kubernetes快速入門
作者：尹正傑
版權聲明：原創作品，謝絕轉載！否則將追究法律責任。
一.API Server客戶端命令工具kubectl使用入門
1>.查看kubectl命令的幫助信息
[root@master200.yinzhengjie.org.cn ~]# kubectl -h kubectl controls the Kubernetes cluster manager. Find more information at: https://kubernetes.io/docs/reference/kubectl/overview/ Basic Commands (Beginner): create Create a resource from a file or from stdin. expose Take a replication controller, service, deployment or pod and expose it as a new Kubernetes Service run Run a particular image on the cluster set Set specific features on objects Basic Commands (Intermediate): explain Documentation of resources get Display one or many resources edit Edit a resource on the server delete Delete resources by filenames, stdin, resources and names, or by resources and label selector Deploy Commands: rollout Manage the rollout of a resource scale Set a new size for a Deployment, ReplicaSet or Replication Controller autoscale Auto-scale a Deployment, ReplicaSet, or ReplicationController Cluster Management Commands: certificate Modify certificate resources. cluster-info Display cluster info top Display Resource (CPU/Memory/Storage) usage. cordon Mark node as unschedulable uncordon Mark node as schedulable drain Drain node in preparation for maintenance taint Update the taints on one or more nodes Troubleshooting and Debugging Commands: describe Show details of a specific resource or group of resources logs Print the logs for a container in a pod attach Attach to a running container exec Execute a command in a container port-forward Forward one or more local ports to a pod proxy Run a proxy to the Kubernetes API server cp Copy files and directories to and from containers. auth Inspect authorization Advanced Commands: diff Diff live version against would-be applied version apply Apply a configuration to a resource by filename or stdin patch Update field(s) of a resource using strategic merge patch replace Replace a resource by filename or stdin wait Experimental: Wait for a specific condition on one or many resources. convert Convert config files between different API versions kustomize Build a kustomization target from a directory or a remote url. Settings Commands: label Update the labels on a resource annotate Update the annotations on a resource completion Output shell completion code for the specified shell (bash or zsh) Other Commands: api-resources Print the supported API resources on the server api-versions Print the supported API versions on the server, in the form of "group/version" config Modify kubeconfig files plugin Provides utilities for interacting with plugins. version Print the client and server version information Usage: kubectl [flags] [options] Use "kubectl <command> --help" for more information about a given command. Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]#
2>.查看k8s node信息(需要注意的是,node是集群級別的資源)
[root@master200.yinzhengjie.org.cn ~]# kubectl get node NAME STATUS ROLES AGE VERSION master200.yinzhengjie.org.cn Ready master 9h v1.17.2 node201.yinzhengjie.org.cn Ready <none> 9h v1.17.2 node202.yinzhengjie.org.cn Ready <none> 8h v1.17.2 node203.yinzhengjie.org.cn Ready <none> 8h v1.17.2 [root@master200.yinzhengjie.org.cn ~]#
3>.查看k8s 集群的名稱空間
[root@master200.yinzhengjie.org.cn ~]# kubectl get ns #查看所有的名稱空間 NAME STATUS AGE default Active 9h kube-node-lease Active 9h kube-public Active 9h kube-system Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns default #查看指定的名稱空間 NAME STATUS AGE default Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns kube-node-lease NAME STATUS AGE kube-node-lease Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns kube-public NAME STATUS AGE kube-public Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns kube-system NAME STATUS AGE kube-system Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get namespace kube-system -o yaml #只查看kube-system的名稱空間信息並以yaml格式顯式 apiVersion: v1 kind: Namespace metadata: creationTimestamp: "2020-02-04T11:39:31Z" name: kube-system resourceVersion: "4" selfLink: /api/v1/namespaces/kube-system uid: bd3792cd-09e4-4ca8-848f-73ac8ea2748c spec: finalizers: - kubernetes status: phase: Active [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns/kube-system -o yaml #是上面的簡寫形式 apiVersion: v1 kind: Namespace metadata: creationTimestamp: "2020-02-04T11:39:31Z" name: kube-system resourceVersion: "4" selfLink: /api/v1/namespaces/kube-system uid: bd3792cd-09e4-4ca8-848f-73ac8ea2748c spec: finalizers: - kubernetes status: phase: Active [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get namespace kube-system -o json #只查看kube-system的名稱空間信息並以json格式顯式 { "apiVersion": "v1", "kind": "Namespace", "metadata": { "creationTimestamp": "2020-02-04T11:39:31Z", "name": "kube-system", "resourceVersion": "4", "selfLink": "/api/v1/namespaces/kube-system", "uid": "bd3792cd-09e4-4ca8-848f-73ac8ea2748c" }, "spec": { "finalizers": [ "kubernetes" ] }, "status": { "phase": "Active" } } [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns/kube-system -o json #很顯然，是上面的一種簡寫格式 { "apiVersion": "v1", "kind": "Namespace", "metadata": { "creationTimestamp": "2020-02-04T11:39:31Z", "name": "kube-system", "resourceVersion": "4", "selfLink": "/api/v1/namespaces/kube-system", "uid": "bd3792cd-09e4-4ca8-848f-73ac8ea2748c" }, "spec": { "finalizers": [ "kubernetes" ] }, "status": { "phase": "Active" } } [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
4>.查看指定名稱空間的pod(在k8s中容器被封裝成pod)
