Trouble connecting to host by aliased hostname

I've been running into trouble trying to open a connection from one docker container to another. I've set up redis to run from the base docker alpine image with minimal configuration. I've also set up an nginx server to make some calls out to the redis container. I've found that I can open and establish a connection using redis-lua and calling redis.connect(""). I can also put the redis-server package and connect using redis-cli -h and ping the server as well. But when I try to open a connection using lua-resty-redis, I keep getting connection refused:

connection refused, client: 192.168.21.252, server:
I'm unsure if this is a DNS issue, as it appears that there is no server. But I would expect if this was the case, then the redis-lua library and the redis-cli would not work as well. Any idea what is going on here?

Start by reproducing the Docker Alpine setup described, with nginx connecting through lua-resty-redis to Redis. Compare that connection with redis-lua and redis-cli using the aliased hostname; done means identifying why only lua-resty-redis is refused and documenting a verified resolution.