Kubernetes Operators: What Are They?
Kubernetes Operators: What Are They?
Running multiple stateful applications in Kubernetes gets tenuous and time-consuming without Kubernetes Operators to manage them.
Join the DZone community and get the full member experience.Join For Free
Kubernetes has become the gold standard for container orchestration. However, when it comes to running stateful applications, it needs to access a number of dependencies and operative tasks in order for it to function properly. As you can imagine, when doing this with thousands of containers, this is time-consuming and takes up a lot of developer resources, which is why you need Kubernetes Operators.
What Are Kubernetes Operators?
A Kubernetes Operator (usually just called Operator) refers to a method of packaging, deploying, and managing a Kubernetes application.
A Kubernetes application, on the other hand, is an application which is deployed on Kubernetes itself, and it is managed via the Kubernetes API and kubectl tooling. To get the most out of Kubernetes, you need to have access to a cohesive set of APIs which can be extended to service and manage your application that is running on Kubernetes. The Operators, in this instance, act as the runtime to manage this kind of application on Kubernetes.
Operators are seen as an extension of a software engineering team, as they assist in monitoring your Kubernetes environment and utilizes its current state or environment to make decisions in a matter of milliseconds. Essentially, an Operator takes in human operational knowledge and then encodes it into the software so that it can be easily packaged and shared with consumers.
Kubernetes Operators can handle a range of operative tasks from basic functionality to executing a specific logic for an application. More advanced Operators are able to react to failures automatically and handle upgrades.
It is important to note that not every Operator is the same; there’s no one-size-fits-all model. They are purpose-built to run a Kubernetes application.
Based on what we’ve seen, the Operator’s capabilities differ depending on how much logic, parameters, or functionality has been implemented into the Operator itself. And this will vary due to the needs and requirements of the business. We’ve also noticed that when developers are building an Operator, it usually starts off small by automating application installation and self-service provisioning, and then it evolves to handle more complex automation.
To ensure Operators have been built to a minimum standard, the Operator Framework was born.
The Operator Framework
The Operator Framework is an open source project that provides Kubernetes tools for both development and runtime. Most of these tools are available on GitHub.
The introduction of the Operator Framework marked a huge step for Kubernetes. It provides a baseline of practices to lower application development barrier on Kubernetes. The framework includes:
Operator Software Development Kit (SDK)
Operator Lifecycle Management
The Operator SDK provides developers with the key tools to build, test, and package Operators. When the Operator SDK was introduced, it was used to communicate the application’s business logic, whether that was scaling, upgrading or performing a backup, with the Kubernetes API for the logic to be executed. Now, the SDK can enable engineers to make their applications more intuitive and provide a user experience similar to that of a cloud-based service. The best practices and code patterns which are shared across the Operators are included in the SDK.
Operator Lifecycle Manager
Once the Operators have been built, they can then be deployed on a Kubernetes cluster. This is where the Operator Lifecycle Manager comes in. The Operator Lifecycle Manager helps facilitate the management of Operators on a Kubernetes cluster and its resources. Administrators are able to control which Operators are available in a particular namespace and they can assign who can interact with the Operators that are running.
For stateless applications, developers can leverage the Operator Lifecycle Manager’s features without writing any code through using a generic Operator that you can get on GitHub. But for complex and stateful applications, Operators can really showcase their benefits. With the cloud-like capabilities that are encoded into the Operator, developers can automate features like updates, backups, and scaling.
This is a recent addition to the Operator Framework which provides the ability to measure application usage. This will help IT teams keep a budget and take the necessary steps to optimize applications that are resource-heavy.
Key Advantages of The Operator Framework
Whether you are a developer or an end-user, the Operator Framework provides a number of advantages that you should know.
While Kubernetes has become the gold standard for container orchestration, there is often a high barrier to entry when it comes to developing Kubernetes applications. There is a number of pre-existing dependencies and assumptions to take into account, and many of these require a certain degree of expertise and technical knowledge. Also, developers need to be considerate about the needs of their end-users; they no longer want their services to be siloed and disparate.
The Operator Framework addresses these issues by bringing together the expertise and knowledge of the Kubernetes community in a single open source project to create a standard application package that developers can use to easily create their Kubernetes applications.
For users of applications across the hybrid cloud, it is crucial to keep these applications up-to-date, relevant, and secure, especially when consumer behavior is constantly changing at a rapid rate. The Operator Framework addresses these end-user requirements in helping developers create cloud native applications that are easier to consume, to keep secure, and to keep up-to-date.
Operators Are The Next Step In Kubernetes Applications
Operators are specially made for running a Kubernetes application. They are purpose-built with operational knowledge baked in. The cloud-based functionalities that are encoded into the Operator can provide an advanced user experience and can automate features like updates, backups, and scaling. All of which can be achieved via using the standard Kubernetes tools, CLI, and API.
Operators can be tailored to meet the needs of your organization, and they can be reused in various applications. To enable your developers to build their own operators, they can take advantage of the Operator Framework which provides the necessary tools to build, manage, and monitor the performance of your Operators.
Opinions expressed by DZone contributors are their own.