[root@master200.yinzhengjie.org.cn ~]# kubectl get pods -n kube-system NAME READY STATUS RESTARTS AGE coredns-6955765f44-455fh 1/1 Running 1 9h coredns-6955765f44-q6zqj 1/1 Running 1 9h etcd-master200.yinzhengjie.org.cn 1/1 Running 1 9h kube-apiserver-master200.yinzhengjie.org.cn 1/1 Running 1 9h kube-controller-manager-master200.yinzhengjie.org.cn 1/1 Running 1 9h kube-flannel-ds-amd64-hnnhb 1/1 Running 1 9h kube-flannel-ds-amd64-jhmh6 1/1 Running 1 8h kube-flannel-ds-amd64-lnldz 1/1 Running 2 9h kube-flannel-ds-amd64-nwv2l 1/1 Running 1 8h kube-proxy-2shb4 1/1 Running 1 9h kube-proxy-6r9dx 1/1 Running 1 9h kube-proxy-cg2m6 1/1 Running 1 8h kube-proxy-lp5pr 1/1 Running 1 8h kube-scheduler-master200.yinzhengjie.org.cn 1/1 Running 1 9h [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get pods -n kube-system -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES coredns-6955765f44-455fh 1/1 Running 1 9h 10.244.0.5 master200.yinzhengjie.org.cn <none> <none> coredns-6955765f44-q6zqj 1/1 Running 1 9h 10.244.0.4 master200.yinzhengjie.org.cn <none> <none> etcd-master200.yinzhengjie.org.cn 1/1 Running 1 9h 172.200.1.200 master200.yinzhengjie.org.cn <none> <none> kube-apiserver-master200.yinzhengjie.org.cn 1/1 Running 1 9h 172.200.1.200 master200.yinzhengjie.org.cn <none> <none> kube-controller-manager-master200.yinzhengjie.org.cn 1/1 Running 1 9h 172.200.1.200 master200.yinzhengjie.org.cn <none> <none> kube-flannel-ds-amd64-hnnhb 1/1 Running 1 9h 172.200.1.200 master200.yinzhengjie.org.cn <none> <none> kube-flannel-ds-amd64-jhmh6 1/1 Running 1 8h 172.200.1.203 node203.yinzhengjie.org.cn <none> <none> kube-flannel-ds-amd64-lnldz 1/1 Running 2 9h 172.200.1.201 node201.yinzhengjie.org.cn <none> <none> kube-flannel-ds-amd64-nwv2l 1/1 Running 1 8h 172.200.1.202 node202.yinzhengjie.org.cn <none> <none> kube-proxy-2shb4 1/1 Running 1 9h 172.200.1.201 node201.yinzhengjie.org.cn <none> <none> kube-proxy-6r9dx 1/1 Running 1 9h 172.200.1.200 master200.yinzhengjie.org.cn <none> <none> kube-proxy-cg2m6 1/1 Running 1 8h 172.200.1.202 node202.yinzhengjie.org.cn <none> <none> kube-proxy-lp5pr 1/1 Running 1 8h 172.200.1.203 node203.yinzhengjie.org.cn <none> <none> kube-scheduler-master200.yinzhengjie.org.cn 1/1 Running 1 9h 172.200.1.200 master200.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
5>.查看當前系統上支持的資源類型
[root@master200.yinzhengjie.org.cn ~]# kubectl api-resources #注意哈，NAME那一列是資源的名稱，但是由於有些資源名稱太長了，也有簡寫形式,即"SHORTNAMES"那一列,我在接下來會頻繁使用簡寫形式的資源類型 NAME SHORTNAMES APIGROUP NAMESPACED KIND bindings true Binding componentstatuses cs false ComponentStatus configmaps cm true ConfigMap endpoints ep true Endpoints events ev true Event limitranges limits true LimitRange namespaces ns false Namespace nodes no false Node persistentvolumeclaims pvc true PersistentVolumeClaim persistentvolumes pv false PersistentVolume pods po true Pod podtemplates true PodTemplate replicationcontrollers rc true ReplicationController resourcequotas quota true ResourceQuota secrets true Secret serviceaccounts sa true ServiceAccount services svc true Service mutatingwebhookconfigurations admissionregistration.k8s.io false MutatingWebhookConfiguration validatingwebhookconfigurations admissionregistration.k8s.io false ValidatingWebhookConfiguration customresourcedefinitions crd,crds apiextensions.k8s.io false CustomResourceDefinition apiservices apiregistration.k8s.io false APIService controllerrevisions apps true ControllerRevision daemonsets ds apps true DaemonSet deployments deploy apps true Deployment replicasets rs apps true ReplicaSet statefulsets sts apps true StatefulSet tokenreviews authentication.k8s.io false TokenReview localsubjectaccessreviews authorization.k8s.io true LocalSubjectAccessReview selfsubjectaccessreviews authorization.k8s.io false SelfSubjectAccessReview selfsubjectrulesreviews authorization.k8s.io false SelfSubjectRulesReview subjectaccessreviews authorization.k8s.io false SubjectAccessReview horizontalpodautoscalers hpa autoscaling true HorizontalPodAutoscaler cronjobs cj batch true CronJob jobs batch true Job certificatesigningrequests csr certificates.k8s.io false CertificateSigningRequest leases coordination.k8s.io true Lease endpointslices discovery.k8s.io true EndpointSlice events ev events.k8s.io true Event ingresses ing extensions true Ingress ingresses ing networking.k8s.io true Ingress networkpolicies netpol networking.k8s.io true NetworkPolicy runtimeclasses node.k8s.io false RuntimeClass poddisruptionbudgets pdb policy true PodDisruptionBudget podsecuritypolicies psp policy false PodSecurityPolicy clusterrolebindings rbac.authorization.k8s.io false ClusterRoleBinding clusterroles rbac.authorization.k8s.io false ClusterRole rolebindings rbac.authorization.k8s.io true RoleBinding roles rbac.authorization.k8s.io true Role priorityclasses pc scheduling.k8s.io false PriorityClass csidrivers storage.k8s.io false CSIDriver csinodes storage.k8s.io false CSINode storageclasses sc storage.k8s.io false StorageClass volumeattachments storage.k8s.io false VolumeAttachment [root@master200.yinzhengjie.org.cn ~]#
6>.查看當前集群的deployments控制器
[root@master200.yinzhengjie.org.cn ~]# kubectl get deploy -n kube-system -o wide NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR coredns 2/2 2 2 9h coredns k8s.gcr.io/coredns:1.6.5 k8s-app=kube-dns [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
7>.創建資源(以創建名稱空間為案例)
