Serverless frameworks are in demand for the last few years and have been witnessing increased adoption among developers.
Nevertheless, container-based applications are already popular, and so are Kubernetes among businesses.
Kubernetes, without a doubt, is a great tool having good potential. Its ecosystem is also growing with a variety of new tools and the latest technologies, such as Knative, which has the power to make Kubernetes even better.
Knative was introduced to overcome situations that lead to failure and establish a core standard for cloud platforms and cloud-native orchestration.
In other words, the Knative serverless framework can fit a company’s needs way better than other cloud-based serverless deployments.
In this guide, I’ll talk about Knative, its benefits, use cases, installation procedure, working procedure, and more.
Here we go!
What Is Knative?
Knative is a Kubernetes-based serverless framework that was first developed by Google. It loads and runs serverless functions based on a company’s requirements, thereby minimizing waste. It’s an open-source project that adds components to deploy, run, and manage serverless applications on Kubernetes.
The primary purpose of the Knative serverless framework is to manage the standards for cross-platform orchestration. This is implemented by integrating the function of container creation, auto-scaling, event models, and workload management.
Earlier, there were a variety of open-source solutions other than Knative. Each solution has its way of deployment, which can cause market fragmentation since there is a lack of standardized practices. This means choosing a specific provider is necessary if you want a particular system feature.
However, migration problems started coming to the front. And to avoid such problems, the Knative serverless framework was introduced. So, if you struggle to incorporate any tasks, Knative can efficiently do it within the Kubernetes-based pipeline.
Knative has three pieces:
- Knative Build: It builds container images and makes them available from the source code.
- Knative Serving: It uses Istio and Kubernetes to connect and deploy these container images through the assigned infrastructure resources.
- Knative Eventing: It allows users to define the event triggers and lets users associate the event triggers with containerized functions.
Whenever Knative identifies an event, it defines the associated process to run it on demand. With Knative, there is no need to allocate container nodes, clusters, and pods for work since Knative commits hosting resources only when a given process runs. This way, Knative balances serverless and container benefits.
Core Concepts of Knative
Let’s discuss the Knative Serverless Framework’s main concepts and how they pertain to the Knative primitives.
Knative-building helps utilize and extend the existing Kubernetes’ primitives, allowing you to run on container builds from the origin. It enables the source code from the dependencies and repository, building container images and registering them.
The event helps you create better communication between loosely-coupled event consumers and producers for building the event-driven architecture. Knative puts these events in a queue that needed to be automatically performed without the developers’ script.
Later, these events are delivered to the containers. It then sends feeds to the event producers to perform tasks. This will reduce the developer’s workload in creating code for connection establishment.
A function is an independent deployment unit and a Knative serving service, like a microservice. Its code is written to perform a single task, such as:
- Processing a file in a database
- Saving a user to a database
- Performing a scheduled work
Knative serverless framework is designed to let you develop and deploy functions effectively and manage them.
Easily extend or overwrite the functionality of the Knative serverless framework using plugins. Every serverless.yml file contains a plugin property that features various plugins.
Resources are the Knative serverless infrastructure components that your function use, including:
- AWS SQS event source
- A scheduled task (run every 5 minutes, 10 minutes, etc.)
- A Kafka event source
Services are like a project. Hence, a service is the Knative serverless framework’s unit of organization. Though you can have many services for one application, you can think of the service as a project file.
It is where you will be capable of defining the functions, events, and resources, all in a single file entitled serverless.yml, serverless.json, or serverless.js. When you deploy the services with the serverless framework, everything in the file is deployed at once.
Knative-serving is built in Istio and Kubernetes that supports application deployment. It enables rapid development of serverless containers, network programming, and automatic scaling for Istio components. Knative-serving considers containers as a scalable service that can range from one instance to many container instances.
Features of Knative
Let’s discuss some of the features of the Knative serverless framework:
- Knative is a Kubernetes-based serverless framework that lets you deploy services to Kubernetes.
- It easily integrates Knative with the supported environment
- Developers can directly use Kubernetes API with the help of Knative to deploy serverless services
- It enables users to trigger serverless services with the help of the eventing system of Knative
How Does Knative Work?
Knative serverless framework works as an event steering segment and connects Istio and Kubernetes. Kubernetes works as the orchestrator for microservices and containers. Istio, on the other hand, is an open-source mesh tech that brings various components together to interact with the user and themselves.
Knative gives users multiple components targeted to carry out basic day-to-day work. These components are used again and again in a variety of applications. A developer can use any programming language. Hence, you do not require specific knowledge of languages as Knative recognizes container images only.
There are three components of the Knative serverless framework that are the keys to its functioning.
Building New Containers
The build component is responsible for building new containers. It can convert source codes to a container. Knative can be configured to meet business-specific needs.
First, Knative pulls out the source code from the library like Github. Then, underlying dependencies are added so that the code runs effectively. Container images are then constructed and put in files that the Kubernetes platform can access.
The container is made available to developers using Kubernetes and Knative. Thus, containers are built as long as the origin of the code is known.
Serving or Running the Platform
The serving component is responsible for the running of the platform. It involves:
- Configuration: Configuration is certain in managing multiple versions of the service. Each time there is a deployment of the new feature of a container, Knative saves the existing version and creates a new one with the latest changes and features. Moreover, Knative defines the state of a service.
