Kubernetes sem servidor (Knative)
Explore como plataformas como o Knative possibilitam funções sem servidor e arquiteturas orientadas a eventos sobre o Kubernetes.
Kubernetes sem servidor (Knative) é uma aula grátis de Docker & Kubernetes for Developers no CoddyKit. Esta é a aula 3 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de Docker & Kubernetes for Developers, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de Docker & Kubernetes for Developers inclui 4 aulas no total.
Partes desta aula ainda não foram traduzidas e aparecem em inglês.
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.
Perguntas Frequentes
A aula “Kubernetes sem servidor (Knative)” é grátis?
Sim — o texto completo de “Kubernetes sem servidor (Knative)” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de Docker & Kubernetes for Developers, atualize para CoddyKit PRO. O curso de Docker & Kubernetes for Developers inclui 4 aulas no total.
O que vou aprender em “Kubernetes sem servidor (Knative)”?
Explore como plataformas como o Knative possibilitam funções sem servidor e arquiteturas orientadas a eventos sobre o Kubernetes. Você pratica Docker & Kubernetes for Developers com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.
Preciso ter experiência prévia para começar Docker & Kubernetes for Developers?
Nenhuma experiência prévia é necessária. Docker & Kubernetes for Developers no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 3 de 4.
Quanto tempo leva a aula “Kubernetes sem servidor (Knative)”?
A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.
Posso escrever e executar código nesta aula de Docker & Kubernetes for Developers?
Sim. Cada aula de Docker & Kubernetes for Developers inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.
Todas as aulas deste curso
- Definições de recursos personalizados (CRDs)
- O padrão Operator no Kubernetes
- Kubernetes sem servidor (Knative)
- Estendendo o servidor da API com webhooks de admissão