[root@master200.yinzhengjie.org.cn ~]# kubectl create --help Create a resource from a file or from stdin. JSON and YAML formats are accepted. Examples: # Create a pod using the data in pod.json. kubectl create -f ./pod.json # Create a pod based on the JSON passed into stdin. cat pod.json | kubectl create -f - # Edit the data in docker-registry.yaml in JSON then create the resource using the edited data. kubectl create -f docker-registry.yaml --edit -o json Available Commands: clusterrole Create a ClusterRole. clusterrolebinding Create a ClusterRoleBinding for a particular ClusterRole configmap Create a configmap from a local file, directory or literal value cronjob Create a cronjob with the specified name. deployment Create a deployment with the specified name. job Create a job with the specified name. namespace Create a namespace with the specified name poddisruptionbudget Create a pod disruption budget with the specified name. priorityclass Create a priorityclass with the specified name. quota Create a quota with the specified name. role Create a role with single rule. rolebinding Create a RoleBinding for a particular Role or ClusterRole secret Create a secret using specified subcommand service Create a service using specified subcommand. serviceaccount Create a service account with the specified name Options: --allow-missing-template-keys=true: If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. --dry-run=false: If true, only print the object that would be sent, without sending it. --edit=false: Edit the API resource before creating -f, --filename=[]: Filename, directory, or URL to files to use to create the resource -k, --kustomize='': Process the kustomization directory. This flag can't be used together with -f or -R. -o, --output='': Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-file. --raw='': Raw URI to POST to the server. Uses the transport specified by the kubeconfig file. --record=false: Record current kubectl command in the resource annotation. If set to false, do not record the command. If set to true, record the command. If not set, default to updating the existing annotation value only if one already exists. -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage related manifests organized within the same directory. --save-config=false: If true, the configuration of current object will be saved in its annotation. Otherwise, the annotation will be unchanged. This flag is useful when you want to perform kubectl apply on this object in the future. -l, --selector='': Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2) --template='': Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview]. --validate=true: If true, use a schema to validate the input before sending it --windows-line-endings=false: Only relevant if --edit=true. Defaults to the line ending native to your platform. Usage: kubectl create -f FILENAME [options] Use "kubectl <command> --help" for more information about a given command. Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get namespace #查看名稱空間 NAME STATUS AGE default Active 9h kube-node-lease Active 9h kube-public Active 9h kube-system Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns #也是查看名稱空間，只不過這里是簡寫形式而已 NAME STATUS AGE default Active 9h kube-node-lease Active 9h kube-public Active 9h kube-system Active 9h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl create namespace operation #創建一個叫做"operation"的名稱空間 namespace/operation created [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl create ns development namespace/development created [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl create ns testing namespace/testing created [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get ns NAME STATUS AGE default Active 9h development Active 38s kube-node-lease Active 9h kube-public Active 9h kube-system Active 9h operation Active 65s testing Active 3s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
8>.刪除資源(以刪除名稱空間為案例)
[root@master200.yinzhengjie.org.cn ~]# kubectl delete --help Delete resources by filenames, stdin, resources and names, or by resources and label selector. JSON and YAML formats are accepted. Only one type of the arguments may be specified: filenames, resources and names, or resources and label selector. Some resources, such as pods, support graceful deletion. These resources define a default period before they are forcibly terminated (the grace period) but you may override that value with the --grace-period flag, or pass --now to set a grace-period of 1. Because these resources often represent entities in the cluster, deletion may not be acknowledged immediately. If the node hosting a pod is down or cannot reach the API server, termination may take significantly longer than the grace period. To force delete a resource, you must pass a grace period of 0 and specify the --force flag. Note: only a subset of resources support graceful deletion. In absence of the support, --grace-period is ignored. IMPORTANT: Force deleting pods does not wait for confirmation that the pod's processes have been terminated, which can leave those processes running until the node detects the deletion and completes graceful deletion. If your processes use shared storage or talk to a remote API and depend on the name of the pod to identify themselves, force deleting those pods may result in multiple processes running on different machines using the same identification which may lead to data corruption or inconsistency. Only force delete pods when you are sure the pod is terminated, or if your application can tolerate multiple copies of the same pod running at once. Also, if you force delete pods the scheduler may place new pods on those nodes before the node has released those resources and causing those pods to be evicted immediately. Note that the delete command does NOT do resource version checks, so if someone submits an update to a resource right when you submit a delete, their update will be lost along with the rest of the resource. Examples: # Delete a pod using the type and name specified in pod.json. kubectl delete -f ./pod.json # Delete resources from a directory containing kustomization.yaml - e.g. dir/kustomization.yaml. kubectl delete -k dir # Delete a pod based on the type and name in the JSON passed into stdin. cat pod.json | kubectl delete -f - # Delete pods and services with same names "baz" and "foo" kubectl delete pod,service baz foo # Delete pods and services with label name=myLabel. kubectl delete pods,services -l name=myLabel # Delete a pod with minimal delay kubectl delete pod foo --now # Force delete a pod on a dead node kubectl delete pod foo --grace-period=0 --force # Delete all pods kubectl delete pods --all Options: --all=false: Delete all resources, including uninitialized ones, in the namespace of the specified resource types. -A, --all-namespaces=false: If present, list the requested object(s) across all namespaces. Namespace in current context is ignored even if specified with --namespace. --cascade=true: If true, cascade the deletion of the resources managed by this resource (e.g. Pods created by a ReplicationController). Default true. --field-selector='': Selector (field query) to filter on, supports '=', '==', and '!