Serverless con Kubernetes (Knative)
Esplori come piattaforme come Knative abilitino funzioni serverless e architetture event-driven basate su Kubernetes.
Serverless con Kubernetes (Knative) è una lezione Docker & Kubernetes for Developers gratuita su CoddyKit. Questa è la lezione 3 di 4. Puoi leggere la lezione completa qui gratuitamente — poi esercitati direttamente nel browser con un editor di codice integrato e un tutor IA disponibile 24/7. Fa parte del percorso di apprendimento Docker & Kubernetes for Developers, e i tuoi progressi si sincronizzano tra il web e l'app CoddyKit. Il corso Docker & Kubernetes for Developers include 4 lezioni in totale.
Parti di questa lezione non sono ancora state tradotte e vengono mostrate in inglese.
Serverless & Kubernetes
Welcome to the world of serverless on Kubernetes! Serverless computing allows you to run code without provisioning or managing servers, focusing purely on your application logic.
By combining serverless with Kubernetes, you get the benefits of both: the agility and cost-efficiency of serverless, backed by the robust, scalable, and portable infrastructure management of Kubernetes.
Knative: K8s Serverless
Knative is an open-source platform that extends Kubernetes to provide components for deploying, running, and managing serverless workloads. It simplifies the complexities of running serverless applications.
Knative has two main components: Knative Serving, which handles request-driven services, and Knative Eventing, for event-driven architectures.
Knative Serving Basics
Knative Serving is designed for deploying and managing stateless services. It takes care of:
- Rapid Deployment: Quickly deploys container images.
- Auto-scaling: Scales services up and down based on demand, even to zero instances when idle.
- Revision Management: Provides immutable revisions for easy rollbacks and traffic splitting.
It's perfect for web applications, APIs, and microservices.
Serving: Services & Revisions
Key concepts in Knative Serving:
- Service: The top-level resource, defining the desired state of your application.
- Revision: An immutable snapshot of your service's code and configuration at a specific point in time. New deployments create new revisions.
- Route: Manages network traffic to one or more revisions, enabling features like A/B testing or gradual rollouts.
These components work together to provide a robust deployment and scaling mechanism.
Defining a Knative Service
A Knative Service is defined using a YAML manifest, much like other Kubernetes resources. This example defines a simple 'hello-knative' service using a pre-built image.
Notice the serving.knative.dev/v1 API version and the kind: Service.
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: hello-knative
spec:
template:
spec:
containers:
- image: docker.io/knative/helloworld-go
env:
- name: TARGET
value: "Knative"Simple Serverless App
This is a basic Python Flask application that Knative would deploy. It listens for HTTP requests and responds with a greeting, using an environment variable for customization. Knative handles the containerization, deployment, and scaling of this app.
from flask import Flask
import os
app = Flask(__name__)
@app.route('/')
def hello():
target = os.environ.get('TARGET', 'World')
return f'Hello {target}!\n'
if __name__ == '__main__':
app.run(host='0.0.0.0', port=8080)Knative Eventing
Knative Eventing enables event-driven architectures on Kubernetes. It allows services to communicate asynchronously by sending and receiving events, decoupling the event producers from consumers.
This is crucial for building reactive systems that respond to various changes, like data updates, file uploads, or scheduled tasks.
Eventing: Sources & Brokers
Key components in Knative Eventing:
- Event Source: Generates events from various systems (e.g., Kafka, GitHub, CronJob, S3).
- Broker: A central messaging hub where event sources send events. It abstracts the underlying messaging system.
- Trigger: Filters events from a Broker based on attributes and routes them to a specific event consumer (often a Knative Service).
This flow enables flexible and scalable event processing.
Example Event Flow
Imagine you have a service that processes new images. You can set up an Event Source that monitors an S3 bucket for new image uploads.
When an image is uploaded, the source sends an event to a Broker. A Trigger, configured to filter for 'new S3 image' events, then forwards that event to your image processing Knative Service.
Your service processes the image, scales down when idle, and you only pay for the compute used during processing.
Knative Knowledge Check
Which Knative component is primarily responsible for automatically scaling services up or down based on incoming requests, including scaling to zero when idle?
Knative Recap
In this lesson, you explored how Knative brings serverless capabilities to Kubernetes. You learned about:
- Knative Serving: For deploying and auto-scaling request-driven services.
- Knative Eventing: For building event-driven architectures with sources, brokers, and triggers.
Knative empowers developers to build and run serverless applications with the control and flexibility of Kubernetes.
Domande Frequenti
La lezione «Serverless con Kubernetes (Knative)» è gratuita?
Sì — il testo completo di «Serverless con Kubernetes (Knative)» è gratuito qui sul web. Per esercitarvi in modo interattivo (un editor di codice integrato e un tutor IA 24/7) e sbloccare il resto del corso Docker & Kubernetes for Developers, passa a CoddyKit PRO. Il corso Docker & Kubernetes for Developers include 4 lezioni in totale.
Cosa imparerò in «Serverless con Kubernetes (Knative)»?
Esplori come piattaforme come Knative abilitino funzioni serverless e architetture event-driven basate su Kubernetes. Eserciti Docker & Kubernetes for Developers con codice pratico che esegui direttamente nel browser, e un tutor IA 24/7 risponde alle tue domande mentre lavori sulla lezione.
Ho bisogno di esperienza per iniziare Docker & Kubernetes for Developers?
Non è richiesta alcuna esperienza precedente. Docker & Kubernetes for Developers su CoddyKit è strutturato per principianti e studenti avanzati, quindi puoi iniziare da qui o dall'inizio e procedere al tuo ritmo. Questa è la lezione 3 di 4.
Quanto tempo richiede la lezione «Serverless con Kubernetes (Knative)»?
La maggior parte delle lezioni CoddyKit richiede circa 5–10 minuti. Ogni lezione è breve e interattiva, quindi fai progressi costanti e riprendi esattamente da dove hai lasciato su web e app.
Posso scrivere ed eseguire codice in questa lezione Docker & Kubernetes for Developers?
Sì. Ogni lezione Docker & Kubernetes for Developers include un editor di codice integrato, quindi scrivi ed esegui codice reale direttamente nel tuo browser e ricevi feedback istantaneo dall'IA — nessuna configurazione locale necessaria.
Tutte le lezioni di questo corso
- Custom Resource Definition (CRD)
- Il pattern Operator in Kubernetes
- Serverless con Kubernetes (Knative)
- Estendere l'API server con gli admission webhook