- Auto-scaling: To better working serverless containers, you must be capable of autoscaling the containers either up or down. Knative can autoscale services to many if needed.
- Intelligent service routing: It is an important part of the Knative working mechanism. It lets developers direct the flow and amount of traffic to different existing versions of the microservices. While introducing new features and blue-green deployment strategies, intelligent service routing can be used.
It allows you to expose a fraction of users to the recent testing and version and gradually route vast traffic to the new version.
Eventing to Define Functions
The eventing component of Knative is responsible for describing the function of Knative. It allows defining the running of the containers based on events. Different events trigger specific functions of containers.
Developers can define the event triggers and the associated containers to let Knative do its job. Knative handles the list of events and delivery of the events.
Benefits of Knative
Knative provides services like route management, phased release, and service connection. It boasts a vast community. Let’s discuss how Knative influences companies to adopt this technology.
- Unlike other solutions, Knative has standard events and is compatible with the FaaS solution. It offers a CloudEvent standard framework that helps in designing serverless architecture.
- Although Knative is not a PaaS, it allows you to create a serverless PaaS with the serverless orchestration platform.
- Knative has a full-fledged and mature serverless design.
- It supports cross-platform and gives you a universal standard among cloud providers to eliminate the chance of binding vendors with a specific solution.
- Knative provides a flexible framework.
- It supports proportional phased releases.
- You can experience the serverless ecosystem within a containerized environment.
- Knative removes reliability on management and tooling.
- You can quickly migrate to other cloud providers that are integrated with Knative by implementing Kubernetes.
- It offers a request-driven compute model.
- It allows you to manage workflows as a service.
- With Knative, you can process IoT data, run accessibility checks, and validate configurations of your security groups.
- It allows developers to focus on the coding and let them create iterative code quickly.
- It ensures developers will incorporate new versions.
- Knative’s event-based model helps implement designs, including subscription, connection to the external system, and registration.
Challenges of Knative (and Some Solutions)
A Knative Framework that supports proper applications provides better performance at a minimal cost. However, an improper mix of applications can result in higher costs and underutilized container resources. This could lead to bad application performance, which is the biggest challenge of Knative serverless deployment.
Thus, a poorly sized resource pool or wrong applications can destroy many Knative benefits.
You can overcome this challenge by performing tests to verify resource quantities and the mix of applications on Knative. Measure the event loads by sizing the average and maximum loads for each and estimate the total consumption of resources. Repeat this for several applications to create and run a trial configuration to validate the estimates.
The functional challenges of Knative could be:
- Knative depends upon functions that fit a stateless model. This means no data is being stored in the component itself. Development of the functions is not a difficult phase, but it requires a slight shift in the approach, which means a single mistake can ruin the software’s performance.
- Business data consists of multiple steps transactions, and stateless functions maintain context across all the steps. Knative doesn’t have that capability as the public cloud serverless tools can do.
Regular monitoring and fixing issues can help you keep your performance at decent scores.
Compared to the serverless offerings in a public cloud, there is an operations challenge with Knative. Admins do not control the underlying servers with the public cloud. But, they will need to manage servers along with Kubernetes, containers, Knative, and Istio itself.
Knative minimally extends operations and development complexity for the companies that have already committed to Kubernetes and containers. Those committed to service mesh and microservices will find Knative a natural extension.
Use Cases of Knative
For applications that give rise to a variable number of events staying within or over time-established limits, Knative is best for them. Specific use cases of the Knative serverless framework include:
The event orientation is essential. If IT teams cannot imagine an application as a series of events instead of transactions, Knative may not be a good choice for functional and efficiency reasons.
Prerequisites and Installation of Knative
As we see in the above sections, Knative is a set of components like eventing and serving that runs on a service mesh and workload orchestration cluster. There are command line utilities that we need to install for straightforward operation. Thus, we need a few dependencies to ensure we can proceed with the installation.
There are several options to install Kubernetes. Docker Desktop comes to enable an easy Kubernetes cluster that serves various purposes. The simple approach is to use Kubernetes in Docker to run the Kubernetes cluster along with the Docker container nodes. The convenient way to work with the cluster is to use the Knative command-line tool.
The Knative CLI offers an easy and quick interface for creating its resources. It helps in complex tasks like traffic splitting and autoscaling. The convenient way is to download the compatible binary from the GitHub page.
Once we have all prerequisites, we can proceed to install the components. For the development environment, there is a quickstart plugin. The plugin helps in installing a local Knative cluster using the Knative client. You can download the quickstart plugin from the official release page.
Conclusion: The Future of Knative
Knative has replaced serverless computing by providing automatic scaling of applications. It makes a significant impact on the interoperable and modular system.
In the future, it’s expected that Knative will cover current shortcomings and become one of the most efficient technologies to run the serverless architecture.
Knative technology is more influential for developers by looking at its benefits over serverless alternatives. Knative will help you save a great time by replacing the need for building and maintaining the Kubernetes extensions. Developers are pretty happy with the Knative tech as it is easy to use and a great alternative to serverless solutions.
So, if you want to maximize the power of the Kubernetes environment in your cloud workflows, adopt Knative technology and witness the benefits yourself.