Serverless Kubernetes容器服务支持pod挂载弹性公网IP

近日，阿里云Serverless Kubernetes服务推出pod挂载弹性公网IP功能，此功能使某些serverless容器应用的部署和服务访问变得更加简单和便利。

无需创建VPC NAT网关即可让单个pod访问公网
无需创建service也可让单个pod暴露公网服务
可以更加灵活而且动态的绑定pod和eip

目前Serverless Kubernetes支持两种方法挂载eip，支持自动分配eip，或者指定eip实例进行绑定。

方法一：自动分配弹性公网IP

通过指定Annonation "k8s.aliyun.com/enable-eip"为"true"，serverless kubernetes服务会自动为此pod分配一个eip，并且绑定到pod上。

示例：

#cat nginx-enable-eip-pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  annotations:
    "k8s.aliyun.com/enable-eip": "true"
spec:
  containers:
  - image: registry-vpc.cn-hangzhou.aliyuncs.com/jovi/nginx:alpine
    imagePullPolicy: Always
    name: nginx
    ports:
    - containerPort: 80
      name: http
      protocol: TCP
  restartPolicy: OnFailure

创建pod：

#kubectl apply -f nginx-enable-eip-pod.yaml
pod "nginx" created

#kubectl get pod
nginx     1/1       Running   0         20s

查看pod的ip地址：

# kubectl describe pod
Name:         nginx
Namespace:    default
Node:         viking-c7d16b6c584544f65bfa4eba3a8b04d63/
Start Time:   Mon, 07 Jan 2019 13:19:47 +0800
Labels:       <none>
Annotations:  k8s.aliyun.com/allocated-eipAddress=47.96.67.132
              k8s.aliyun.com/allocated-eipInstanceId=eip-bp1wtbt7vp18tgu5g7rb2
              k8s.aliyun.com/enable-eip=true
              kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{"k8s.aliyun.com/enable-eip":"true"},"name":"nginx","namespace":"default"},"spec":{"container...
              kubernetes.io/limit-ranger=LimitRanger plugin set: cpu, memory request for container nginx
Status:       Running
IP:           10.1.89.103
Containers:
  nginx:
    Container ID:   eci://779380281b08b325b4b7a1b66c4cb9e706985b25cde0c36345af93a308745b95
    Image:          registry-vpc.cn-hangzhou.aliyuncs.com/jovi/nginx:alpine
    Image ID:
    Port:           80/TCP
    State:          Running
      Started:      Mon, 07 Jan 2019 13:19:47 +0800
    Ready:          True
    Restart Count:  0
    Requests:
      cpu:        1
      memory:     2Gi
    Environment:  <none>
    ...
    
# kubectl describe pod|grep allocated-eipAddress
Annotations:  k8s.aliyun.com/allocated-eipAddress=47.96.67.132

我们可以看到在pod的Annotations中显示了已分配的eip，通过此eip可直接访问pod。

# curl 47.96.67.132
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
...

因为此方式中eip为动态分配，其生命周期与pod相同，当pod被删除时，动态分配的eip也会被一同删除。

方法二：指定弹性公网IP实例id

首先用户需要在eip控制台购买弹性公网eip。

通过指定pod的Annonation "k8s.aliyun.com/eipInstanceId"为eip实例id，如下：

# cat nginx-eipid-pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  annotations:
    "k8s.aliyun.com/eipInstanceId": "eip-bp19trewkig3i9pnek99i"
spec:
  containers:
  - image: registry-vpc.cn-hangzhou.aliyuncs.com/jovi/nginx:alpine
    imagePullPolicy: Always
    name: nginx
    ports:
    - containerPort: 80
      name: http
      protocol: TCP
  restartPolicy: OnFailure

创建pod

# kubectl apply -f  nginx-eipid-pod.yaml
pod "nginx" created

# kubectl get pod
NAME      READY     STATUS    RESTARTS   AGE
nginx     1/1       Running   0         20s

通过eip访问pod：

# curl 47.111.20.92
<!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>
...

此种方式种当pod被删除时，pod和eip解除绑定。pod重新创建时eip则会重新被绑定。

快速试用Serverless Kubernetes

欢迎登录容器服务控制台，公测期间免费使用，https://cs.console.aliyun.com/#/k8s

如在使用中有任何问题，欢迎扫码加入Serverless K8s钉钉群进行讨论