How to configure multiple deploy keys for different private github repositories on the same computer without using ssh-agent

Let's say alice is a github.com user, with 2 or more private repositories repoN. For this example we'll work with just two repositories named repo1 and repo2

https://github.com/alice/repo1

https://github.com/alice/repo2

You need to be to pull from these repositories without entering a passwords probably on a server, or on multiple servers.