='.(e.g. --field-selector key1=value1,key2=value2). The server only supports a limited number of field queries per type. -f, --filename=[]: containing the resource to delete. --force=false: Only used when grace-period=0. If true, immediately remove resources from API and bypass graceful deletion. Note that immediate deletion of some resources may result in inconsistency or data loss and requires confirmation. --grace-period=-1: Period of time in seconds given to the resource to terminate gracefully. Ignored if negative. Set to 1 for immediate shutdown. Can only be set to 0 when --force is true (force deletion). --ignore-not-found=false: Treat "resource not found" as a successful delete. Defaults to "true" when --all is specified. -k, --kustomize='': Process a kustomization directory. This flag can't be used together with -f or -R. --now=false: If true, resources are signaled for immediate shutdown (same as --grace-period=1). -o, --output='': Output mode. Use "-o name" for shorter output (resource/name). --raw='': Raw URI to DELETE to the server. Uses the transport specified by the kubeconfig file. -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage related manifests organized within the same directory. -l, --selector='': Selector (label query) to filter on, not including uninitialized ones. --timeout=0s: The length of time to wait before giving up on a delete, zero means determine a timeout from the size of the object --wait=true: If true, wait for resources to be gone before returning. This waits for finalizers. Usage: kubectl delete ([-f FILENAME] | [-k DIRECTORY] | TYPE [(NAME | -l label | --all)]) [options] Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get ns NAME STATUS AGE default Active 10h development Active 7m14s kube-node-lease Active 10h kube-public Active 10h kube-system Active 10h operation Active 7m41s testing Active 6m39s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl delete ns operation #刪除名稱為"operation"名稱空間,如果想要刪除多個名稱空間使用空格隔開即可(刪除資源時會刪除該名稱空間下的所有pods資源,因此刪除名稱空間是很危險的操作，生產環境要謹慎操作哈~) namespace "operation" deleted [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl delete ns/development ns/testing #當然，我們也可以使用這種方式刪除多個名稱空間 namespace "development" deleted [root@master200.yinzhengjie.org.cn ~]# namespace "testing" deleted [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get namespace NAME STATUS AGE default Active 10h kube-node-lease Active 10h kube-public Active 10h kube-system Active 10h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
9>.查看資源的描述信息
[root@master200.yinzhengjie.org.cn ~]# kubectl get ns NAME STATUS AGE default Active 10h kube-node-lease Active 10h kube-public Active 10h kube-system Active 10h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl describe ns/kube-system Name: kube-system Labels: <none> Annotations: <none> Status: Active No resource quota. No LimitRange resource. [root@master200.yinzhengjie.org.cn ~]#
10>.創建service
[root@master200.yinzhengjie.org.cn ~]# kubectl create service --help Create a service using specified subcommand. Aliases: service, svc Available Commands: clusterip Create a ClusterIP service. externalname Create an ExternalName service. loadbalancer Create a LoadBalancer service. nodeport Create a NodePort service. Usage: kubectl create service [flags] [options] Use "kubectl <command> --help" for more information about a given command. Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl create service clusterip --help Create a ClusterIP service with the specified name. Examples: # Create a new ClusterIP service named my-cs kubectl create service clusterip my-cs --tcp=5678:8080 # Create a new ClusterIP service named my-cs (in headless mode) kubectl create service clusterip my-cs --clusterip="None" Options: --allow-missing-template-keys=true: If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. --clusterip='': Assign your own ClusterIP or set to 'None' for a 'headless' service (no loadbalancing). --dry-run=false: If true, only print the object that would be sent, without sending it. --generator='service-clusterip/v1': The name of the API generator to use. -o, --output='': Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-file. --save-config=false: If true, the configuration of current object will be saved in its annotation. Otherwise, the annotation will be unchanged. This flag is useful when you want to perform kubectl apply on this object in the future. --tcp=[]: Port pairs can be specified as '<port>:<targetPort>'. --template='': Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview]. --validate=true: If true, use a schema to validate the input before sending it Usage: kubectl create service clusterip NAME [--tcp=<port>:<targetPort>] [--dry-run] [options] Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl create service clusterip nginx-service --tcp=80:80 #創建一個名稱為"nginx-service"的service資源，指定tcp 80端口映射到目標的80端口，IP地址會動態分配 service/nginx-service created [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h nginx-service ClusterIP 10.111.57.222 <none> 80/TCP 1s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h nginx-service ClusterIP 10.111.57.222 <none> 80/TCP 2m24s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h nginx-service ClusterIP 10.111.57.222 <none> 80/TCP 2m33s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get service/nginx-service -o yaml #以yaml格式顯式service服務 apiVersion: v1 kind: Service metadata: creationTimestamp: "2020-02-04T23:23:14Z" labels: app: nginx-service name: nginx-service namespace: default resourceVersion: "31112" selfLink: /api/v1/namespaces/default/services/nginx-service uid: 3e32c499-5cdd-4986-bca1-abff14c31ee8 spec: clusterIP: 10.111.57.222 ports: - name: 80-80 port: 80 protocol: TCP targetPort: 80 selector: app: nginx-service sessionAffinity: None type: ClusterIP status: loadBalancer: {} [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
