc083e5f1f016caadeeeb2 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Fri, 5 Sep 2014 11:13:54 -0700
Subject: [PATCH] builder/docker: error if DOCKER_HOST is set

---
 CHANGELOG.md                    | 1 +
 builder/docker/driver_docker.go | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0f243c221..4d7cd6843 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -55,6 +55,7 @@ BUG FIXES:
   * builder/amazon/all: Fix race condition on setting tags. [GH-1367]
   * builder/amazon/all: More desctriptive error messages if Amazon only
       sends an error code. [GH-1189]
+  * builder/docker: Error if `DOCKER_HOST` is set.
   * builder/docker: Remove the container during cleanup. [GH-1206]
   * builder/docker: Fix case where not all output would show up from
       provisioners.
diff --git a/builder/docker/driver_docker.go b/builder/docker/driver_docker.go
index 737a5ff43..0169975f5 100644
--- a/builder/docker/driver_docker.go
+++ b/builder/docker/driver_docker.go
@@ -220,5 +220,10 @@ func (d *DockerDriver) Verify() error {
 		return err
 	}
 
+	if v := os.Getenv("DOCKER_HOST"); v != "" {
+		return fmt.Errorf(
+			"DOCKER_HOST cannot be set with the Packer Docker builder.")
+	}
+
 	return nil
 }