Question

which configuration setting allows you set a hard upper bound on the amount of memory that is available to a running redis instance.

Answer 1

In order to allow a hard upper bound on amount of memory that is available, we need to understand the redis by itself. Redis configuration can run without any configuration by using in-built functions. The correct way of configuring Redis is to configure a Redis configuration file  usually called redis.conf.

Answer 2

maxmemory configuration setting allows you set a hard upper bound on the amount of memory that is available to a running Redis instance.