11>.刪除service
[root@master200.yinzhengjie.org.cn ~]# kubectl delete service --help Delete resources by filenames, stdin, resources and names, or by resources and label selector. JSON and YAML formats are accepted. Only one type of the arguments may be specified: filenames, resources and names, or resources and label selector. Some resources, such as pods, support graceful deletion. These resources define a default period before they are forcibly terminated (the grace period) but you may override that value with the --grace-period flag, or pass --now to set a grace-period of 1. Because these resources often represent entities in the cluster, deletion may not be acknowledged immediately. If the node hosting a pod is down or cannot reach the API server, termination may take significantly longer than the grace period. To force delete a resource, you must pass a grace period of 0 and specify the --force flag. Note: only a subset of resources support graceful deletion. In absence of the support, --grace-period is ignored. IMPORTANT: Force deleting pods does not wait for confirmation that the pod's processes have been terminated, which can leave those processes running until the node detects the deletion and completes graceful deletion. If your processes use shared storage or talk to a remote API and depend on the name of the pod to identify themselves, force deleting those pods may result in multiple processes running on different machines using the same identification which may lead to data corruption or inconsistency. Only force delete pods when you are sure the pod is terminated, or if your application can tolerate multiple copies of the same pod running at once. Also, if you force delete pods the scheduler may place new pods on those nodes before the node has released those resources and causing those pods to be evicted immediately. Note that the delete command does NOT do resource version checks, so if someone submits an update to a resource right when you submit a delete, their update will be lost along with the rest of the resource. Examples: # Delete a pod using the type and name specified in pod.json. kubectl delete -f ./pod.json # Delete resources from a directory containing kustomization.yaml - e.g. dir/kustomization.yaml. kubectl delete -k dir # Delete a pod based on the type and name in the JSON passed into stdin. cat pod.json | kubectl delete -f - # Delete pods and services with same names "baz" and "foo" kubectl delete pod,service baz foo # Delete pods and services with label name=myLabel. kubectl delete pods,services -l name=myLabel # Delete a pod with minimal delay kubectl delete pod foo --now # Force delete a pod on a dead node kubectl delete pod foo --grace-period=0 --force # Delete all pods kubectl delete pods --all Options: --all=false: Delete all resources, including uninitialized ones, in the namespace of the specified resource types. -A, --all-namespaces=false: If present, list the requested object(s) across all namespaces. Namespace in current context is ignored even if specified with --namespace. --cascade=true: If true, cascade the deletion of the resources managed by this resource (e.g. Pods created by a ReplicationController). Default true. --field-selector='': Selector (field query) to filter on, supports '=', '==', and '!='.(e.g. --field-selector key1=value1,key2=value2). The server only supports a limited number of field queries per type. -f, --filename=[]: containing the resource to delete. --force=false: Only used when grace-period=0. If true, immediately remove resources from API and bypass graceful deletion. Note that immediate deletion of some resources may result in inconsistency or data loss and requires confirmation. --grace-period=-1: Period of time in seconds given to the resource to terminate gracefully. Ignored if negative. Set to 1 for immediate shutdown. Can only be set to 0 when --force is true (force deletion). --ignore-not-found=false: Treat "resource not found" as a successful delete. Defaults to "true" when --all is specified. -k, --kustomize='': Process a kustomization directory. This flag can't be used together with -f or -R. --now=false: If true, resources are signaled for immediate shutdown (same as --grace-period=1). -o, --output='': Output mode. Use "-o name" for shorter output (resource/name). --raw='': Raw URI to DELETE to the server. Uses the transport specified by the kubeconfig file. -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage related manifests organized within the same directory. -l, --selector='': Selector (label query) to filter on, not including uninitialized ones. --timeout=0s: The length of time to wait before giving up on a delete, zero means determine a timeout from the size of the object --wait=true: If true, wait for resources to be gone before returning. This waits for finalizers. Usage: kubectl delete ([-f FILENAME] | [-k DIRECTORY] | TYPE [(NAME | -l label | --all)]) [options] Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h nginx-service ClusterIP 10.111.57.222 <none> 80/TCP 7m8s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl delete service/nginx-service service "nginx-service" deleted [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
