Container Service for Kubernetes:Associate an exclusive EIP with a pod

Automatically associate an EIP with a pod

Specify the ID of an EIP

You can associate an existing EIP with a pod by specifying the ID of the EIP. The pod annotations do not modify the configurations of the EIP. The annotations only associate the EIP with the specified pod.

Enable the EIP feature in a cluster that uses ack-extend-network-controller

Add annotations to create and associate an EIP with the specified pod.

You can add annotations to the configurations of a pod to create or associate an EIP with the pod. For more information about annotations, see the FAQ section of this topic.

1. Create an application. Then, create and associate an EIP with the specified pod.

   Deployments

   Create a Deployment based on the following sample code. The Deployment allocates an EIP to each pod. The bandwidth of each EIP is 5 Mbit/s.

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: example
     labels:
       app: example
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: example
     template:
       metadata:
         labels:
           app: example
         annotations:
           k8s.aliyun.com/pod-with-eip: "true"
           k8s.aliyun.com/eip-bandwidth: "5"
       spec:
         readinessGates:
         - conditionType: "k8s.aliyun.com/eip"
         containers:
         - name: example
           image: nginx

   After the pods are created, run the following command to query the podeips.alibabacloud.com resources that use the same names as the pods to track the EIP allocation information.

   kubectl get podeip -n <namespace> <podname>  -o yaml

   Expected results:

   apiVersion: alibabacloud.com/v1beta1
   kind: PodEIP
   metadata:
     creationTimestamp: "2023-12-15T04:25:37Z"
     finalizers:
     - podeip-controller.alibabacloud.com/finalizer
     generation: 1
     name: example-xxx
     namespace: default
     resourceVersion: "222800"
     uid: 43xxx-f1xx-4xxx-b3xx-969faxxx
   spec:
     allocationID: eip-2ze2qe8zsxxx
     allocationType:
       releaseStrategy: Follow
       type: Auto
   status:
     eipAddress: 39.102.XX.XX
     internetChargeType: PayByTraffic
     isp: BGP
     networkInterfaceID: eni-2zeagv8f3xxxx
     podLastSeen: "2023-12-15T05:18:47Z"
     privateIPAddress: 192.168.XX.XX
     resourceGroupID: rg-acfmwxxxxxsq
     status: InUse

   StatefulSets

   Create a StatefulSet based on the following sample code. The StatefulSet creates two pods and allocates an EIP to each pod. The EIPs are automatically released 10 minutes after the pods are deleted.

   apiVersion: apps/v1
   kind: StatefulSet
   metadata:
     name: example
     labels:
       app: example
   spec:
     serviceName: "example"
     replicas: 2
     selector:
       matchLabels:
         app: example
     template:
       metadata:
         labels:
           app: example
         annotations:
           k8s.aliyun.com/pod-with-eip: "true"
           k8s.aliyun.com/pod-eip-release-strategy: "10m"
       spec:
         containers:
         - name: example
           image: nginx

   After the pods are created, run the following command to query the podeips.alibabacloud.com resources that use the same names as the pods to track the EIP allocation information.

   kubectl get podeip -n <namespace> -o yaml

   Expected results:

