Interview Notes

Linux

• what is the difference between a process and a thread
• what does systemd do
• how to investigate an OOM condition
• the difference between a hard link and a soft link
• why ss is usually better than netstat on modern systems

Networking

• the difference between TCP and UDP
• what subnet mask or CIDR means
• how DNS resolution works
• what a default gateway does
• the difference between timeout and connection refused

Docker

• the difference between an image and a container
• why volumes exist
• how docker compose differs from a Dockerfile
• how to view logs and enter a container

Kubernetes

• the difference between Pod, Deployment, and StatefulSet
• how a Service delivers traffic to Pods
• how ConfigMap differs from Secret
• what to check when a Pod is in CrashLoopBackOff

Ansible

• what idempotency means
• when to use a module and when to use shell
• how inventory, roles, and group vars are structured
• how to store secrets

Terraform

• why state is needed
• how a resource differs from a data source
• what happens if a resource is deleted manually in the cloud
• why a remote backend and locking matter

What Is Useful to Answer Confidently

• not only the definition, but also a practical example
• which commands you actually use for troubleshooting
• what tradeoffs the tool has