Arpit's Newsletter read by 70000+ engineers
Weekly essays on real-world system design, distributed systems, or a deep dive into some super-clever algorithm.
Introduction to Serverless Computing and Architecture
Serverless is a cost-efficient way to host your APIs and it forms the crux of systems like Chatbots and Online Judge.
Serverless does not mean that your code will not run on the server; it means that you do not manage, maintain, access, or scale the server your code is running on.
The traditional way to host APIs is by spinning up a server with some RAM, and CPU. Say the resources make your server handle 1000 RPS, but you are getting 1000 RPS only 1% of the time which means for the other 99% you are overprovisioned.
So, what if there was an Infrastructure that
- scales up and down as per the traffic
- is billed per execution
- is self-managed maintained and fault-tolerant
These requirements gave rise to Serverless Computing.
Real-world applications
Chatbot
Say, we build a Slack chatbot that responds with the Holiday list when someone messages holidays . The traffic for this utility is going to be insignificant, and keeping a server running the whole time is a waste. This is best modeled on Serverless which is invoked on receiving a message.
Online Judge
Every submission can be evaluated on a serverless function and results can be updated in a database. Serverless gives you isolation out of the box and keeps the cost to a bare minimum. It would also seamlessly handle the surge in submissions.
Vending Machine
Upon purchase, the Vending machine would need to update the main database, and the APIs for that could be hosted on Serverless. Given the traffic is low and bursty, Serverless would help us keep the cost down.
Scheduled DB Backups
Schedule daily DB backups on the Serverless function instead of running a separate crontab server just to trigger the backup.
Batch and Stream Processing
Use serverless and invoke the function every time a message is pushed on the broker making the system reactive instead of poll-based.
Advantages
- No need to manage and scale the infra
- The cost is 0 when you do not get any traffic
- Scale is out of the box; so no capacity planning is needed
Disadvantages
- Takes time to serve the first request as the underlying infra might boot up
- The execution has a max timeout, so your job should complete within the limit
- Debugging is a challenge
- You are locked in on the vendor you chose
When NOT to use Serverless
- Load, usage, and traffic pattern is consistent
- Execution will go beyond the max timeout
- You need multi-tenancy
When to use Serverless
- Quick build, prototype, and deploy the changes
- Usecase is lightweight
- Traffic is bursty
Here's the video ⤵
Courses
Super practical courses, with a no-nonsense approach, are designed to spark engineering curiosity and help you ace your career.
System Design for Beginners
An in-depth, self-paced, and on-demand course that for early engineers to become great at designing scalable, available, and extensible systems at scale.
System Design Masterclass
A masterclass that helps experienced engineers become great at designing scalable, fault-tolerant, and highly available systems.
Redis Internals
A course that helps covers Redis internals by reimplementing its core features like - event loop, serialization protocol, pipelining, eviction, and transactions.