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28.kubernetes(k8s)笔记 CRD

CustomResourceDefinition简介：
在 Kubernetes 中一切都可视为资源，Kubernetes 1.7 之后增加了对 CRD 自定义资源二次开发能力来扩展 Kubernetes API，通过 CRD 我们可以向 Kubernetes API 中增加新资源类型，而不需要修改 Kubernetes 源码来创建自定义的 API server，该功能大大提高了 Kubernetes 的扩展能力。
当你创建一个新的CustomResourceDefinition (CRD)时，Kubernetes API服务器将为你指定的每个版本创建一个新的RESTful资源路径，我们可以根据该api路径来创建一些我们自己定义的类型资源。CRD可以是命名空间的，也可以是集群范围的，由CRD的作用域(scpoe)字段中所指定的，与现有的内置对象一样，删除名称空间将删除该名称空间中的所有自定义对象。customresourcedefinition本身没有名称空间，所有名称空间都可以使用。

  • 目前扩展Kubernetes API的常用方式有3种:
  • 使用CRD(CustomResourceDefinitions)自定义资源类型
  • 开发自定义的APIServer并聚合至主API Server
  • 及定制扩展API Server源码。这其中，CRD最为易用但限制颇多，自定义API Server更富于弹性但代码工作量偏大，而仅在必须添加新的核心类型才能确保专用的Kberneves集群功能正常，才应该定制系统源码
  • CRD-->CRT-->CR
    其中CRD与CRT一般由开发或服务供应商提供
    CRD只是定义一个类型Kind，但实际把kind运行起来CR需要有Controller来对资源进行控制，所有只有定义CRD定义没有并没有实际意义，当然也可以通过定义现在kind来运行，比如deployment 通过定义 RC来运行
配置规范
apiVersion: apiextensions.k8s.io/v1 #API群组和版本 kind: CustomResourceDefinition #资源类别 metadata: -name#资源名称 spec: conversion #定义不同版本间的格式转换方式 strategy # 不同版本间的自定义资源转换策略，有None和webhook两种取值 webhook <0bject>#如何调用用于进行格式转换的webhook group #资源所属的API群组 names # 自定义资源的类型，即该CRD创建资源规范时使用的kind categories # 启用status子资源，为资源生成/status端点
  • 可以查看之前部署Calico创建的自定义CRD
[root@k8s-master ~]# kubectl api-resources#查看所有资源类型 NAMESHORTNAMESAPIGROUPNAMESPACEDKIND ... bgpconfigurationscrd.projectcalico.orgfalseBGPConfiguration bgppeerscrd.projectcalico.orgfalseBGPPeer blockaffinitiescrd.projectcalico.orgfalseBlockAffinity clusterinformationscrd.projectcalico.orgfalseClusterInformation felixconfigurationscrd.projectcalico.orgfalseFelixConfiguration globalnetworkpoliciescrd.projectcalico.orgfalseGlobalNetworkPolicy globalnetworksetscrd.projectcalico.orgfalseGlobalNetworkSet hostendpointscrd.projectcalico.orgfalseHostEndpoint ipamblockscrd.projectcalico.orgfalseIPAMBlock ipamconfigscrd.projectcalico.orgfalseIPAMConfig ipamhandlescrd.projectcalico.orgfalseIPAMHandle ippoolscrd.projectcalico.orgfalseIPPool kubecontrollersconfigurationscrd.projectcalico.orgfalseKubeControllersConfiguration networkpoliciescrd.projectcalico.orgtrueNetworkPolicy networksetscrd.projectcalico.orgtrueNetworkSet

  • 【28.kubernetes(k8s)笔记 CRD】查看calico的yaml文件可以看到里面很多CRD的定义
    [root@k8s-master plugin]# vim calico.yaml ... --- apiVersion: apiextensions.k8s.io/v1 kind: CustomResourceDefinition metadata: name: ippools.crd.projectcalico.org spec: ...... ...[root@k8s-master plugin]# kubectl get CustomResourceDefinition NAMECREATED AT bgpconfigurations.crd.projectcalico.org2021-08-29T14:33:24Z bgppeers.crd.projectcalico.org2021-08-29T14:33:24Z blockaffinities.crd.projectcalico.org2021-08-29T14:33:24Z clusterinformations.crd.projectcalico.org2021-08-29T14:33:24Z felixconfigurations.crd.projectcalico.org2021-08-29T14:33:24Z globalnetworkpolicies.crd.projectcalico.org2021-08-29T14:33:24Z globalnetworksets.crd.projectcalico.org2021-08-29T14:33:24Z hostendpoints.crd.projectcalico.org2021-08-29T14:33:24Z ipamblocks.crd.projectcalico.org2021-08-29T14:33:24Z ipamconfigs.crd.projectcalico.org2021-08-29T14:33:24Z ipamhandles.crd.projectcalico.org2021-08-29T14:33:24Z ippools.crd.projectcalico.org2021-08-29T14:33:24Z kubecontrollersconfigurations.crd.projectcalico.org2021-08-29T14:33:24Z networkpolicies.crd.projectcalico.org2021-08-29T14:33:24Z networksets.crd.projectcalico.org2021-08-29T14:33:25Z

