The speed of product launch is of great importance in IT production today. Developers need to bring their products to market at the right time and in the right way – the sooner the release, the more likely to stay ahead of competitors. And they can do that if they have the right tools on hand, those that help to simplify and accelerate the launch of new services and their updating. One of the most popular of such tools is Kubernetes.
Deploying applications with clusters running Kubernetes in the cloud is one of the most common scenarios in IT development. The container management system developed by Google has quickly become one of the biggest successes in open source history. In this article, we observe, why this tool is so popular.
The key to k8s popularity is that it enables to build an efficient development and testing process. The tool allows updating the necessary part of the application with simply one command, roll back the update, allocate additional resources, or reduce the capacity. With Kubernetes, companies can bring the product to market faster by reducing the time and risks associated with launching a new application into production.
Until recently, the ideal way to deploy an application was to pack it into an archive containing only code. Each programming language has its own way of packaging. For example, Java developers package the code into "jar" or "war" file. Another popular way to package software is to use packaging systems that are specific to your operating system. This is convenient as it is possible to include dependencies on external software.
Both approaches are functional but they can cause failures in releases. Applications can have dependencies that testers and users are not aware of, and that is only discovered during the deployment. For example, the developer system might significantly differ from the production environment. This leads to inconsistencies. Significant differences between development, testing, and production environments can potentially bear the risks at the stage of the final software release.
Containerization technology addresses these challenges. Containers bound the application code with all binary files and libraries needed to run an application. The image of the container contains everything you need to run the application, so it works consistently on the developer's, tester's, and user's device. Developers can move containers to any environment – to another server, to the cloud, etc., and it will work immediately, without the configuring of the environment, adding packages or other components.
Several different containers may run under the same operating system, but they work with their own libraries and isolate services from each other. Failure of one container does not lead to any consequences for others, and it can be almost instantly restarted, for example, on another machine in the cluster.
Containers can run in both physical and virtual environments. The second option has recently become popular, especially because of the high demand for containerized services on cloud platforms. In this regard, containers extend the virtualization paradigm, as they can use a single operating system and at the same time isolate the processes from each other, as well as allocate resources for them.
Kubernetes for container orchestration
According to research conducted by DigitalOcean, 49% of developers use containerization technology. Complex applications are typically designed with dozens and hundreds of containers. All of them should be managed. Here the platform for so-called container orchestration comes in handy. It automates container deployment, scaling, and life cycle management in a cluster of multiple servers. Kubernetes is one such platform.
The orchestration system determines where and how to arrange containers on the available resources, how to scale them, how to stop, move, and reload them, which computing resources to allocate. Kubernetes determines the configuration of the application, allows setting access rules for internal and external users to services inside containers. You may also set up automatic state monitoring, adding/reducing the number of containers. Similarly, server resources are dispatched to ensure that each container is allocated the necessary amount of resources. It is extremely difficult to do this manually because the load changes constantly and the dispatching is performed in real-time.
Kubernetes provides high availability of systems. Each configuration has one Master-node, which allocates tasks, stores configurations, performs planning, and monitoring. The Worker-nodes perform the payload, i.e. directly execute the containers with an application. If one executing node fails, the cluster continues to work and the containers are recreated on other work nodes. The system allows building configurations with several Master-nodes. Containers, due to their architecture, usually start quickly enough so that rebooting does not create additional delays.
How to implement Kubernetes in your organization
With orchestration tools, you can leverage on-premises resources as well as public cloud resources as a cluster. For example, you can use third-party capacities for development, while running the product in your data center. You work in the public cloud, and when you need to move the written application, just migrate all containers to the corporate IT infrastructure.
Employees who will work with k8s and containers must have the minimum necessary knowledge. A cloud provider offering the KaaS (Kubernetes-as-a-service) service can help them do this. The local deployment is more challenging, but tools such as kubeadm and kubespray make it easier to adopt the platform and start working with Kubernetes. If you just want to learn the platform, you can request test access to the service.
It is important to emphasize that Kubernetes will not solve all your problems but allows you to become more flexible and efficient by bringing your product to market faster.