Container Service for Kubernetes:Attach an independent EIP to a pod

Create and associate an EIP with a specified pod using an annotation

You can create or associate an EIP with a pod by specifying an annotation in the pod. For more information about annotations, see the FAQ section in this topic.

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

   Deployment

   Use the following example to create a deployment. An EIP instance with a bandwidth of 5 Mbit/s is automatically allocated to each pod.

   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 pod is created, you can query the podeips.alibabacloud.com resource that has the same name as the pod to track information about the allocated EIP.

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

   Expected output:

   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

   Statefulset

   Use the following example to create a StatefulSet resource. Two pods are created, and an EIP instance is automatically allocated to each pod. The release policy is set to delete the PodEIP 10 minutes after the pod is 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 pod is created, you can retrieve the allocated EIP information from the podeips.alibabacloud.com resource that has the same name as the pod.

   kubectl get podeip -n <namespace> -o yaml

   Expected output:

   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 a pod from a stateful application is deleted, its corresponding PodEIP custom resource (CR) is retained for 10 minutes before being deleted. If a pod with the same name is created during this time, it will reuse the EIP.

2. Verify the configuration.

   After the pod enters the Running state, you can check the value of the k8s.aliyun.com/allocated-eipAddress annotation in the pod to view its associated EIP address. You can then access the pod using this EIP.

   

1. Configure Terway to support the EIP feature.

   1. Modify the Terway ConfigMap.

      kubectl edit cm eni-config -n kube-system

   2. Add the following content to eni_conf.

      "enable_eip_pool": "true"

      Note

      If you want to forcibly detach a previous instance when you specify an EIP, you must also add the "allow_eip_rob": "true" parameter to eni_conf.

   3. After you modify the file, press the Esc key, enter :wq!, and then press the Enter key to save the modified configuration file and exit edit mode.

   4. Recreate the Terway instance.

      kubectl delete pod -n kube-system -l app=terway-eniip # If you installed the terway-eni component, replace terway-eniip with terway-eni.

2. Use an annotation to create and associate an EIP with a pod.

   You can create or associate an EIP with a pod by specifying an annotation in the pod. For more information about EIP limits, see Limits.

   Configure annotations for different scenarios as follows:

   Automatic EIP allocation scenario

   Add the following annotations to automatically allocate an EIP to a pod and specify the bandwidth of the EIP.

   • k8s.aliyun.com/pod-with-eip: "true": Allocates an independent public EIP to the target pod.

   • k8s.aliyun.com/eip-bandwidth: "5": Specifies the bandwidth of the EIP. The default bandwidth is 5 Mbit/s, which is the same as the default value for EIPs.

   The following code provides a sample YAML file.

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx-deployment-basic
     labels:
       app: nginx
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: nginx
     template:
       metadata:
         annotations:
           network.alibabacloud.com/pod-with-eip: "true" # Automatically allocate a public EIP address to the Nginx container.
           network.alibabacloud.com/eip-bandwidth: "5"   # Specify the bandwidth of the EIP. The default bandwidth is 5 Mbit/s, which is consistent with the default value for EIPs.
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx

   Specify EIP scenario

   Important

   • A single EIP cannot be associated with multiple pods. Therefore, this scenario is not applicable to deployments and StatefulSets.

   • By default, if the EIP is already attached to an instance, the EIP cannot be attached to the pod. If you want to detach the EIP from the previous instance before you attach it to the new one, you must configure "allow_eip_rob": "true" in the ConfigMap as described in the preceding step.

   • You can specify an EIP instance ID only for single-replica instances. For example, a deployment cannot have more than one replica.

   Add the following annotation to specify an EIP instance ID for a pod:

   k8s.aliyun.com/pod-eip-instanceid: "<youreipInstanceId>"

3. Verify the configuration.

   After the pod enters the Running state, you can check the value of the network.alibabacloud.com/allocated-eipAddress annotation in the pod to view its associated EIP address. You can then access the pod using this EIP.