Kubernetesis an open-source container orchestration system used for automating computer application deployment, scaling, and management. In other words, you use Kubernetes to make serious magic with containers. It has a large, rapidly growing ecosystem. Kubernetes services, support, and tools are widely available.
The name Kubernetes originates from Greek, meaning helmsman or pilot. Google open-sourced the Kubernetes project in 2014. Kubernetes combinesover 15 years of Google's experiencerunning production workloads at scale with best-of-breed ideas and practices from the community.
Here’s how Dan Kohn, executive director of theCloud Native Computing Foundation(CNCF),in a podcast with Gordon Haff, explained it: “Containerization is this trend that’s taking over the world to allow people to run all kinds of different applications in a variety of different environments. When they do that, they need an orchestration solution to keep track of all of those containers and schedule them and orchestrate them. Kubernetes is an increasingly popular way to do that.”
Node components run on every node, maintaining running pods and providing the Kubernetes runtime environment.
An agent that runs on eachnodein the cluster. It makes sure thatcontainersare running in aPod.
The kubelet takes a set of PodSpecs that are provided through various mechanisms and ensures that the containers described in those PodSpecs are running and healthy. The kubelet doesn't manage containers that were not created by Kubernetes.
kube-proxy is a network proxy that runs on eachnodein your cluster, implementing part of the KubernetesServiceconcept.
kube-proxymaintains network rules on nodes. These network rules allow network communication to your Pods from network sessions inside or outside of your cluster.
kube-proxy uses the operating system packet filtering layer if there is one and it's available. Otherwise, kube-proxy forwards the traffic itself.
The container runtime is the software that is responsible for running containers.
Kubernetes supports several container runtimes:Docker,containerd,CRI-O, and any implementation of theKubernetes CRI (Container Runtime Interface).
Addons use Kubernetes resources (DaemonSet,Deployment, etc) to implement cluster features. Because these are providing cluster-level features, namespaced resources for addons belong within the kube-system namespace.
Selected addons are described below.
While the other addons are not strictly required, all Kubernetes clusters should havecluster DNS, as many examples rely on it.
Cluster DNS is a DNS server, in addition to the other DNS server(s) in your environment, which serves DNS records for Kubernetes services.
Containers started by Kubernetes automatically include this DNS server in their DNS searches.
The dashboardis a general-purpose, web-based UI for Kubernetes clusters. It allows users to manage and troubleshoot applications running in the cluster, as well as the cluster itself.
Container Resource Monitoringrecords generic time-series metrics about containers in a central database and provides a UI for browsing that data.
Acluster-level loggingmechanism is responsible for saving container logs to a central log store with a search/browsing interface.
Key Features of Kubernetes:
Kubernetes (k8’s) is the next big wave in cloud computing and it’s easy to see why as businesses migrate their infrastructure and architecture to reflect a cloud-native, data-driven era.
