Questions were wide ranging in terms of Platform Engineering covering all the kinds of topics you'd expect:
1) DNS - you open up a browser, you type in www.google.co.uk, what is happening?
2) TLS/SSL - you open up a browser, you type in www.amazon.co.uk, you see a padlock next to the URL, what does this mean? - describe the process and what's going on in the background. Various questions pointing towards handshakes, key exchange, encryption/decryption etc.
3) Lots of questions on AWS, load balancing, EC2, Kubernetes/EKS, security groups, NACLs (google AWS interview questions and you'll find the ones they were using)
4) Git - explain how to make a change to an environment (cloning of repos, adding new files/changes, committing them, pushing back to the repo, when to do a git merge vs a git rebase, what the difference is between the two.
5) Various questions on Kubernetes using kubectl (again, google search interview questions on kubernetes and you'll find the ones being asked)
6) Docker containers - explain what an image is, how you'd build one, what a dockerfile looks like
7) Terraform/IaC - explain backends, what a state file is, when would you use remote state files and why, when would you use secrets, when would you use a module, what does the standard lifecycle look like (i.e. plan/apply/destroy/refresh
8) CI/CD - what is the difference between the two, what does a standard pipeline look like.