12>.以“組/版本”的形式打印服務器上支持的API版本
[root@master200.yinzhengjie.org.cn ~]# kubectl api-versions admissionregistration.k8s.io/v1 admissionregistration.k8s.io/v1beta1 apiextensions.k8s.io/v1 apiextensions.k8s.io/v1beta1 apiregistration.k8s.io/v1 apiregistration.k8s.io/v1beta1 apps/v1 authentication.k8s.io/v1 authentication.k8s.io/v1beta1 authorization.k8s.io/v1 authorization.k8s.io/v1beta1 autoscaling/v1 autoscaling/v2beta1 autoscaling/v2beta2 batch/v1 batch/v1beta1 certificates.k8s.io/v1beta1 coordination.k8s.io/v1 coordination.k8s.io/v1beta1 discovery.k8s.io/v1beta1 events.k8s.io/v1beta1 extensions/v1beta1 networking.k8s.io/v1 networking.k8s.io/v1beta1 node.k8s.io/v1beta1 policy/v1beta1 rbac.authorization.k8s.io/v1 rbac.authorization.k8s.io/v1beta1 scheduling.k8s.io/v1 scheduling.k8s.io/v1beta1 storage.k8s.io/v1 storage.k8s.io/v1beta1 v1 [root@master200.yinzhengjie.org.cn ~]#
13>.監控(watch)正在運行的pod
[root@master200.yinzhengjie.org.cn ~]# kubectl get pods -w NAME READY STATUS RESTARTS AGE liveness-exec 1/1 Running 6 9m58s liveness-http 1/1 Running 0 8s mynginx-677d85dbd5-t9xfz 1/1 Running 0 4h36m
二.使用kubectl部署一個nginx鏡像案例
1>.創建容器之前查看default名稱空間信息
[root@master200.yinzhengjie.org.cn ~]# kubectl get ns NAME STATUS AGE default Active 10h kube-node-lease Active 10h kube-public Active 10h kube-system Active 10h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get all #注意，此處我們沒有指定名稱空間，那么就是使用的default這個名稱空間喲~ NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 10h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get all -n default #查看default名稱空間的所有資源 NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 10h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pods #如果咱們沒有指定名稱空間，默認使用的就是default這個名稱空間喲~ No resources found in default namespace. [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pods -n default #查看default名稱空間的pods信息 No resources found in default namespace. [root@master200.yinzhengjie.org.cn ~]#
2>.創建一個nginx的pod
[root@master200.yinzhengjie.org.cn ~]# kubectl create deploy --help Create a deployment with the specified name. Aliases: deployment, deploy Examples: # Create a new deployment named my-dep that runs the busybox image. kubectl create deployment my-dep --image=busybox Options: --allow-missing-template-keys=true: If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. --dry-run=false: If true, only print the object that would be sent, without sending it. --generator='': The name of the API generator to use. --image=[]: Image name to run. -o, --output='': Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-file. --save-config=false: If true, the configuration of current object will be saved in its annotation. Otherwise, the annotation will be unchanged. This flag is useful when you want to perform kubectl apply on this object in the future. --template='': Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview]. --validate=true: If true, use a schema to validate the input before sending it Usage: kubectl create deployment NAME --image=image [--dry-run] [options] Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl create deploy mynginx --image=nginx:1.14-alpine #注意，部署應用時名稱不要出現大寫字母(即盡量不要使用駝峰命名法)，名稱可以使用"-"或者"."進行分割，指定鏡像為"nginx:1.14-alpine" deployment.apps/mynginx created [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get all NAME READY STATUS RESTARTS AGE pod/mynginx-677d85dbd5-zjt8v 1/1 Running 0 17s NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 10h NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/mynginx 1/1 1 1 17s NAME DESIRED CURRENT READY AGE replicaset.apps/mynginx-677d85dbd5 1 1 1 17s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mynginx-677d85dbd5-zjt8v 1/1 Running 0 80s [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-zjt8v 1/1 Running 0 88s 10.244.3.2 node203.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
3>.訪問上一步創建的mynginx pod的IP地址可以獲得nginx的默認頁面
[root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-zjt8v 1/1 Running 0 5m28s 10.244.3.2 node203.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# curl 10.244.3.2 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
4>.手動刪除pod后k8s會自動幫咱們去創建一個pod
[root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-zjt8v 1/1 Running 0 12m 10.244.3.2 node203.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl delete pods/mynginx-677d85dbd5-zjt8v pod "mynginx-677d85dbd5-zjt8v" deleted [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-l5xw2 1/1 Running 0 22s 10.244.1.2 node201.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]#
5>.為pods擴容
[root@master200.yinzhengjie.org.cn ~]# kubectl scale --help Set a new size for a Deployment, ReplicaSet, Replication Controller, or StatefulSet. Scale also allows users to specify one or more preconditions for the scale action. If --current-replicas or --resource-version is specified, it is validated before the scale is attempted, and it is guaranteed that the precondition holds true when the scale is sent to the server. Examples: # Scale a replicaset named 'foo' to 3. kubectl scale --replicas=3 rs/foo # Scale a resource identified by type and name specified in "foo.yaml" to 3. kubectl scale --replicas=3 -f foo.yaml # If the deployment named mysql's current size is 2, scale mysql to 3. kubectl scale --current-replicas=2 --replicas=3 deployment/mysql # Scale multiple replication controllers. kubectl scale --replicas=5 rc/foo rc/bar rc/baz # Scale statefulset named 'web' to 3. kubectl scale --replicas=3 statefulset/web Options: --all=false: Select all resources