   apiVersion: v1
   items:
   - apiVersion: alibabacloud.com/v1beta1
     kind: PodEIP
     metadata:
       creationTimestamp: "2023-12-15T03:28:01Z"
       finalizers
       - podeip-controller.alibabacloud.com/finalizer
       generation: 1
       name: example-0
       namespace: default
       resourceVersion: "227221"
       uid: 79954xx-17xx-4dxx-b7xx-15b84xxx
     spec:
       allocationID: eip-2ze08metxxx
       allocationType:
         releaseAfter: 10m
         releaseStrategy: TTL
         type: Auto
     status:
       eipAddress: 39.105.XX.XX
       internetChargeType: PayByTraffic
       isp: BGP
       networkInterfaceID: eni-2ze4tkg4xxx
       podLastSeen: "2023-12-15T05:31:34Z"
       privateIPAddress: 192.168.XX.XX
       resourceGroupID: rg-acfmwxxx
       status: InUse
   - apiVersion: alibabacloud.com/v1beta1
     kind: PodEIP
     metadata:
       creationTimestamp: "2023-12-15T03:28:03Z"
       finalizers:
       - podeip-controller.alibabacloud.com/finalizer
       generation: 1
       name: example-1
       namespace: default
       resourceVersion: "227222"
       uid: 1339xxxe7-97xx-46xx-9bxx-537690xxx
     spec:
       allocationID: eip-2zetwhffqxxx
       allocationType:
         releaseAfter: 10m
         releaseStrategy: TTL
         type: Auto
     status:
       eipAddress: 39.105.XX.XX
       internetChargeType: PayByTraffic
       isp: BGP
       networkInterfaceID: eni-2zeagv8f3wxxx
       podLastSeen: "2023-12-15T05:31:34Z"
       privateIPAddress: 192.168.XX.XX
       resourceGroupID: rg-acfmwqnwxxx
       status: InUse
   - apiVersion: alibabacloud.com/v1beta1
     kind: PodEIP
     metadata:
       creationTimestamp: "2023-12-15T04:25:37Z"
       finalizers:
       - podeip-controller.alibabacloud.com/finalizer
       generation: 1
       name: example-5bxxx-9xx
       namespace: default
       resourceVersion: "227220"
       uid: 43cdfxxx-f1xx-42xx-b3xx-969fxxx
     spec:
       allocationID: eip-2ze2qe8zsmnxxx
       allocationType:
         releaseStrategy: Follow
         type: Auto
     status:
       eipAddress: 39.102.XX.XX
       internetChargeType: PayByTraffic
       isp: BGP
       networkInterfaceID: eni-2zeagv8f3wxxx
       podLastSeen: "2023-12-15T05:31:34Z"
       privateIPAddress: 192.168.XX.XX
       publicIpAddressPoolID: pippool-2ze498cxxx
       resourceGroupID: rg-acfmwqnxxx
       status: InUse
   kind: List
   metadata:
     resourceVersion: ""

   After the pods of the StatefulSet are deleted, the EIPs are retained for 10 minutes and then released. If you create a pod with the same name during this period, the pod uses the same EIP.

2. Verify the configuration.

   After the status of a pod changes to Running, you can check the value of the k8s.aliyun.com/allocated-eipAddress annotation of the pod to identify the EIP used by the pod. Then, you can use the EIP to access the pod.

   

Enable the EIP feature in a cluster that uses Terway

Configure readiness gates for the pod

kind: Pod
...
spec:
  readinessGates:
  - conditionType: "k8s.aliyun.com/eip"
status:
  conditions:
  - lastProbeTime: "2022-12-12T03:45:48Z"
    lastTransitionTime: "2022-12-12T03:45:48Z"
    reason: Associate eip succeed
    status: "True"
    type: k8s.aliyun.com/eip
...

Configure an init container for the pod

You can configure an init container for the pod and use the init container to check whether the pod is associated with an EIP. The following sample code shows how to configure an init container.

apiVersion: v1
kind: Pod
metadata:
  name: example
  annotations:
    network.alibabacloud.com/pod-with-eip: "true"
spec:
  containers:
  - name: example
    image: busybox:1.28
    command: ['sh', '-c', 'echo The app is running! && sleep 3600']
  initContainers:
  - name: init
    image: busybox:1.28
    command: ['timeout', '-t' ,'60', 'sh','-c', "until grep -E '^k8s.aliyun.com\\/allocated-eipAddress=\\S?[0-9]+\\S?' /etc/podinfo/annotations; do echo waiting for annotations; sleep 2; done"]
    volumeMounts:
      - name: podinfo
        mountPath: /etc/podinfo
  volumes:
    - name: podinfo
      downwardAPI:
        items:
          - path: "labels"
            fieldRef:
              fieldPath: metadata.labels
          - path: "annotations"
            fieldRef:
              fieldPath: metadata.annotations