kubernetes-handbook/concepts/apiservice.md

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2017-12-14 19:35:20 +08:00
# APIService
APIService是用来表示一个特定的`GroupVersion`的中的server它的结构定义位于代码`staging/src/k8s.io/kube-aggregator/pkg/apis/apiregistration/types.go`中。
下面是一个APIService的示例配置
```yaml
apiVersion: apiregistration.k8s.io/v1beta1
kind: APIService
metadata:
name: v1alpha1.custom-metrics.metrics.k8s.io
spec:
insecureSkipTLSVerify: true
group: custom-metrics.metrics.k8s.io
groupPriorityMinimum: 1000
versionPriority: 5
service:
name: api
namespace: custom-metrics
version: v1alpha1
```
## APIService详解
使用`apiregistration.k8s.io/v1beta1` 版本的APIService在metadata.name中定义该API的名字。
使用上面的yaml的创建`v1alpha1.custom-metrics.metrics.k8s.io` APIService。
- `insecureSkipTLSVerify `当与该服务通信时禁用TLS证书认证。强加建议不要设置这个参数默认为 false。应该使用CABundle代替。
- `service`与该APIService通信时引用的service其中要注明service的名字和所属的namespace如果为空的话则所有的服务都会该API groupversion将在本地443端口处理所有通信。
- `groupPriorityMinimum`该组API的处理优先级主要排序是基于`groupPriorityMinimum`该数字越大表明优先级越高客户端就会与其通信处理请求。次要排序是基于字母表顺序例如v1.bar比v1.foo的优先级更高。
- `versionPriority`VersionPriority控制其组内的API版本的顺序。必须大于零。主要排序基于VersionPriority从最高到最低20大于10排序。次要排序是基于对象名称的字母比较。 v1.foo在v1.bar之前由于它们都是在一个组内因此数字可能很小一般都小于10。
查看我们使用上面的yaml文件创建的APIService。
```bash
kubectl get apiservice v1alpha1.custom-metrics.metrics.k8s.io -o yaml
```
```yaml
apiVersion: apiregistration.k8s.io/v1beta1
kind: APIService
metadata:
creationTimestamp: 2017-12-14T08:27:35Z
name: v1alpha1.custom-metrics.metrics.k8s.io
resourceVersion: "35194598"
selfLink: /apis/apiregistration.k8s.io/v1beta1/apiservices/v1alpha1.custom-metrics.metrics.k8s.io
uid: a31a3412-e0a8-11e7-9fa4-f4e9d49f8ed0
spec:
caBundle: null
group: custom-metrics.metrics.k8s.io
groupPriorityMinimum: 1000
insecureSkipTLSVerify: true
service:
name: api
namespace: custom-metrics
version: v1alpha1
versionPriority: 5
status:
conditions:
- lastTransitionTime: 2017-12-14T08:27:38Z
message: all checks passed
reason: Passed
status: "True"
type: Available
```
## 查看集群支持的APISerivce
作为Kubernetes中的一种资源对象可以使用`kubectl get apiservice`来查看。
例如查看集群中所有的APIService
```bash
$ kubectl get apiservice
NAME AGE
v1. 2d
v1.authentication.k8s.io 2d
v1.authorization.k8s.io 2d
v1.autoscaling 2d
v1.batch 2d
v1.monitoring.coreos.com 1d
v1.networking.k8s.io 2d
v1.rbac.authorization.k8s.io 2d
v1.storage.k8s.io 2d
v1alpha1.custom-metrics.metrics.k8s.io 2h
v1beta1.apiextensions.k8s.io 2d
v1beta1.apps 2d
v1beta1.authentication.k8s.io 2d
v1beta1.authorization.k8s.io 2d
v1beta1.batch 2d
v1beta1.certificates.k8s.io 2d
v1beta1.extensions 2d
v1beta1.policy 2d
v1beta1.rbac.authorization.k8s.io 2d
v1beta1.storage.k8s.io 2d
v1beta2.apps 2d
v2beta1.autoscaling 2d
```
另外查看当前kubernetes集群支持的API版本还可以使用`kubectl api-version`
```bash
$ kubectl api-versions
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1beta1
apps/v1beta1
apps/v1beta2
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
custom-metrics.metrics.k8s.io/v1alpha1
extensions/v1beta1
monitoring.coreos.com/v1
networking.k8s.io/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1
```
## 参考
[API Conventions](https://github.com/kubernetes/community/blob/master/contributors/devel/api-conventions.md#resources)
[Kuberentes1.8 reference doc](https://kubernetes.io/docs/api-reference/v1.8/#apiservicespec-v1beta1-apiregistration)