Shulou(Shulou.com)06/02 Report--

1. Introduction to kubernetes 1.1 introduction to kubernetes

Kubernetes is a set of google open source micro services, containerized choreography engine, is the crystallization of more than a decade of practical precipitation of google internal containers, has defeated Swarm,Messo to become the industry standard for container choreography. Kuberntes has many excellent built-in features that allow developers to focus on the business itself, including the following features:

Service discovery and load balancing, service discovery and load balancing, internal parsing through DNS, load balancing Storage orchestration with service, storage orchestration, supporting multiple storage in the form of plungin, such as local, nfs,ceph, public cloud fast storage and other Automated rollouts and rollbacks, automatic publishing and rollback, matching current status with target state, rollback Automatic bin packing when update fails, automatic resource scheduling You can set the required (requests) resources and limited resources (limits) Self-healing for pod scheduling, built-in health check policy, automatically discover and handle exceptions in the cluster, replace, restart pod node Secret and configuration management, key and configuration management, store sensitive information such as passwords and accounts through secret, and store applied configuration files through configmap to avoid fixing configuration files in the image. Increase the flexibility of container choreography Batch execution, batch execution, through job and cronjob to provide a single batch task and circular scheduling task function to achieve Horizontal scaling, scale-out function, including HPA and AS, that is, the application's CPU utilization-based auto scaling and platform-based self-scaling, such as automatically adding node and deleting nodes nodes. 1.2 kubernetes architecture

Kubernetes includes two roles: master node and node node. Master node is the control and management node of the cluster and acts as the brain of the whole K8s cluster.

Responsible for all access requests (kube-apiserver) of the cluster, at the entrance of the entire cluster; cluster resource scheduling (kube-controller-scheduler), which monitors the creation of pod through watch, and is responsible for scheduling pod to appropriate node nodes; consistency of cluster state (kube-controller-manager), ensuring cluster consistency through multiple controllers, including Node Controller,Replication Controller,Endpoints Controller, etc. Metadata information storage (etcd), persistent storage of data, including node,pod,rc,service and other data in the storage cluster

A high-availability cluster is usually composed of 3 or 5 nodes, in which etcd is composed of clusters built-in, kube-apiserver is distributed by haproxy or nginx, and kube-scheduler and kube-controller-manager are guaranteed by built-in election mechanism to ensure that there is only one leader node in the cluster at a time, while the others are blocked to prevent brain fissure.

The node node is the actual working node, which is responsible for the actual operation of the cluster load, that is, the carrier of pod operation, which usually contains three components: Container Runtime,kubelet and kube-proxy.

Container Runtime is the container runtime and is responsible for implementing container lifecycle management. For example, docker,containerd,rktlet;kubelet is responsible for the management of images and pod, and kube-proxy is the spare time for the implementation of service services. It is responsible for maintaining and forwarding pod routes, and realizing access to internal and external networks of the cluster.

Other components include

Cloud-controller-manager, used for public cloud access implementation, provides node management (node), route management, service management (LoadBalancer and Ingress), and storage management (Volume, such as cloud disk, NAS access). Specific details need to be implemented by public cloud vendors. Kubernetes provides access to interfaces, such as CVM node management provided by Tencent Cloud. Integration of products such as node AS, load balancing access (CLB), storage management (CBS and CFS), etc. The DNS component implements name resolution in the cluster by kube-dns or coredns; kubernetes-dashboard is used for graphical interface management; kubectl command line tools for API interaction; the monitoring system is used to collect monitoring data from node and pod, such as prometheus,heapster+influxdb+grafana; log collection system, to collect container business data, to achieve log collection, storage and display, and to implement Fluentd+ELK (ElasticSearch+Logstash+Kiabana). 1.3 reference documentation

Introduction to kubernetes function, https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/

Introduction to kubernetes components https://kubernetes.io/docs/concepts/overview/components/

​

Return to the kubernetes series tutorial directory

* * if you think the article is helpful to you, please subscribe to the column and share it with friends in need.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.