Cache/Config and Message Infrastructure

So, as I add on infrastructure I think I'm going with the following pieces, they should be deployed in a high-availability cluster configuration.

• Configuration information - ETCD
• Possible secrets storage - via Crypt, or possibly Vault
• Caching - Redis
• Messaging, Events and Subscriptions - AMQP via RabbitMQ

EtcD and Redis really do have different purposes and so it actually makes sense to have both.   I've used Redis, so I know it, as opposed to MemCacheD.  Etcd actually used gRPC internally so it kind of makes sense too.

I do need a place to store passphrases and keys.   This will likely go in EtcD, though encrypted themselves.  I'm not that fond of Vault, but I haven't used it in a long time -- I used an early version.  Once I get the PKI infrastructure working, I need to put it somewhere.