Configuring an EIP for a Pod

Scenario

In CCE Autopilot clusters, pods use elastic network interfaces or supplementary network interfaces for networking so you can directly bind EIPs to pods.

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

Constraints

To access a pod with an EIP bound from the Internet, you need to add security group rules to allow the Internet traffic to the pod.
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

When creating a pod, set the pod-with-eip annotation to true. An EIP will be automatically allocated and bound to the pod.

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: 250m
              memory: 500Mi
            requests:
              cpu: 250m
              memory: 500Mi
      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 bind an EIP to a 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 purchase page on the EIP console. For example, in the AP-Singapore region, if an EIP is billed by bandwidth, the bandwidth ranges from 1 Mbit/s to 2,000 Mbit/s; if an EIP is billed by traffic, the bandwidth ranges from 1 Mbit/s to 300 Mbit/s.
yangtse.io/eip-network-type	No	5_bgp	EIP type	The types vary by region. For details, see the EIP console. For example, the following options are available in the AP-Singapore region: 5_bgp: dynamic BGP
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: 250m
              memory: 500Mi
            requests:
              cpu: 250m
              memory: 500Mi
      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 bind an EIP to a pod	false or true
yangtse.io/eip-network-type	No	5_bgp	EIP type	5_bgp 5_union 5_sbgp The types vary by region. 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 parameter settings 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.	-

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']
...