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

Master node (Primary Node)

Linux: everything is a file

K8s: everything is a resource

Kubectl:k8s is the command line side, which is used to send the user's instructions.

Authorization (authentication and authorization mechanism)

API (programming interface)

API server: (back) is the front-end interface of the K8s cluster. Various client tools and other components of k8s can manage various resources of the k8s cluster. He provided HTTP/HTTPS RESTful API, or K8S API.

Scheduler: (meaning of scheduling) is responsible for deciding which node to run Pod on. In scheduling, the topology of the cluster, the current load of each node, and the high availability, performance, data affinity and requirements are fully taken into account.

Controller Manager: responsible for managing various resources in the cluster and ensuring that the resources are in the expected state. It consists of a variety of Controller (controllers), including Replication Controller. Endpoints Controller . Namespace Controller . Serviceaccounts Controller, wait.

Third-party components: he has an alternative. Consul,zookeeper .

Etcd: responsible for saving the configuration information of K8s cluster and the status information of various resources. When the data changes, etcd will quickly notify the relevant components of K8s.

* * the smallest component unit of a Pod:k8s cluster, within a Pod, can run one or more containers. In most cases, there is only one Container container in a Pod.

Flannel: it is a K8s cluster network solution, which can guarantee the cross-host communication of Pod.

Third-party solutions, there are also alternatives.

You can check the IP address and run on that node.

[root@master] # kubectl get pod-- all-namespaces-o wide

Node node:

Kubelet: he is the agent of node. When scheduler determines that Pod is running on a Node, it will send the specific configuration information of Pod to the kubelet,kubelet of that node, create and run containers based on this information, and report the running status to Master.

Kube-proxy: the container responsible for forwarding the TCP/UDP data flow accessing service to the backend. If there are multiple copies, kube-proxy will achieve load balancing.

Cadvisor: control

/ / run an example:

Create a deployment resource object, the pod controller

Kubectl run test-web-image=httpd-replicas=2

View:

[root@master] # kubectl get pod-o wide

[root@master] # kubectl get deployments.

Analyze the role of each component and the architecture workflow.

1 "kubectl sends deployment request to API server

2 "APIserver tells Controller Manager to create a Deployment resource

3 "Scheduler performs scheduling tasks, distributing two copies of Pod to node01 and node02

4 "kubelet on node01 and node2 creates and runs Pod on their respective nodes.

Add:

1. The configuration and current status information of the application are saved in etcd, and the data is read from etcd by API server when executing kubectl get pod.

2.Flannel allocates an IP for each Pod, but no Service resource is created at this time, and kube-proxy is not currently involved.

Kubectl run test-web-image=httpd-replicas=2

Kubectl get nodes

19 kubectl get deployments.

20 kubectl get pod

21 kubectl get pod-o wide

22 systemctl restart kubelet.service

23 kubectl get pod-o wide

24 kubectl delete pod test-web-5b56bdff65-fwp4l

26 kubectl get pod-o wide

2.Flannel recalled that each pod was assigned an ip, but there was no intrusion into service resources at this time, and kube-proxy has not yet participated in it.

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