目录
一、CRD 扩展 Kubernetes 集群
1.什么是 CRD
$kubectl get crd
NAME CREATED AT
apps.app.my.cn 2022-09-25T07:02:47Z
microservices.app.my.cn 2022-09-25T07:02:47Z
2.CRD 能做什么
(1)微服务管理总览
(2)创建 Yaml 配置
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
creationTimestamp: null
labels:
controller-tools.k8s.io: "1.0"
# 名称必须与下面的spec字段匹配,格式为: <plural>.<group>
name: apps.app.o0w0o.cn
spec:
# 用于REST API的组名称: /apis/<group>/<version>
group: app.o0w0o.cn
names:
# kind字段使用驼峰命名规则. 资源清单使用如此
kind: App
# URL中使用的复数名称: /apis/<group>/<version>/<plural>
plural: apps
# 指定crd资源作用范围在命名空间或集群
scope: Namespaced
# 自定义资源的子资源的描述
subresources:
# 启用状态子资源
status: {}
# 验证机制
validation:
# openAPIV3Schema is the schema for validating custom objects.
openAPIV3Schema:
properties:
...
(3)自定义 Controller 逻辑
func (r *ReconcileApp) Reconcile(request reconcile.Request) (reconcile.Result, error) {
...
// 状态 App 同步
if err := r.syncAppStatus(instance); err != nil {
log.Info("Sync App error", err)
return reconcile.Result{}, err
}
// 协调资源 MicroService
if err := r.reconcileMicroService(request, instance); err != nil {
log.Info("Creating MicroService error", err)
return reconcile.Result{}, err
}
...
}
func (r *ReconcileMicroService) Reconcile(request reconcile.Request) (reconcile.Result, error) {
...
// 同步 MicroService 状态
if err := r.syncMicroServiceStatus(instance); err != nil {
log.Info("Sync MicroServiceStatus error", err)
return reconcile.Result{}, err
}
// 协调实例
if err := r.reconcileInstance(instance); err != nil {
log.Info("Reconcile Instance Versions error", err)
return reconcile.Result{}, err
}
// 协调负载均衡器
if err := r.reconcileLoadBalance(instance); err != nil {
log.Info("Reconcile LoadBalance error", err)
return reconcile.Result{}, err
}
...
}
二、CRD 字段校验
1.校验方式
2.举例
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
# name must match the spec fields below, and be in the form: <plural>.<group>
name: kubernetesclusters.ecs.yun.com
spec:
# group name to use for REST API: /apis/<group>/<version>
group: ecs.yun.com
# list of versions supported by this CustomResourceDefinition
versions:
- name: v1
# Each version can be enabled/disabled by Served flag.
served: true
# One and only one version must be marked as the storage version.
storage: true
# either Namespaced or Cluster
scope: Namespaced
names:
# plural name to be used in the URL: /apis/<group>/<version>/<plural>
plural: kubernetesclusters
# singular name to be used as an alias on the CLI and for display
singular: kubernetescluster
# kind is normally the CamelCased singular type. Your resource manifests use this.
kind: KubernetesCluster
# listKind
listKind: KubernetesClusterList
# shortNames allow shorter string to match your resource on the CLI
shortNames:
- ecs
#CRD 对象
apiVersion: ecs.yun.com/v1
kind: KubernetesCluster
metadata:
name: test-cluster
spec:
clusterType: kubernetes
serviceCIDR: ''
masterList:
- ip: 192.168.1.10
nodeList:
- ip: 192.168.1.11
privateSSHKey: ''
scaleUp: 0
scaleDown: 0
3.API的常用方式
- 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
- 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
(1)配置
apiVersion: apiextensions.k8s.io/v1 #API群组和版本
kind: CustomResourceDefinition #资源类别
metadata:
-name <string> #资源名称
spec:
conversion <object> #定义不同版本间的格式转换方式
strategy <string># 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 <string>#资源所属的API群组
names <object># 自定义资源的类型,即该CRD创建资源规范时使用的kind
categories <[]string>#资源所属的类别编目,例如"kubectl get all"中的all
kind <string> #kind名称,必选字段
listKind <string> #资源列表名称,默认为"`kind`List"
plural <string> #复数,用于API路径`/apis/<group>/<version>/. . ./<plural>"
shortNames <[string>#该资源的kind的缩写格式
singular <string>#资源kind的单数形式,必须使用全小写字母,默认为小写的kind名称
preserveUnknownFields <boolean> #预留的非知名字段,kind等都是知名的预留字段
scope <string> #作用域,可用值为Cluster和Namespaced
versions <[]object>#版本号定义
additionalPrinterColumns <[]0bject> #需要返回的额外信息
name <string> #形如vM[alphaN|betaN]格式的版本名称,例如v1或vlalpha2等
schema <object> #该资源的数据格式(schema)定义,必选字段
openAPIV3Schema <object> #用于校验字段的schema对象,格式请参考相关手册
served <boolean> #是否允许通过RESTful API调度该版本,必选字段
storage <boolean> #将自定义资源存储于etcd中时是不是使用该版本
subresources <0bject>#子资源定义
scale <0bject># 启用scale子资源,通过autoscaling/v1.Scale发送负荷
status <map[string]># 启用status子资源,为资源生成/status端点
(2)查看文件
calico的yaml文件
[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
NAME CREATED AT
bgpconfigurations.crd.projectcalico.org 2022-08-25T14:33:24Z
bgppeers.crd.projectcalico.org 2022-08-25T14:33:24Z
blockaffinities.crd.projectcalico.org 2022-08-25T14:33:24Z
clusterinformations.crd.projectcalico.org 2022-08-25T14:33:24Z
felixconfigurations.crd.projectcalico.org 2022-08-25T14:33:24Z
globalnetworkpolicies.crd.projectcalico.org 2022-08-25T14:33:24Z
globalnetworksets.crd.projectcalico.org 2022-08-25T14:33:24Z
hostendpoints.crd.projectcalico.org 2022-08-25T14:33:24Z
ipamblocks.crd.projectcalico.org 2022-08-25T14:33:24Z
ipamconfigs.crd.projectcalico.org 2022-08-25T14:33:24Z
ipamhandles.crd.projectcalico.org 2022-08-25T14:33:24Z
ippools.crd.projectcalico.org 2022-08-25T14:33:24Z
kubecontrollersconfigurations.crd.projectcalico.org 2022-08-25T14:33:24Z
networkpolicies.crd.projectcalico.org 2022-08-25T14:33:24Z
networksets.crd.projectcalico.org 2022-08-25T14:33:24Z
(3)自定义CRD模型
[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
NAME AGE
admin 14s
[root@k8s-master ~]# kubectl describe User admin
Name: admin
Namespace: default
Labels: <none>
Annotations: <none>
API Version: auth.ilinux.io/v1alpha1
Kind: User
Metadata:
Creation Timestamp: 2022-09-25T14:51:53Z
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: 2022-09-25T14:51:53Z
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: <none>