in the namespace of the specified resource types --allow-missing-template-keys=true: If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. --current-replicas=-1: Precondition for current size. Requires that the current size of the resource match this value in order to scale. -f, --filename=[]: Filename, directory, or URL to files identifying the resource to set a new size -k, --kustomize='': Process the kustomization directory. This flag can't be used together with -f or -R. -o, --output='': Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-file. --record=false: Record current kubectl command in the resource annotation. If set to false, do not record the command. If set to true, record the command. If not set, default to updating the existing annotation value only if one already exists. -R, --recursive=false: Process the directory used in -f, --filename recursively. Useful when you want to manage related manifests organized within the same directory. --replicas=0: The new desired number of replicas. Required. --resource-version='': Precondition for resource version. Requires that the current resource version match this value in order to scale. -l, --selector='': Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2) --template='': Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview]. --timeout=0s: The length of time to wait before giving up on a scale operation, zero means don't wait. Any other values should contain a corresponding time unit (e.g. 1s, 2m, 3h). Usage: kubectl scale [--resource-version=version] [--current-replicas=count] --replicas=COUNT (-f FILENAME | TYPE NAME) [options] Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mynginx-677d85dbd5-vk5p5 1/1 Running 0 27m [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl scale --replicas=3 deployment mynginx #我們將自己創建的mynginx應用的副本設置為3，模擬擴容 deployment.apps/mynginx scaled [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mynginx-677d85dbd5-gkdb6 1/1 Running 0 2s mynginx-677d85dbd5-vb8tt 1/1 Running 0 2s mynginx-677d85dbd5-vk5p5 1/1 Running 0 28m [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
6>.為pods縮容
[root@master200.yinzhengjie.org.cn ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mynginx-677d85dbd5-gkdb6 1/1 Running 0 4m37s mynginx-677d85dbd5-vb8tt 1/1 Running 0 4m37s mynginx-677d85dbd5-vk5p5 1/1 Running 0 32m [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl scale --replicas=2 deployment mynginx #我們將副本設置為2，模擬縮容 deployment.apps/mynginx scaled [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mynginx-677d85dbd5-gkdb6 1/1 Running 0 4m46s mynginx-677d85dbd5-vk5p5 1/1 Running 0 32m [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
三.使用kubectl創建一個service
1>.查看現有的service
[root@master200.yinzhengjie.org.cn ~]# kubectl get service #查看現有的service資源 NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get svc #是上面的簡寫形式 NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
2>.創建一個service資源(我們可以使用service的IP去訪問關聯的pod資源，如下圖所示，訪問10.109.254.211:80其實訪問的就是10.244.1.2:80喲~)
[root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl create service clusterip mynginx --tcp=80:80 #注意，此處我故意創建了一個和上面pod同名的服務，這樣創建后它會自動和上面咱們創建的nginx pod進行關聯 service/mynginx created [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11h mynginx ClusterIP 10.109.254.211 <none> 80/TCP 9s [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get service/mynginx -o yaml #以yaml格式顯式名稱為"mynginx"的service資源信息 apiVersion: v1 kind: Service metadata: creationTimestamp: "2020-02-04T23:33:33Z" labels: app: mynginx name: mynginx namespace: default resourceVersion: "32669" selfLink: /api/v1/namespaces/default/services/mynginx uid: 19b9ddeb-a630-4637-a854-5f1750e7aaf0 spec: clusterIP: 10.109.254.211 ports: - name: 80-80 port: 80 protocol: TCP targetPort: 80 selector: app: mynginx sessionAffinity: None type: ClusterIP status: loadBalancer: {} [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-l5xw2 1/1 Running 0 70m 10.244.1.2 node201.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl describe svc/mynginx Name: mynginx Namespace: default Labels: app=mynginx Annotations: <none> Selector: app=mynginx Type: ClusterIP IP: 10.109.254.211 Port: 80-80 80/TCP TargetPort: 80/TCP Endpoints: 10.244.1.2:80 Session Affinity: None Events: <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
3>.手動刪除pod后k8s會自動幫咱們去創建一個pod，於此同時service也會自動關聯喲
[root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-l5xw2 1/1 Running 0 75m 10.244.1.2 node201.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl describe svc/mynginx Name: mynginx Namespace: default Labels: app=mynginx Annotations: <none> Selector: app=mynginx Type: ClusterIP IP: 10.109.254.211 Port: 80-80 80/TCP TargetPort: 80/TCP Endpoints: 10.244.1.2:80 Session Affinity: None Events: <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl delete pods mynginx-677d85dbd5-l5xw2 pod "mynginx-677d85dbd5-l5xw2" deleted [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mynginx-677d85dbd5-vk5p5 1/1 Running 0 8s 10.244.2.2 node202.yinzhengjie.org.cn <none> <none> [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]# kubectl describe svc/mynginx Name: mynginx Namespace: default Labels: app=mynginx Annotations: <none> Selector: app=mynginx Type: ClusterIP IP: 10.109.254.211 Port: 80-80 80/TCP TargetPort: 80/TCP Endpoints: 10.244.2.2:80 Session Affinity: None Events: <none> [root@master200.yinzhengjie.org.cn ~]#
四.API Server
我們知道API Server組件對K8S來說是非常重要的，如下圖所示，你得所有操作必須得經過API Server，有點類似於馮諾依曼體系中的總線角色。
API Server是中央管理實體，也是唯一與分布式存儲組件etcd直接對話的組件,它有以下特點:
服務器kubernetes API，工作節點在內部使用集群，kubectl在外部使用集群;
代理集群組件Kubernetes UI有一個叫做Dashboard組件，提供了很好的Web UI,后續我會分享如何部署的筆記;
允許操作對象的狀態，例如pod和service;
保存分布式存儲（etcd）中對象的狀態
Kubernetes API Server是一個以JSON為主要序列化模式的HTTP API，但是它也支持協議緩沖區(grpc)，主要用於集群內部通信。
