Phone Screen
Initial screening questions covering basic technical concepts
In CIDR notation, what does a /24 signify and roughly how many usable IPv4 addresses are in such a subnet?
Explain the key differences between Docker containers and virtual machines. When would you use one over the other?
What is the difference between Continuous Integration, Continuous Delivery, and Continuous Deployment?
Explain the difference between git merge and git rebase. When would you use one over the other?
Explain the meaning of HTTP status codes 200, 301, 403, 404, and 500.
A pod is stuck in Pending state. What are the common causes and troubleshooting steps?
What are the key differences between TCP and UDP, and when would you use one over the other?
Explain the difference between Layer 4 and Layer 7 load balancing. Provide examples of when each would be used.
Walk me through the steps when you type a URL into your browser and press enter.
Explain the differences between IaaS, PaaS, and SaaS, and provide one example of each.
Which Linux command quickly shows disk usage for all mounted filesystems in a human-readable format?
What is the difference between SSL and TLS, and why is TLS preferred today?
What is a fast-forward merge in Git, and when would you use --no-ff?
Why are SSH key pairs generally preferred over passwords for server access?
How do you quickly identify which processes are consuming the most CPU on a Linux server?
What is the difference between ping and traceroute, and when would you use each?
What is HTTP keep-alive and why does connection pooling improve performance?
What is the difference between a Docker image and a Docker container?
Briefly explain ClusterIP, NodePort, and LoadBalancer service types in Kubernetes and when to use each.
What are best practices for managing secrets (API keys, tokens) in CI/CD pipelines?
What is Terraform state and why is it important to store it remotely?
What does the cron expression "0 2 * * 1-5" mean, and how would you test a cron job locally?
When would you use git stash instead of committing to a new branch, and what are the trade-offs?
What is the difference between an annotated tag and a lightweight tag in Git, and when would you choose each?
What is the difference between a subnet and a VLAN, and how do they relate in typical architectures?
A server reports high memory usage. What quick checks do you perform to identify the cause?
Explain the meaning of rwx for user, group, and others, and how chmod/chown modify permissions.
Which command would you use to find the largest files/directories consuming disk space in a path?
What is the cloud shared responsibility model and how do responsibilities differ between IaaS and SaaS?
What are Docker multi-stage builds and why are they useful?
What is the difference between a ConfigMap and a Secret in Kubernetes, and when do you use each?
Which HTTP methods are idempotent and why does idempotency matter in API design?
What is the difference between NAT and PAT, and where would you use each?
Briefly describe the TLS handshake steps and how the client verifies the server.
What does a shallow clone do in Git and when is it useful?
Name two key improvements HTTP/2 brings over HTTP/1.1 and why they matter.
What is the difference between readiness and liveness probes in Kubernetes?
What does the shebang line do in a script, and what permission is required to run it directly?
How do you check, start, and enable a service with systemd, and where are unit files located?
What do the 1, 5, and 15 minute load averages indicate on Linux, and how do you interpret them relative to CPU cores?
What problem does a CDN solve and how does it improve user-perceived performance?
What is the difference between an A record and a CNAME record in DNS, and when would you use each?
What is API rate limiting, why is it important, and how is it commonly implemented?
What is the difference between a Docker volume and a bind mount, and when would you use each?
Compare OAuth2 and SAML for authentication and authorization scenarios.
What is the difference between Kubernetes Ingress and Service, and when would you use each?
Name two popular load testing tools and explain their typical use cases.
What are the key differences between AWS, Azure, and GCP offerings at a high level?
Name two commonly used log aggregation tools and briefly explain their benefits.
What is distributed tracing, and why is it important in microservices architectures?
Briefly explain the main phases of an incident response process.
What is DNS propagation, and why can DNS record changes take time to be visible globally?