Merge pull request terraform-community-modules#26 from Testinos/redis_upgrade_engine

fix Parameter Groups removing in update engine

Author: antonbabenko

main.tf

@@ -1,7 +1,9 @@
 data "aws_vpc" "vpc" {
   id = "${var.vpc_id}"
 }
-
+resource "random_id" "salt" {
+  byte_length = 8
+}
 resource "aws_elasticache_replication_group" "redis" {
   replication_group_id          = "${format("%.20s","${var.name}-${var.env}")}"
   replication_group_description = "Terraform-managed ElastiCache replication group for ${var.name}-${var.env}-${data.aws_vpc.vpc.tags["Name"]}"
@@ -21,12 +23,15 @@ resource "aws_elasticache_replication_group" "redis" {
 }
 
 resource "aws_elasticache_parameter_group" "redis_parameter_group" {
-  name        = "${replace(format("%.255s", lower(replace("tf-redis-${var.name}-${var.env}-${data.aws_vpc.vpc.tags["Name"]}", "_", "-"))), "/\\s/", "-")}"
+  name        = "${replace(format("%.255s", lower(replace("tf-redis-${var.name}-${var.env}-${data.aws_vpc.vpc.tags["Name"]}-${random_id.salt.hex}", "_", "-"))), "/\\s/", "-")}"
   description = "Terraform-managed ElastiCache parameter group for ${var.name}-${var.env}-${data.aws_vpc.vpc.tags["Name"]}"
 
   # Strip the patch version from redis_version var
   family    = "redis${replace(var.redis_version, "/\\.[\\d]+$/","")}"
   parameter = "${var.redis_parameters}"
+  lifecycle {
+   create_before_destroy = true
+ }
 }
 
 resource "aws_elasticache_subnet_group" "redis_subnet_group" {