我們知道顯式的時候可以以yaml格式顯式,那是因為API Server幫咱們將JSON格式轉換成yaml格式的;
我們給API Server提交請求可以是yaml格式，只不過API Server會自動將咱們提交的yaml格式的文件轉換成json格式喲;
除了支持JSON格式外，還支持Google公司自己研發的grpc,grpc是一款分布式高性能RPC框架,據說性能要比http協議的REST(REpresentational State Transfer)ful風格要好,因此httpd2.x(基於TCP的分布式協議)和httpd3.x(基於UDP的分布式協議)大量借鑒grpc的設計風格。
API Server把它的API接口中的資源分成多個邏輯組合:
API Group:
每個組合(通常都是一些相關的類型放在一起)就稱作一個API群組。
作用在於每個組可以獨立演進(迭代),比如改動某個組的API版本並不會影響到整個API Server,而且每個組還可以多版本共存;
REST（REpresentational State Transfer）是一種體系結構樣式，是一種用於Web開發的體系結構樣式,也是開發Web服務時通常使用的通信方法。
使用這種風格設計的系統和站點旨在實現快速性能、可靠性和擴展能力(以增加並輕松支持額外用戶);
為了實現這些目標，開發人員使用可重用的組件，這些組件可以在系統運行時進行管理和更新，而不會影響整個系統;
RESTful范式規范語法:
protocol://host(domain name):port/application context/version/resource/parameter
舉個例子:
https://haproxy.yinzhengjie.org.cn:8888/status/v1/users/{id}
五.資源對象的配置格式
API Server接收和返回的所有JSON對象都遵循同樣一個模式,它們都具有"kind"和"apiVersion"字段,用於標識對象所述的資源類型,API群組及相關的版本;
大多數的對象或列表類型的資源還需要具有三個嵌套的字段metadata,spec和status。
metadata字段:
為資源提供元數據信息，例如名稱,隸屬的名稱空間和標簽等;
spec字段:
用於定義用戶期望的狀態,不同的資源類型，其狀態的意義各不相同,例如pod資源最為核心的功能在於運行容器;
status字段:
記錄着活動對象的當前狀態信息，它由Kubernetes系統自行維護，對用戶來說為只讀字段;
我們可以通過"kubectl api-resources"命令獲取集群支持的所有資源類型。
[root@master200.yinzhengjie.org.cn ~]# kubectl api-resources NAME SHORTNAMES APIGROUP NAMESPACED KIND bindings true Binding componentstatuses cs false ComponentStatus configmaps cm true ConfigMap endpoints ep true Endpoints events ev true Event limitranges limits true LimitRange namespaces ns false Namespace nodes no false Node persistentvolumeclaims pvc true PersistentVolumeClaim persistentvolumes pv false PersistentVolume pods po true Pod podtemplates true PodTemplate replicationcontrollers rc true ReplicationController resourcequotas quota true ResourceQuota secrets true Secret serviceaccounts sa true ServiceAccount services svc true Service mutatingwebhookconfigurations admissionregistration.k8s.io false MutatingWebhookConfiguration validatingwebhookconfigurations admissionregistration.k8s.io false ValidatingWebhookConfiguration customresourcedefinitions crd,crds apiextensions.k8s.io false CustomResourceDefinition apiservices apiregistration.k8s.io false APIService controllerrevisions apps true ControllerRevision daemonsets ds apps true DaemonSet deployments deploy apps true Deployment replicasets rs apps true ReplicaSet statefulsets sts apps true StatefulSet tokenreviews authentication.k8s.io false TokenReview localsubjectaccessreviews authorization.k8s.io true LocalSubjectAccessReview selfsubjectaccessreviews authorization.k8s.io false SelfSubjectAccessReview selfsubjectrulesreviews authorization.k8s.io false SelfSubjectRulesReview subjectaccessreviews authorization.k8s.io false SubjectAccessReview horizontalpodautoscalers hpa autoscaling true HorizontalPodAutoscaler cronjobs cj batch true CronJob jobs batch true Job certificatesigningrequests csr certificates.k8s.io false CertificateSigningRequest leases coordination.k8s.io true Lease endpointslices discovery.k8s.io true EndpointSlice events ev events.k8s.io true Event ingresses ing extensions true Ingress ingresses ing networking.k8s.io true Ingress networkpolicies netpol networking.k8s.io true NetworkPolicy runtimeclasses node.k8s.io false RuntimeClass poddisruptionbudgets pdb policy true PodDisruptionBudget podsecuritypolicies psp policy false PodSecurityPolicy clusterrolebindings rbac.authorization.k8s.io false ClusterRoleBinding clusterroles rbac.authorization.k8s.io false ClusterRole rolebindings rbac.authorization.k8s.io true RoleBinding roles rbac.authorization.k8s.io true Role priorityclasses pc scheduling.k8s.io false PriorityClass csidrivers storage.k8s.io false CSIDriver csinodes storage.k8s.io false CSINode storageclasses sc storage.k8s.io false StorageClass volumeattachments storage.k8s.io false VolumeAttachment [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
[root@master200.yinzhengjie.org.cn ~]# kubectl get deploy mynginx -o yaml apiVersion: apps/v1 kind: Deployment metadata: annotations: deployment.kubernetes.io/revision: "1" creationTimestamp: "2020-02-04T22:14:32Z" generation: 3 labels: app: mynginx name: mynginx namespace: default resourceVersion: "39216" selfLink: /apis/apps/v1/namespaces/default/deployments/mynginx uid: 5c796fe6-03c9-40af-8ec6-0457a379e692 spec: progressDeadlineSeconds: 600 replicas: 2 revisionHistoryLimit: 10 selector: matchLabels: app: mynginx strategy: rollingUpdate: maxSurge: 25% maxUnavailable: 25% type: RollingUpdate template: metadata: creationTimestamp: null labels: app: mynginx spec: containers: - image: nginx:1.14-alpine imagePullPolicy: IfNotPresent name: nginx resources: {} terminationMessagePath: /dev/termination-log terminationMessagePolicy: File dnsPolicy: ClusterFirst restartPolicy: Always schedulerName: default-scheduler securityContext: {} terminationGracePeriodSeconds: 30 status: availableReplicas: 2 conditions: - lastTransitionTime: "2020-02-04T22:14:32Z" lastUpdateTime: "2020-02-04T22:14:40Z" message: ReplicaSet "mynginx-677d85dbd5" has successfully progressed. reason: NewReplicaSetAvailable status: "True" type: Progressing - lastTransitionTime: "2020-02-05T00:11:57Z" lastUpdateTime: "2020-02-05T00:11:57Z" message: Deployment has minimum availability. reason: MinimumReplicasAvailable status: "True" type: Available observedGeneration: 3 readyReplicas: 2 replicas: 2 updatedReplicas: 2 [root@master200.yinzhengjie.org.cn ~]# [root@master200.yinzhengjie.org.cn ~]#
六.和解循環(Reconciliation Loop)
和解循環的大致工作流程如下:
1>.客戶端向API Sever提交POST請求以創建對象
(1)通過JSON格式的body提交;
(2)YAML格式需要實現完成向JSON的轉換;
(3)對象配置信息保存於etcd中，其定義出的狀態也稱為"期望的狀態(spec)"
2>.控制器負責將其創建為kubernetes集群上的具體(活動)對象,並確保其當前狀態(status)與用戶定義的期望狀態相同.
(1)status由控制器自行維護,而spec則由用戶進行提交;
(2)活動對象在運行過程中因節點故障等原因可能會在某一時刻導致其status不在吻合於spec;
(3)控制器通過和解循環(Reconciliation Loop)不間斷地監控着相關對象的當前狀態,在對象的當前狀態發生改變時運行合適的操作讓其當前狀態無限接近與期望的狀態。