“Teach Ansible to talk to Github on your behalf” enables all your servers to establish arbitrary SSH connections using the private key(s) in your agent. That’s pretty terrible unless you explicitly and consciously decide to have zero isolation between your hosts. Similarly for storing all secrets in one file: you’re sharing all the secrets with all the hosts.
If the author does think that’s fine, then I think the article should at least clearly state the implications, as certainly not everyone agrees. I, for example, manage a bunch of servers with ansible where maybe a dozen people have root access. I don’t want those people to be able to SSH anywhere with my keys.
As for “Add Github to known_hosts properly and securely”, doing the keyscan on your laptop does nothing to prevent MITM attacks, not on first use nor on subsequent executions of the task. It will just write whatever ssh-keyscan returns this time into the known_hosts. The bit about having to write another play for updating seems wrong to me.
Since talking to Github via ssh would blow up badly if Github ever changed their hostkey, I think hardcoding it is a fine solution. (If we ignore the general inadequatenes of transport security for authenticating code you’re about to execute, but that’s a different discussion.)
I agree with this. I thought the points were overall pretty good, especially the variable handling, vagrant setup, and error handling. All points I came to through some hard experience. I don’t think a lot of this is easy to understand when getting started and I like to see articles like this.
But the SSH connections are pretty important and it involves the security engineering of the application architecture. I do some not-great-things as well but they are all an element of the politics behind the infrastructure rather than designing a secure system. Telling the difference is not obvious.
I’d take the points of SSH with a grain of salt and not architect like this unless you are sure it has to be done. I understand it is a trade-off. A good self-test is to name the trade-offs and discuss it with you team.