Explain Redis/MySQL internals and containers vs VMs
Company: eBay
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: medium
Interview Round: Onsite
Answer the following backend fundamentals questions clearly and succinctly:
1. **Redis internals**
- What is Redis’s high-level architecture?
- What “engine” does Redis use to process requests?
- How do persistence and replication work at a high level?
2. **MySQL internals**
- What are MySQL storage engines (e.g., InnoDB)?
- How does the storage engine relate to indexes, transactions, and logging?
- What are key differences between common engines?
3. **Docker and Kubernetes**
- What is Docker (conceptually and in terms of runtime components)?
- What is Kubernetes, and what problems does it solve?
- What are the key differences between **Docker containers** and **virtual machines**?
Quick Answer: This question evaluates understanding of backend system internals and operational tooling—specifically in-memory datastore architecture (Redis), relational storage engine behavior (MySQL), and container orchestration and virtualization concepts (Docker, Kubernetes, and containers versus virtual machines).