What is Kubernetes? Here’s what you need to know
Kubernetes (k8s or kube) is an open-source platform that automates Linux containers. A lot of work on containers in the standard approach is “manual” work, especially when it comes to creating and scaling applications based on containers. Its original version was created in 2014 by Google and is currently being developed by Cloud Native Computing Foundation. Kubernetes works with many container tools, including Docker. It is also supported by most public clouds and delivered in PaaS and IaaS. Many providers also offer their own Kubernetes distributions under a different name.
Work on Kubernetes began at the beginning of this decade: three Google engineers at the time: Joe Beda, Brendan Burns and Craig McLuckie decided to create a platform for managing, automating and scaling container applications. After that, they were joined by other employees of the giant, such as Brian Grant and Tim Hockin. In 2014, Google announced the first edition of Kubernetes, and the Borg system developed in Google has a significant impact on the development of the project. The original Borg project was written entirely in C++, but the rewritten Kubernetes system is implemented in Go.
Kubernetes – objects. What are they?
The main advantage of Kubernetes is its flexibility – all in order to make the most of it. Basically, the platform is simply a set of tools that provide mechanisms for deploying, maintaining and scaling applications based on the processor, memory and/or custom parameters. Flexibility is achieved through the Kubernetes API, which is used by internal components and extensions and containers launched by Kubernetes. The platform controls computational and memory resources, defining them as objects that can then be managed.
In Kubernetes, we distinguish: pods, namespaces, ReplicationController (Manages Pods), DeploymentController (Manages Pods), StatefulSets, DaemonSets, Services, ConfigMaps, Volumes. However, let’s deal with the most important of them:
Pods is an abstraction that groups together containerized components. A pod consists of one or more containers on the same host that can share resources. A pod is the smallest unit that can be run in Kubernetes. Services, on the other hand, are a set of pods cooperating with each other, just like one multilayer application. A set of pods constituting a service is defined by a label selector. It is worth noting Volumes: The file systems in the Kubernetes container provide ephemeral mass storage by default. This means that restarting will remove all data from such containers, so this form of storage is quite restrictive. The volumes Kubernetes provides a durable storage space that lasts for the entire life of the database.
Kubernetes provides shared resources by making them available on an exclusive basis using a namespace. Namespaces are designed for use in multi-user environments in multiple teams or projects, or even to separate environments such as development, testing, and production.
In what scenarios does Kubernetes come in handy?
Industry experts recognize that Kubernetes is particularly useful in applications such as moving applications to the cloud or creating machine learning and artificial intelligence projects. Kubernetes also allows you to easily scale, deploy and manage IoT devices. It is also very important that it simplifies the implementation and management of applications based on microservices.
The most important features
Kubernetes is able to automatically deploy containers on the basis of requirements in order to optimize the use of its resources. It maximizes their use and, at the same time, ensures that the “critical load” is not exceeded. Moreover, the platform is able to restart those containers that have failed: it also replaces those whose nodes have ceased to exist and destroys those that do not respond to the “status check”. Horizontal scaling is also important, allowing the application to scale up or down the cloud using simple commands, an interface or automatically based on the CPU load.
Kubernetes also uses media orchestration: it automatically assembles external memories selected by the user from local resources, from public clouds such as GCP and AWS, or network media such as NFS, iSCSI, Gluster, Ceph, Cinder, or Flocker. It is also important to deploy and update confidential information such as passwords and configure applications without rebuilding the image or revealing this confidential information in the configuration.
What are the advantages of Kubernetes?
It is free of charge and available under an open-source license. It works well in applications where high scalability counts and works with various PaaS systems, including GCE. Micro services are constantly updated and make it easy to group tasks with labels that allow you to identify objects according to different characteristics. The system is designed from the ground up to be fault-tolerant and able to handle parts failure, which is particularly useful for companies using clusters.
However, some disadvantages of Kubernetes must be taken into account: sometimes the containers need to be manually operated before they can function as intended. However, this only happens in certain scenarios. It is very important, however, that some reorganization should be carried out when starting to use Kubernetes in the context of an existing application – some companies may not like this from a business perspective. It is also worth noting that it uses a different configuration, YAML definition and API interface.
Technology that changes the world
Kubernetes is growing rapidly and has a huge community – its future seems to be bright. No wonder: Kubernetes facilitates certain processes that were highly problematic until its creation. The platform has become the main container orchestrator, thanks to its deep expertise, the adoption of the company and its solid ecosystem. As the orchestration of containers and microservices matures, they will open the door to the adoption of new deployment patterns, programming practices and business models.