Configuring an EIP for a Pod

Application Scenarios

In Cloud Native Network 2.0, pods use VPC ENIs or sub-ENIs for networking. You can directly bind EIPs to pods.

To associate an EIP with a pod, simply set the value of the yangtse.io/pod-with-eip annotation to true when creating the pod. Then, the EIP will be automatically allocated and bound to the pod.

Prerequisites

A CCE Turbo cluster is available and the cluster version meets the requirements listed in the following table.

Notes and Constraints

• To access a pod bound with an EIP from the Internet, add security group rules to allow the target request traffic.
• Only one EIP can be bound to a pod.
• Configure the EIP-related annotation when creating a pod. After the pod is created, the annotations related to the EIP cannot be modified.
• Do not perform operations on the EIP associated with a pod through the EIP console or API. Otherwise, the EIP may malfunction. The operations include changing the EIP name, deleting, unbinding, or binding the EIP, and changing the billing mode of the EIP.
• After an automatically allocated EIP is manually deleted, the network malfunctions. In this case, rebuild the pod.

Allocating an EIP with a Pod

If you set the pod-with-eip annotation to true when creating a pod, an EIP will be automatically allocated and bound to the pod.

• CCE will automatically add cluster ID, namespace, and pod name labels to an EIP that has been allocated automatically.
• If a pod is created with an automatically allocated EIP, deleting the pod will also delete the EIP.

The following uses a Deployment named nginx as an example. For details about annotations, see Table 2.

• For an automatically allocated EIP with a dedicated bandwidth when you create a Deployment, you do not need to specify the bandwidth ID. The following shows an example:

  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: nginx
  spec:
    replicas: 3
    selector:
      matchLabels:
        app: nginx
    template:
      metadata:
        labels:
          app: nginx
        annotations:
          yangtse.io/pod-with-eip: "true"  # An EIP will be automatically allocated when the pod is created.
          yangtse.io/eip-bandwidth-size: "5"  # EIP bandwidth
          yangtse.io/eip-network-type: 5_bgp  # EIP type
          yangtse.io/eip-charge-mode: bandwidth  # EIP billing mode
          yangtse.io/eip-bandwidth-name: <eip_bandwidth_name>  # EIP bandwidth name
      spec:
        containers:
          - name: container-0
            image: nginx:alpine
            resources:
              limits:
                cpu: 100m
                memory: 200Mi
              requests:
                cpu: 100m
                memory: 200Mi
        imagePullSecrets:
          - name: default-secret

  Table 1 Annotations of an EIP with a dedicated bandwidth

  Annotation	Mandatory	Default Value	Description	Value Range
  yangtse.io/pod-with-eip	Yes	false	Whether to allocate an EIP with a pod and bind the EIP to the pod	false or true
  yangtse.io/eip-bandwidth-size	No	5	Bandwidth, in Mbit/s	The value range varies depending on the region and bandwidth billing mode. For details, see the EIP console.
  yangtse.io/eip-network-type	No	5_bgp	EIP type	The type varies depending on the region. For details, see on the EIP console.
  yangtse.io/eip-charge-mode	No	None	Billed by traffic or bandwidth You are advised to configure this parameter. If this parameter is left blank, no billing mode is specified. In this case, the default value of the EIP API in the region is used.	bandwidth: billed by bandwidth traffic: billed by traffic
  yangtse.io/eip-bandwidth-name	No	Pod name	Bandwidth name	Enter 1 to 64 characters. Only letters, digits, hyphens (-), underscores (_), and periods (.) are allowed. Minimum length: 1 character Maximum length: 64 characters

• For an automatically allocated EIP with a shared bandwidth when you create a Deployment, you are required to specify the bandwidth ID. The following shows an example:

  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: nginx
  spec:
    replicas: 3
    selector:
      matchLabels:
        app: nginx
    template:
      metadata:
        labels:
          app: nginx
        annotations:
          yangtse.io/pod-with-eip: "true"  # An EIP will be automatically allocated when the pod is created.
          yangtse.io/eip-network-type: 5_bgp  # EIP type
          yangtse.io/eip-bandwidth-id: <eip_bandwidth_id>  # Shared bandwidth ID of the EIP
      spec:
        containers:
          - name: container-0
            image: nginx:alpine
            resources:
              limits:
                cpu: 100m
                memory: 200Mi
              requests:
                cpu: 100m
                memory: 200Mi
        imagePullSecrets:
          - name: default-secret

  Table 2 Annotations of an EIP with a shared bandwidth

  Annotation	Mandatory	Default Value	Description	Value Range
  yangtse.io/pod-with-eip	Yes	false	Whether to allocate an EIP with a pod and bind the EIP to the pod	false or true
  yangtse.io/eip-network-type	No	5_bgp	EIP type	5_bgp The specific type varies with regions. For details, see the EIP console.
  yangtse.io/eip-bandwidth-id	Mandatory when a shared bandwidth is used	None	ID of an existing bandwidth If this parameter is not specified, the EIP with a dedicated bandwidth is used by default. For details about how to configure parameters for an EIP with a dedicated bandwidth, see Table 1. Only the yangtse.io/eip-network-type field can be specified concurrently, and this field is optional.	None

Using an Existing EIP for a Pod

If you configure the yangtse.io/eip-id annotation when creating a pod, the EIP will be automatically bound to the pod.

• After an existing EIP is bound to a pod, CCE will automatically add the cluster ID, namespace, and pod name labels to the EIP.
• When a pod using an existing EIP is deleted, the EIP will be retained. CCE will automatically delete the labels for the cluster ID, namespace, and pod name that were added when the EIP was bound.

The following example shows how to create a Deployment named nginx with a single pod with an EIP automatically bound.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
      annotations:
        yangtse.io/eip-id: <eip_id> # ID of an existing EIP
    spec:
      containers:
        - name: container-0
          image: nginx:alpine
          resources:
            limits:
              cpu: 100m
              memory: 200Mi
            requests:
              cpu: 100m
              memory: 200Mi
      imagePullSecrets:
        - name: default-secret

Checking Whether the EIP Bound to the Pod Is Available

After an EIP is allocated to a pod, the container networking controller binds the EIP to the pod and writes the allocation result back to the pod's yangtse.io/allocated-ipv4-eip annotation. The startup time of the pod's service containers may be earlier than the time when the EIP allocation result is written back.

You can configure an init container for the pod, associate the yangtse.io/allocated-ipv4-eip annotation with the init container through a downwardAPI volume, and check whether the EIP has been allocated in the init container. You can configure the init container as follows:

apiVersion: v1
kind: Pod
metadata:
  name: example
  annotations:
    yangtse.io/pod-with-eip: "true"  
    yangtse.io/eip-bandwidth-size: "5" 
    yangtse.io/eip-network-type: 5_bgp
    yangtse.io/eip-charge-mode: bandwidth
    yangtse.io/eip-bandwidth-name: "xxx"
spec:
  initContainers:
  - name: init
    image: busybox:latest
    command: ['timeout', '60', 'sh', '-c', "until grep -E '[0-9]+' /etc/eipinfo/allocated-ipv4-eip; do echo waiting for allocated-ipv4-eip; sleep 2; done"]
    volumeMounts:
        - name: eipinfo
          mountPath: /etc/eipinfo
  volumes:
    - name: eipinfo
      downwardAPI:
        items:
          - path: "allocated-ipv4-eip"
            fieldRef:
              fieldPath: metadata.annotations['yangtse.io/allocated-ipv4-eip']
...