I am fairly certain that RedisCloud (which may be a part of RedisLabs) offers Redis clusters abstracted by the connection URL.
@barsrki I was not aware that RedisCloud provided a clustered cloud solution. Thanks for the note, I will add an update to the article shortly to reflect that.
When your Redis instance is down, so is ActionCable. Clustering is of course an option, however as far as I am aware, there are currently no commercial Redis cluster database-as-a-service offerings.