Solutions for a secure distributed cache

Question

Problem: I want to cache user information such that all my applications can read the data quickly, but I want only one specific application to be able to write to this cache.

I am on AWS, so one solution that occurred to me was a version of memcached with two ports: one port that accepts read commands only and one that accepts reads and writes. I could then use security groups to control access.

Since I'm on AWS, if there are solutions that use out-of-the box memcached or redis, that'd be great.

Answer 1

I suggest you use ElastiCache with one open port at 11211(Memcached)then create an EC2 instance, set your security group so only this server can access to your ElastiCache cluster. Use this server to filter your applications, so only one specific application can write to it. You control the access with security group, script or iptable. If you are not using VPC, then you can use cache security group.

Answer 2

I believe you can accomplish this using Redis (instead of Memcached) which is also available via ElastiCache. Once the instance has been created, you will want to create a replication group and associate it to the cache cluster you already launched.

You can then add instances to the replication group. Instances within the replication group are simply replicated from the Master Cache Cluster (single Redis instance) and so are (by default) read-only.

So, in this setup, you have a master node (single endpoint) that you can write to and as many read nodes (multiple endpoints) as you would like.

You can take security a step further and assign different routing rules to the replication group (via the VPC) so the applications reading data does not have access to the master node (the only one that can write data).