What is 1.Kubernetes
• Kubernetes is referred K8S Google in 2014 a container open source cluster management system, Kubernetes.
• K8S for deploying containerized applications, extensions and management.
• K8S provides a container scheduling, resource scheduling, resilient and elastic, deployment management, service discovery and a series of functions.
• Kubernetes goal is to deploy container applications simple and efficient.
Official website: <U> http://www.kubernetes.io </ U>
2.Kubernetes 特性
(1) self-healing
restart when a node failure the failure of the container, replace and re-deploy, to ensure the desired number of copies; kill the health check fails container, and not before is not ready to handle client requests to ensure online uninterrupted service.
(2) elastically extensible
using a command, the UI or automatically based on the CPU usage and the rapid expansion of volume reduction application instance, to ensure high availability of the service peak concurrent application; resource recovery operations when the low peak, minimum cost to run the service.
(3) automatic deployment and rollback
K8S a rolling update policy update application, update a Pod, rather than delete all Pod, if a problem occurs during the update process, rolls back the changes, make sure the upgrade is not affected business.
(4) Service Discovery and load balancing
K8S multiple containers to provide a unified access to all container entrance (the internal IP address and a DNS name), and load balancing is associated, so that the user need not consider the vessel IP issues.
(5) Confidential and configuration management
of confidential data and application configuration, without the need to expose sensitive data in the image, the sensitive data to improve security. And may be in K8S, it is convenient to use some common application storage configuration.
(6) storage arrangement
mounted external storage systems, whether from local storage, public clouds (such as AWS), or network storage (such as NFS, GlusterFS, Ceph) are part of a cluster resource use, greatly improving the storage flexibility of use .
(7) Batch
one-time tasks, the timing task; scene satisfies batch data processing and analysis
3.Kubernetes cluster architecture and components
Master Components
(1) kube-apiserver
unified entrance Kubernetes API, clusters, each component coordinator, to provide RESTful API interface services, resource additions and deletions to all objects of investigation and monitoring operations to APIServer process for submission to the
Etcd storage.
(2) kube-controller-manager
processing cluster in routine background task, a resource corresponding to a controller, and ControllerManager is responsible for the management of these controllers.
(3) kube-scheduler
selecting a Node Pod newly created node according to the scheduling algorithm, can be arbitrarily deployed, can be deployed on a single node, it can be deployed on different nodes.
(4) etcd
distributed key-value storage system. For storing the cluster state data, such as object information Pod, Service and the like.
Node Components
(1) kubelet kubelet Node is the node in the Master Agent, the life cycle management of the machine running the container, such as creating a container, Pod mount data volume, downloads Secret, node status, and obtaining container work. Pod kubelet converting each into a group of containers.
(2) kube-proxy
implemented Pod Network Agent node Node, four rules and maintain the network load balancing work.
(3) docker rocket or
vessel engine, running the container.
4.Kubernetes core concepts
(. 1) Pod
minimum deployment means
a collection container of
a container Pod in a shared network namespace
Pod is short
(2) Controllers (Controller)
ReplicaSet: to ensure that the number of copies expected Pod
Deployment: stateless application deployment
StatefulSet: stateful application deployment
DaemonSet: Ensure that all run the same Node Pod
the Job: a one-time task
Cronjob: regular tasks
more advanced level objects , deploy and manage Pod
(3) Service
prevent lost to Pod
access policy defines a set of Pod
(4) Label: labels, attached to a resource, for the associated objects, query and filter
(5) Namespaces: namespace, the objects logically isolation
(6) annotations: Notes
Reproduced in: https: //www.jianshu.com/p/ee4b2651c9e7