Summary of "What is Serverless?"

Summary of technological concepts & key points (serverless + IBM Cloud framing)

The cloud provider abstracts away server management and provisioning.
Developers focus on writing code/business logic rather than operating infrastructure.

Bare metal: You manage OS installation, patching, environment setup—time-consuming.
Virtual machines: Improved resource use vs bare metal, but you still handle OS/environment and patching.
Containers (Docker): Package application code + dependencies into a container that can run across infrastructure.
- Easier deployment, but scaling/container management can become challenging.
- Still involves compute being “on” (some idle time).
Serverless (current focus): Greater abstraction from underlying infrastructure; primarily write business logic.

Most major cloud providers offer Functions as a Service (FaaS).
A function is a single unit of deployment (e.g., file processing).
Functions run in response to events (e.g., a user action like clicking submit triggers an event that invokes the function).

Serverless commonly uses an event-driven architecture:

A user uploads an image and submits → creates an event.
The event invokes a function to resize the image and store it in storage.
This illustrates event-to-function invocation and a typical serverless workflow.

Timeouts: Functions are stateless, spin up briefly, and are deleted after execution; if work doesn’t finish in time, the app fails.
Latency: Can be an issue depending on how time-sensitive the application is.

Pay for execution only: No cost for idle capacity; functions are often described as running on the order of ~100 ms.
Auto-scaling by the provider: Less need to provision resources yourself.
Faster time to market: Reduced infrastructure management speeds development.
Polyglot support: Ability to use multiple languages/frameworks supported by the platform.
High availability: Provider handles fault tolerance and multi–zone regions (MZRs); event-driven services are also fault tolerant, aiming for overall high availability.