container-guide/DOCUMENTS/mapping-external-services.md

mapping-external-services.md
---------------------------------------------------------
```
@version    180807:1
@author     zhangxuhong <zhangxuhong@xitu.io>
```

Name
----

    mapping-external-services - 映射外部服务.

    
Table of Contents
-----------------

* [Name](#name)
* [Reference 参考文档](#reference)



Reference 参考文档
------------------

* [https://cloudplatform.googleblog.com/2018/05/Kubernetes-best-practices-mapping-external-services.html](https://cloudplatform.googleblog.com/2018/05/Kubernetes-best-practices-mapping-external-services.html)
* [ClusterIP和NodePort的区别](https://medium.com/google-cloud/kubernetes-nodeport-vs-loadbalancer-vs-ingress-when-should-i-use-what-922f010849e0)

case
----

有的时候我们要访问 kubernetes 集群外部的服务.
这些服务可能是没来得及迁移到集群里面的, 或者第三方的, 或者是托管的数据库.
因此便有了映射外部服务的场景.


method
------

- 映射外部IP和端口

- service

```
kind: Service
apiVersion: v1
metadata:
  name: mongo
  labels:
    name: mongo
    role: proxy
    pl: cpp 
    application: mongo
    version: 16.03
    division: infrastructure
Spec:
  type: ClusterIP
  ports:
  - port: 27017
    targetPort: 27017
```

- endpoints

```
kind: Endpoints
apiVersion: v1
metadata:
  name: mongo
  labels:
    name: mongo
    role: proxy
    pl: cpp 
    application: mongo
    version: 16.03
    division: infrastructure
subsets:
  - addresses:
    - ip: 192.168.0.203
  ports:
    - port: 27017
```


- 映射外部URI

- service

```
kind: Service
apiVersion: v1
metadata:
  name: mongo
  labels:
    name: mongo
    role: proxy
    pl: cpp 
    application: mongo
    version: 16.03
    division: infrastructure
spec:
 type: ExternalName
 externalName: mongodb01v.lobj.juejin.id
```


- 映射外部IP并转发端口


- service

```
kind: Service
apiVersion: v1
metadata:
  name: mongo
  labels:
    name: mongo
    role: proxy
    pl: cpp 
    application: mongo
    version: 16.03
    division: infrastructure
Spec:
  type: ClusterIP
  ports:
  - port: 27017
    targetPort: 7000
```

- endpoints

```
kind: Endpoints
apiVersion: v1
metadata:
  name: mongo
  labels:
    name: mongo
    role: proxy
    pl: cpp 
    application: mongo
    version: 16.03
    division: infrastructure
subsets:
  - addresses:
    - ip: 192.168.0.203
  ports:
    - port: 7000
```