From e9c4d4f6d56a0276ad797f46117a0ff427f78e65 Mon Sep 17 00:00:00 2001
From: Paul Hinze <phinze@phinze.com>
Date: Thu, 10 Mar 2016 14:51:30 -0600
Subject: [PATCH] Revert "provider/aws: Support additional changes to security
 groups of instance without forcing new"

---
 .../providers/aws/resource_aws_instance.go    | 23 +------------------
 1 file changed, 1 insertion(+), 22 deletions(-)

diff --git a/builtin/providers/aws/resource_aws_instance.go b/builtin/providers/aws/resource_aws_instance.go
index 6ff22572f..bacf975aa 100644
--- a/builtin/providers/aws/resource_aws_instance.go
+++ b/builtin/providers/aws/resource_aws_instance.go
@@ -107,6 +107,7 @@ func resourceAwsInstance() *schema.Resource {
 				Type:     schema.TypeSet,
 				Optional: true,
 				Computed: true,
+				ForceNew: true,
 				Elem:     &schema.Schema{Type: schema.TypeString},
 				Set:      schema.HashString,
 			},
@@ -580,28 +581,6 @@ func resourceAwsInstanceUpdate(d *schema.ResourceData, meta interface{}) error {
 		}
 	}
 
-	if d.HasChange("security_groups") {
-		var groupIds []*string
-		if v := d.Get("security_groups").(*schema.Set); v.Len() > 0 {
-			resp, err := conn.DescribeSecurityGroups(&ec2.DescribeSecurityGroupsInput{
-				GroupNames: expandStringList(v.List()),
-			})
-			if err != nil {
-				return err
-			}
-			for _, v := range resp.SecurityGroups {
-				groupIds = append(groupIds, aws.String(*v.GroupId))
-			}
-		}
-		_, err := conn.ModifyInstanceAttribute(&ec2.ModifyInstanceAttributeInput{
-			InstanceId: aws.String(d.Id()),
-			Groups:     groupIds,
-		})
-		if err != nil {
-			return err
-		}
-	}
-
 	if d.HasChange("vpc_security_group_ids") {
 		var groups []*string
 		if v := d.Get("vpc_security_group_ids").(*schema.Set); v.Len() > 0 {