Discover the benefits of Kubernetes for DevOps teams to orchestrate containers like Docker. Learn to run apps better, heal systems automatically, improve uptime, and keep costs down and users happy.
What is Kubernetes?
Kubernetes is an open-source container management system developed by Google and made available to the public in June 2014. The goal is to make deploying and managing complex distributed systems easier for developers interested in Linux containers. It was designed by Google engineers experienced with writing applications that run in a cluster.
Kubernetes – or K8s as it is commonly called – is the third container cluster manager developed by Google, improving core scheduling architecture and a shared persistent store at its core. Kubernetes APIs that process REST operations are similar to other APIs.
Of all the technologies to emerge over the past decade, Kubernetes is one of the most important. Automating management tasks that would not be feasible to perform by hand in most situations, plays a critical role in deploying containerized applications both in the cloud and on-premises.
However, Kubernetes is complex technology. Getting started with Kubernetes requires becoming familiar with several types of tools and concepts (like nodes, pods, clusters, and services). And, depending on exactly how you are using Kubernetes, the specific approach you take to getting started will vary.
How does Kubernetes work?
Kubernetes works by joining a group of physical or virtual host machines, referred to as “nodes”, into a cluster. This creates a “supercomputer” to run containerized applications with a greater processing speed, more storage capacity, and increased network capabilities than any single machine would have on its own. The nodes include all necessary services to run “pods”, which in turn run single or multiple containers. A pod corresponds to a single instance of an application in Kubernetes.
One (or more for larger clusters, or high availability) node of the cluster is designated as the “control plane”. The control plane node then assumes responsibility for the cluster as the orchestration layer – scheduling and allocating tasks to the “worker” nodes in a way that optimizes the resources of the cluster. All administrative and operational tasks on the cluster are done through the control plane, whether these are changes to the configuration, executing or terminating workloads, or controlling ingress and egress on the network.
The control plane is also responsible for monitoring all aspects of the cluster, enabling it to perform additional useful functions such as automatically reallocating workloads in case of failure, scaling up tasks that need more resources, and otherwise ensuring that the assigned workloads are always operating correctly.
Kubernetes has many features that help orchestrate containers across multiple hosts, automate the management of K8s clusters, and maximize resource usage through better utilization of infrastructure. Important features include:
- Auto-scaling. Automatically scale containerized applications and their resources up or down based on usage
- Lifecycle management. Automate deployments and updates with the ability to Rollback to previous versions and Pause and continue a deployment
- Declarative model. Declare the desired state, and K8s work in the background to maintain that state and recover from any failures
- Resilience and self-healing. Auto placement, auto restart, auto replication, and auto-scaling provide application self-healing
- Persistent storage. Ability to mount and add storage dynamically
- Load balancing. Kubernetes supports a variety of internal and external load balancing options to address diverse needs
- DevSecOps support. DevSecOps is an advanced approach to security that simplifies and automates container operations across clouds, integrates security throughout the container lifecycle, and enables teams to deliver secure, high-quality software more quickly. Combining DevSecOps practices and Kubernetes improves developer productivity.
There are multiple reasons to choose Kubernetes over any other contemporary container orchestration platform. Here are a few advantages:
- Portable and flexible: Kubernetes can work with any runtime and with varied infrastructure, including private cloud, public cloud, and on-premises servers, provided the host operating system has the required Linux and Windows version.
- Cost-effective for IT infrastructure: When the scale of your business is large, Kubernetes helps reduce your IT infrastructure costs as it packages together apps to ensure optimal usage of cloud and hardware investments. K8s have improved scalability and availability which decreases its use of human resources, who are then freed up to perform other tasks. Scaling up and scaling back applications depending on need optimizes infrastructure utilization.
- Multi-cloud competence: Kubernetes’ multi-cloud competence makes it a top-ranking facilitator. It can host workloads running on one cloud and multiple clouds. Most importantly, it can scale its environment from one cloud to another to reach the desired state of performance.
- Efficient and prompt marketing: Kubernetes’ microservices approach is elemental in allocating different tasks to smaller teams, improving agility and focus and so completing tasks in a shorter span. The IT teams manage large applications across multiple containers and handle/maintain them on an incredibly detailed level.
- Open source: As a community-led project, Kubernetes has many big corporate sponsors but is not owned by any one company, only overseen by CNCF which gives it an opportunity for manifold expansion. This means innovation comes more easily to Kubernetes compared with orchestrators that are close-sourced.
- Established and reliable: Not only has Kubernetes reduced cloud complexity, but it offers the most reliable solutions to developers. Kubernetes also has the advantage of having a large ecosystem of corresponding software projects and tools which can be made readily available to developers and IT engineers.
What Can You Do With Kubernetes?
Kubernetes allows companies to harness more computing power when running software applications. It automates the deployment, scheduling, and operation of application containers on clusters of machines – often hundreds of thousands or more – in private, cloud, or hybrid environments. It also allows developers to create a “container-centric” environment with container images deployed on Kubernetes or integrate with a continuous integration (CI) system.
As a platform, K8s can be combined with other technologies for added functionality and do not limit the types of applications or services that are supported. Some container-based Platform-as-a-Service (PaaS) systems run on Kubernetes. As a platform K8s differs from these PaaS systems in that it is not all-inclusive and does not provide middleware, deploy source code, build an application, or have a click-to-deploy marketplace.
What about Docker?
Docker can be used as a container runtime that Kubernetes orchestrates. When Kubernetes schedules a pod to a node, the kubelet on that node will instruct Docker to launch the specified containers.
The kubelet then continuously collects the status of those containers from Docker and aggregates that information in the control plane. Docker pulls containers onto that node and starts and stops those containers.
The difference when using Kubernetes with Docker is that an automated system asks Docker to do those things instead of the admin doing so manually on all nodes for all containers.
Kubernetes container management system allows enterprises to create an automated, virtual, microservices application platform. By using container services, organizations can build, deploy, and horizontally scale lightweight applications across multiple types of server hosts, cloud environments, and other infrastructures more efficiently.