    示例1: 创建自定义CRD
    [root@k8s-master crd]# cat crd-v1-user.yaml apiVersion: apiextensions.k8s.io/v1 kind: CustomResourceDefinition metadata: name: users.auth.ilinux.io spec: group: auth.ilinux.io names: kind: User plural: users singular: user shortNames: - u scope: Namespaced#名称空间级别 versions: - served: true storage: true name: v1alpha1#版本号 schema: openAPIV3Schema: type: object#对字段做限制 properties: spec: type: object properties: userID: type: integer#整形 minimum: 1 maximum: 65535 groups : type: array#列表 items: type: string email: type: string password: type: string format: password required: ["userID","groups"] [root@k8s-master crd]# kubectl apply -f crd-v1-user.yaml [root@k8s-master crd]# kubectl api-resources NAMESHORTNAMESAPIGROUPNAMESPACEDKIND bindingstrueBinding ... usersuauth.ilinux.iotrueUser

  • 创造自定义CRD类型
    [root@k8s-master crd]# cat user-cr-demo.yaml apiVersion: auth.ilinux.io/v1alpha1 kind: User metadata: name: admin namespace: default spec: userID: 1 email: test@test.com groups: - superusers - adminstrators password: ikubernetes.io[root@k8s-master crd]# kubectl apply -f user-cr-demo.yaml user.auth.ilinux.io/admin created[root@k8s-master crd]# kubectl get User NAMEAGE admin14s[root@k8s-master ~]# kubectl describe User admin Name:admin Namespace:default Labels: Annotations: API Version:auth.ilinux.io/v1alpha1 Kind:User Metadata: Creation Timestamp:2021-09-10T14:51:53Z Generation:1 Managed Fields: API Version:auth.ilinux.io/v1alpha1 Fields Type:FieldsV1 fieldsV1: f:metadata: f:annotations: .: f:kubectl.kubernetes.io/last-applied-configuration: f:spec: .: f:email: f:groups: f:password: f:userID: Manager:kubectl-client-side-apply Operation:Update Time:2021-09-10T14:51:53Z Resource Version:2583010 Self Link:/apis/auth.ilinux.io/v1alpha1/namespaces/default/users/admin UID:5af89454-e067-4f30-83b7-cc2ad82e3526 Spec: Email:test@test.com Groups: superusers adminstrators Password:ikubernetes.io User ID:1 Events:

  • 以上定义的kind资源 没Controller并不能运行成实际对象，Controller的开发需要开发来完成
示例2: etcd Operator 部署 (该项目已不在维护)
28.kubernetes(k8s)笔记 CRD
文章图片

  • Operator 项目地址:
    https://github.com/operator-f...
    https://github.com/coreos/etc...
    https://github.com/coreos/etc...
    1. 先安装RBAC 再安装etcd operator 再部署创建etcd集群
      [root@k8s-master etcd-operator]# example/rbac/create_role.sh Creating role with ROLE_NAME=etcd-operator, NAMESPACE=default Warning: rbac.authorization.k8s.io/v1beta1 ClusterRole is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRole clusterrole.rbac.authorization.k8s.io/etcd-operator created Creating role binding with ROLE_NAME=etcd-operator, ROLE_BINDING_NAME=etcd-operator, NAMESPACE=default Warning: rbac.authorization.k8s.io/v1beta1 ClusterRoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRoleBinding clusterrolebinding.rbac.authorization.k8s.io/etcd-operator created[root@k8s-master etcd-operator]# kubectl create -f example/deployment.yaml error: unable to recognize "example/deployment.yaml": no matches for kind "Deployment" in version "extensions/v1beta1" #deployment版本太老修改example/deployment.yaml [root@k8s-master etcd-operator]# cat example/deployment.yaml apiVersion: apps/v1#版本 kind: Deployment metadata: name: etcd-operator spec: replicas: 1 selector:#添加字段 matchLabels: name: etcd-operator template: metadata: labels: name: etcd-operator spec: containers: - name: etcd-operator image: quay.io/coreos/etcd-operator:v0.9.4 command: - etcd-operator # Uncomment to act for resources in all namespaces. More information in doc/user/clusterwide.md #- -cluster-wide env: - name: MY_POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace - name: MY_POD_NAME valueFrom: fieldRef: fieldPath: metadata.name[root@k8s-master etcd-operator]# kubectl create -f example/deployment.yaml deployment.apps/etcd-operator created [root@k8s-master etcd-operator]# [root@k8s-master etcd-operator]# kubectl api-resources ... etcdclustersetcdetcd.database.coreos.comtrueEtcdCluster

    1. 部署创建etcd集群
    [root@k8s-master etcd-operator]# cat example/example-etcd-cluster.yaml apiVersion: "etcd.database.coreos.com/v1beta2" kind: "EtcdCluster" metadata: name: "example-etcd-cluster" ## Adding this annotation make this cluster managed by clusterwide operators ## namespaced operators ignore it # annotations: #etcd.database.coreos.com/scope: clusterwide spec: size: 3#集群数理 version: "3.2.13" [root@k8s-master etcd-operator]# kubectl apply -fexample/example-etcd-cluster.yaml etcdcluster.etcd.database.coreos.com/example-etcd-cluster created[root@k8s-master etcd-operator]# kubectl get pod -o wide NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES etcd-operator-646cbffdb6-brbn61/1Running012m192.168.51.58k8s-node3 example-etcd-cluster-nc8pdgjrjr1/1Running03m3s192.168.51.59k8s-node3

  • 后面在加一个SVC就可以使用了

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