Docker Management Artifact-kubernetes-Introduction

1.1. What is Kubernetes?

A new approach to distributed architecture based on container technology

A complete distributed system support platform

Kubernetes is an open source project launched by the Google team, which aims to manage containers across multiple hosts, provide basic deployment, maintenance, and use scaling, primarily to implement the language as the Go language.

1.2. Basic Concepts

Node: In Kubernetes, the node is the point of actual work, and earlier versions are called Minion. A node can be either a virtual machine or a physical machine, depending on a clustered environment. Each node has some necessary services to run Pod container groups, and they can all be managed through the master node. The service processes running on node include Docker Daemon,kubelet and Kube-proxy.

Pod (container group): is the basic operating unit of the Kubernetes, which makes one or more of the relevant containers a pod, usually in pod containers running the same application. Pods contain containers that run on the same node, as a single snap-in that shares the same volumes and network NAMESPACE/IP and port space.

Pod life cycle: Pod life cycle is managed by replication controller. Throughout the process, the pod is in one of 4 states: Pending, Running, succeeded, Failed.

Replication Controller (RC): Used to define the number of pod replicas. Make sure that at any time a specified number of pod copies are running in the Kubernetes cluster, if less than a specified number of pod copies, the Replication controller launches a new pod, which in turn kills the excess to ensure that the quantity is constant.

Service: A service can be seen as a set of external access interfaces for pods that provide the same service.

Volume (storage volume): Volume is a shared directory that can be accessed by multiple containers in the pod .

Label : Key/value key-value pair used to differentiate pods, service, Replication controllers, pod, service, Replication controller can have multiple labels, However, each label key can only correspond to one value. Labels is the basis for service and replication controller operation, in order to forward requests for access to the service to multiple containers that provide services to the backend, it is by identifying the container's labels to select the correct container.

Proxy: It is designed to address the external network's ability to access application services provided across the container in a machine cluster. Proxy provides TCP/UDP sockets proxy, each creating a service,proxy mainly from ETCD to obtain services and endpoints configuration information, or can also be obtained from file, Then, based on the configuration information, a proxy process is started on Minion and the corresponding service port is monitored.

Namespace (namespace): By assigning the objects inside the system to different Namespace, different groupings of logic are formed to facilitate the sharing of resources across the cluster while simultaneously managing them separately.

Annotation (note): Similar to label, but label defines the metadata of the object, while Annotation is the "additional" information that is arbitrarily defined by the user.

This article is from the "Linux" blog, so be sure to keep this source http://syklinux.blog.51cto.com/9631548/1860268

Docker Management Artifact-kubernetes-Introduction