OpenFaaS

OpenFaaS is an open-source framework for building and running functions on top of Kubernetes and related container-based platforms.

Website:

• openfaas.com
• OpenFaaS docs

Information

OpenFaaS gives teams a practical way to run functions while still using familiar container and Kubernetes operations. It is often used when a team wants serverless-style packaging and scaling without giving up cluster-level control.

Main functionalities and features

• Function packaging: create functions from templates and container images,
• Gateway model: route requests and manage deployments through the gateway,
• Autoscaling: scale functions based on demand,
• Queue-based async execution: support asynchronous invocation patterns,
• Template ecosystem: accelerate adoption across several runtimes,
• Kubernetes integration: good fit for teams already operating clusters.

Core building blocks

Gateway

The gateway is the main entry point for deployment and invocation workflows.

Functions

Functions are usually packaged as container images and deployed with metadata such as environment variables, secrets, and scaling behavior.

Templates

Templates help standardize how functions are written and built in different languages.

Async and queue workers

OpenFaaS supports queue-based patterns so workloads do not need to be handled only as direct synchronous requests.

When it can be useful

OpenFaaS is useful when:

• the team already uses Kubernetes,
• you want practical serverless patterns in your own cluster,
• functions should be deployed like containers,
• synchronous and asynchronous execution are both important,
• developers want a straightforward path from code to function image.

Typical use cases:

• webhook handlers,
• lightweight API backends,
• file or image processing,
• asynchronous background jobs,
• automation around internal tools.

Getting started

A practical adoption path usually looks like this:

1. start with one low-risk function,
2. install OpenFaaS in a development cluster,
3. pick a function template and deploy a simple HTTP function,
4. validate logging, secrets, and scaling behavior,
5. test one asynchronous use case before wider rollout.

Useful evaluation questions:

• whether all target workloads fit the function model,
• how secrets and configuration are handled,
• whether cold starts are acceptable,
• how much traffic variability must be absorbed,
• how the gateway is exposed and secured,
• what build pipeline should produce and scan function images.

Tips and tricks

• Use OpenFaaS for small, well-bounded functions instead of replacing every service with functions.
• Treat images, templates, and secrets as part of the platform contract.
• Measure scaling and startup time under realistic load.
• Keep observability in place from day one: request rate, latency, failures, queue depth, and function execution time.
• If the cluster hosts many workloads, define resource limits carefully so bursty functions do not starve other services.

Things to watch

• Function platforms still require operational ownership.
• Not every workload benefits from serverless packaging.
• Queue-based execution needs explicit retry and idempotency design.
• Teams should avoid mixing too many deployment styles without clear standards.
• Security of the gateway, function images, and secret handling must be reviewed carefully.

Where it fits best

OpenFaaS fits best for:

• Kubernetes-oriented teams,
• internal serverless platforms,
• function-style automation,
• event and webhook processing,
• teams that prefer open tooling over fully managed cloud-only function services.

See also

• Kubernetes
• Knative
• Apache OpenWhisk
• Terraform
• OpenFaaS