Knative is a Kubernetes-based platform designed to facilitate the building and deployment of containerized serverless applications. It is an open-source project initiated by Google, and it provides middleware abstractions that are essential for source-to-URL deployments on Kubernetes, orchestrated by Istio or any other networking layer. This glossary entry will delve into the intricacies of Knative, its history, use cases, and specific examples of its application.
The term 'Knative' is derived from the word 'native', indicating its inherent compatibility with Kubernetes. It is designed to leverage the powerful features of Kubernetes, while simplifying the process of deploying and managing applications. Knative provides a set of middleware components that are essential for building modern, source-centric, and container-based applications that can run anywhere.
Definition and Explanation
Knative is a platform that enables developers to build, deploy, and manage serverless workloads on Kubernetes. It provides a set of middleware components that abstract away the complexities of building applications on Kubernetes, making it easier for developers to focus on writing code without worrying about the underlying infrastructure.
Serverless computing, also known as Function-as-a-Service (FaaS), allows developers to execute code in response to events without having to manage the underlying computing resources. Knative extends this concept to Kubernetes, providing a platform that allows developers to build serverless applications that can run on any Kubernetes cluster.
Components of Knative
Knative consists of three main components: Serving, Eventing, and Build. The Serving component is responsible for deploying and scaling serverless applications, the Eventing component handles the routing of events between different parts of an application, and the Build component is used to build and package applications from source code.
These components work together to provide a complete serverless platform on top of Kubernetes. They abstract away the complexities of Kubernetes, allowing developers to focus on writing code rather than managing infrastructure.
How Knative Works
Knative works by extending Kubernetes with custom resource definitions (CRDs). These CRDs define the building blocks for serverless applications, such as services, routes, and revisions. When a developer deploys a serverless application using Knative, these CRDs are used to configure the underlying Kubernetes resources.
For example, when a developer deploys a new version of an application, Knative creates a new revision. This revision is a snapshot of the application's code and configuration at a specific point in time. Knative then automatically manages the routing of traffic between different revisions, allowing for features like canary deployments and rollbacks.
History of Knative
Knative was first announced by Google in July 2018 as an open-source project. The goal of the project was to provide a set of common tooling that could be used to build, deploy, and manage serverless applications on Kubernetes. Since its initial release, Knative has been adopted by a number of companies and has seen significant growth in its community of contributors.
One of the key factors in Knative's success has been its focus on interoperability. From the beginning, the project has been designed to work with any Kubernetes cluster, regardless of the underlying infrastructure. This has made it a popular choice for companies looking to build serverless applications that can run anywhere.
Contributors and Community
Since its inception, Knative has attracted a diverse community of contributors. These contributors include both individuals and organizations, with major tech companies like Google, IBM, Red Hat, and Pivotal playing key roles in the project's development. This broad base of support has helped to drive the project's rapid growth and development.
The Knative community is also characterized by its openness and inclusivity. The project's governance model encourages participation from all members of the community, and decisions are made through a process of open discussion and consensus. This has helped to foster a vibrant and active community around the project.
Use Cases of Knative
Knative is used in a variety of scenarios, ranging from simple web applications to complex, multi-service architectures. Its flexible, modular design makes it a good fit for a wide range of use cases.
One common use case for Knative is the development of microservices. Microservices are small, independent services that work together to form a larger application. Knative's ability to automatically scale services up and down in response to demand makes it an ideal platform for deploying microservices.
Event-Driven Applications
Knative's Eventing component makes it a great fit for building event-driven applications. These are applications that respond to events, such as changes in a database or messages from a queue. Knative can route these events to the appropriate services, allowing developers to focus on writing the code that handles the events.
For example, a developer might use Knative to build a data processing pipeline. When new data arrives, it triggers an event that is routed to a service for processing. Once the data has been processed, it can trigger another event that is routed to a different service for storage or further processing.
Continuous Deployment
Knative's Build component can be used to implement continuous deployment pipelines. This allows developers to automatically build, test, and deploy their applications whenever they make changes to their code.
For example, a developer might set up a pipeline that automatically builds a new Docker image whenever they push changes to their Git repository. This image is then deployed to a staging environment for testing. If the tests pass, the image is automatically deployed to production.
Examples of Knative in Action
Several companies have shared their experiences using Knative in production. These examples provide a glimpse into how Knative can be used in real-world scenarios.
For instance, Pivotal has used Knative to build a serverless platform for their customers. They have found that Knative's modular design and focus on interoperability make it a good fit for their needs. They have also appreciated Knative's strong community and the rapid pace of its development.
Google Cloud Run
Google Cloud Run is a managed compute platform that enables you to run stateless containers that are invocable via web requests or Pub/Sub events. It is built from Knative, letting you choose to easily run your containers either fully managed with Cloud Run, or in your Google Kubernetes Engine cluster with Cloud Run for Anthos.
With Cloud Run, you are abstracted away from infrastructure management and can focus solely on your application logic. It's a great example of how Knative's principles and technology can be leveraged to provide a powerful and flexible serverless platform.
IBM Cloud Code Engine
IBM Cloud Code Engine is a fully managed, serverless platform that runs your containerized workloads, including web apps, microservices, event-driven functions, or batch jobs. Code Engine is built on top of open source Knative, therefore, it inherits all the advantages of Knative.
Code Engine simplifies the process of deploying your applications, whether they are developed from source code or packaged as a container image. It also automatically scales your applications based on demand, and you only pay for the resources that your applications consume.
Conclusion
Knative is a powerful platform for building and deploying serverless applications on Kubernetes. Its modular design, focus on interoperability, and strong community support make it a compelling choice for developers looking to leverage the power of Kubernetes without the complexity.
Whether you're building a simple web application or a complex, multi-service architecture, Knative provides the tools and abstractions you need to get the job done. With its growing community and rapid pace of development, Knative is poised to play a key role in the future of cloud computing.