ReplicaSet ensures that a specified number of Pod replicas are running at any given time.These Controllers are built upon the basic Kubernetes Objects and provide additional features. There are a number of Controllers provided by Kubernetes. Namespaces are virtual clusters backed by the physical cluster.Volume is essentially a directory accessible to all containers running in a Pod.Service is used to define a logical set of Pods and related policies used to access them.Quite often, but not necessarily, a Pod usually contains one container. It’s a group of containers which must run together. Pod is the smallest deployable unit on a Node.The basic Kubernetes objects are as follows: You can now directly interact with instances of Kubernetes Objects instead of interacting with containers. Kubernetes Objects also act as an additional layer of abstraction over the container interface. The state of the entities in the system at any given point of time is represented by Kubernetes Objects. By creating an object, you’re effectively telling the Kubernetes system what you want your cluster’s workload to look like this is your cluster’s desired state. Kubernetes ObjectsĪs defined in the Kubernetes Documentation: A Kubernetes object is a “record of intent”–once you create the object, the Kubernetes system will constantly work to ensure that object exists. You can use the kubectl which interacts directly with the cluster to set or modify the desired state through the Kubernetes API. This is enforced by Kubernetes Master which is a part of the Kubernetes Control Plane.
Kubernetes strictly ensures that all the containers running across the cluster are always in the desired state. If, due to some failure, the container stops running, Kubernetes recreates the Pod based on the lines of the desired state.
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You are free to define a state for the execution of containers inside Pods. The Desired Stateĭesired state is one of the core concepts of Kubernetes. To understand how Kubernetes works, we need to understand its underlying concepts and principles. Kubernetes is a very complex system as compared to Docker’s orchestration solution, Docker Swarm. There’s more to Kubernetes than meets the eye (and that’s why I am writing this in the first place). This was a birds eye view, but don’t stop here. Like containers, Kubernetes allows us to manage clusters, enabling the setup to be version controlled and replicated. This prevents bad rollouts before things actually go bad.Īdditionally, Kubernetes can scale services up or down based on utilisation, ensuring you’re only running what you need, when you need it, wherever you need it. Kubernetes automates rollouts, rollbacks, and monitors the health of deployed services. Kubernetes makes everything associated with deploying and managing containerised applications a joy. The lessons learned by Google working with Borg over the years became the guiding force behind Kubernetes. All powered by an internal platform called Borg (sounds more like some Orc warlord from Mordor, but no). Google deploys more than 2 billion containers a week. Alongside being vocal about its use of container technology, Kubernetes is the technology behind Google’s cloud service offerings. Google has long been a contributor to container technology. Kubernetes was developed and designed by the engineering team at Google. These clusters can span the public, private, and hybrid clouds - and who knows, the Star War universe one day. Kubernetes helps you manage those clusters. With Kubernetes, you can cluster groups of hosts running containers together.
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It eliminates most of the existing manual processes, which involve the deploying, scaling, and managing of containerized applications. Kubernetes, k8s, or kube, is an open source platform that automates container operations. Sounds pretty cool, huh? The best of both worlds packaged together as a single binary.
has packaged Kubernetes as an additional orchestration engine alongside Docker Swarm.įrom now on, Kubernetes will be a part of the Docker community and Docker Enterprise Edition.
Kubernetes was an instant hit, and starting this year, Docker Inc. Yet because of Docker, the use of Linux containers has become more prevalent, cementing the foundation for container orchestration engines.Įnter Kubernetes - developed by Google using years of experience running a world class infrastructure on billions of containers. Docker laid the foundation for the wide-spread use of containers, although container technology outdates it. brought containers to the lime light with their impeccable marketing of an amazing product. The reason for its instantaneous fame is the mighty containers.ĭocker Inc. It has attracted a lot of attention over the last few years. Kubernetes is one of the most exciting technologies in the world of DevOps these days.