Java Traffic, limits and delivery
What sits between the user and your service, and how you protect it from more load than it can take.
3 concepts · 9 interview questions
What this topic covers
Every concept in traffic, limits and delivery, and the questions each one gets asked as. Where a question links, it has a full write-up.
Load balancing and routing
Spreading requests across instances, and deciding whether a user must keep reaching the same one.
- Which load balancing algorithm would you choose, and why?
- What is sticky session routing, and what does it cost you?
- Layer 4 or layer 7?
Rate limiting and backpressure
A limit protects a service from more work than it can do. Refusing early is a feature; queueing without a bound is how a system dies slowly.
- How would you implement a rate limiter?
- What is backpressure, and what happens without it?
- How do you rate limit fairly across tenants?
CDNs and static delivery
Serving bytes from close to the user, and never asking your origin for something that has not changed.
- What belongs on a CDN, and what must not?
- How do you deploy a change when the old file is cached everywhere?
- What do ETag and Cache-Control actually do?