Adds support for replicating from another Redis instance

Author: Alejandro Colomina

security_groups.tf

@@ -26,3 +26,13 @@ resource "aws_security_group_rule" "redis_networks_ingress" {
   cidr_blocks       = var.allowed_cidr
   security_group_id = aws_security_group.redis_security_group.id
 }
+
+resource "aws_security_group_rule" "redis_replication_egress" {
+  count             = var.is_migration_cluster ? 1 : 0
+  type              = "egress"
+  from_port         = 0
+  to_port           = 0
+  protocol          = "-1"
+  cidr_blocks       = ["0.0.0.0/0"]
+  security_group_id = aws_security_group.redis_security_group.id
+}

variables.tf

@@ -59,6 +59,12 @@ variable "redis_failover" {
   default = false
 }
 
+variable "is_migration_cluster" {
+  description = "Specifies whether this is a cluster for replicating other EC2 redis. Useful for migrations."
+  type = bool
+  default = false
+}
+
 variable "redis_node_type" {
   description = "Instance type to use for creating the Redis cache clusters"
   type        = string