Knative is a Kubernetes-based platform designed to provide a set of middleware components that are essential for building modern, source-centric, and container-based applications that can run anywhere. Developed by Google, it simplifies the complex process of building, deploying, and managing applications on Kubernetes, making it an integral part of the containerization and orchestration ecosystem.
Containerization is a lightweight alternative to full machine virtualization that involves encapsulating an application in a container with its own operating environment. This provides many of the benefits of load isolation and security but with far less overhead. Orchestration, on the other hand, refers to the automated configuration, coordination, and management of computer systems, services, and applications. In the context of containers, orchestration is about managing the lifecycles of containers, especially in large, dynamic environments.
Definition of Knative
Knative (pronounced ‘kay-nay-tiv’) is an open-source platform based on Kubernetes that provides a set of middleware components for building, deploying, and managing modern serverless workloads. It is designed to hide the complexity of building apps on Kubernetes and to provide the benefits of serverless computing with the flexibility of a Kubernetes environment.
The platform consists of three main components: Build, Serving, and Eventing. Build is responsible for the source-to-container build processes; Serving manages the networking, autoscaling, and rollouts; and Eventing handles the delivery of events. Together, these components provide a comprehensive solution for running applications on Kubernetes.
Understanding Knative Components
The Build component of Knative is designed to take source code and create a container from it. This process is defined using a series of steps, each of which is a container. The output of one step is the input to the next. This component is designed to be pluggable, so it can be replaced with other build systems like Jenkins, Tekton, etc.
The Serving component is responsible for managing the lifecycle of applications, from deployment to scaling to routing. It supports automatic scaling, including scaling to zero when no requests are being served. It also supports rapid deployment and rollback, and it provides a clean abstraction for dealing with network programming, sharing the network programming load with the Istio service mesh.
The Eventing component is designed to provide composable primitives to connect applications with events. It provides a common mechanism for handling and delivering events from various sources and with various types of service.
History of Knative
Knative was first announced by Google in July 2018 as a Kubernetes-based platform to build, deploy, and manage modern serverless workloads. It was developed in collaboration with Pivotal, IBM, Red Hat, and SAP. The goal was to provide developers with the ability to use familiar tools and processes to deploy and manage applications, without the need to learn the intricacies of Kubernetes.
Since its initial release, Knative has gained significant traction in the cloud-native community and has become a key component in many Kubernetes-based platforms. It has also evolved significantly, with improvements to its core components and the addition of new features.
Key Milestones in Knative's History
The first major milestone in Knative's history was its initial release in July 2018. This release included the three core components: Build, Serving, and Eventing. It also included a set of sample applications and a developer guide to help users get started.
In November 2018, Google announced that Knative would be the basis for its new Google Cloud Run service, which provides a fully managed environment for deploying and scaling containerized applications quickly and securely. This announcement helped to further increase Knative's visibility and adoption.
In 2019, the Knative team decided to deprecate the Build component in favor of Tekton, a more powerful and flexible open-source framework for creating CI/CD systems. This decision was made to avoid duplication of effort and to focus on improving the Serving and Eventing components.
Use Cases of Knative
Knative is designed to be a general-purpose platform for running applications on Kubernetes, but it is particularly well-suited for certain types of workloads. These include event-driven applications, real-time data processing, and machine learning workloads.
Event-driven applications can benefit from Knative's Eventing component, which provides a common mechanism for handling and delivering events. This can simplify the process of building applications that respond to events from various sources.
Real-time data processing workloads can benefit from Knative's automatic scaling capabilities, which can scale applications up and down based on demand. This can be particularly useful for workloads that have variable demand, such as those that process data in real-time.
Machine learning workloads can benefit from Knative's ability to run complex workflows and manage the lifecycle of applications. This can simplify the process of deploying and managing machine learning models, and it can make it easier to scale these workloads as needed.
Examples of Knative in Action
One example of Knative in action is its use in Google Cloud Run. Cloud Run is a fully managed compute platform that automatically scales stateless containers. By using Knative, Cloud Run is able to provide developers with a simple, flexible, and secure way to run their applications.
Another example is IBM's use of Knative in its IBM Cloud Kubernetes Service. This service provides a fully managed Kubernetes environment on the IBM Cloud. By using Knative, IBM is able to provide its customers with a powerful, flexible, and easy-to-use platform for running their applications.
A third example is Pivotal's use of Knative in its Pivotal Function Service. This service provides a Kubernetes-based platform for running functions. By using Knative, Pivotal is able to provide a platform that is easy to use, flexible, and powerful.
Conclusion
Knative is a powerful platform for building, deploying, and managing applications on Kubernetes. It provides a set of middleware components that simplify the process of running applications on Kubernetes, making it an integral part of the containerization and orchestration ecosystem.
Whether you're a developer looking to build event-driven applications, a data scientist looking to deploy machine learning models, or an operator looking to manage applications at scale, Knative has something to offer. With its focus on simplicity, flexibility, and power, it's no wonder that Knative is quickly becoming a key component in many Kubernetes-based platforms.