Static IP Address Usage

Last updated: 2021-04-13 10:20:05

    Overview

    This mode is suitable for scenarios that rely on container static IP addresses, for example, migrating a traditional architecture to a container platform and performing security policy restrictions on IP addresses. It is not recommended to use the static IP address mode for services without IP limits.

    Features and Limitations

    • The static IP address is achieved by retaining the associated IP address when the Pod is terminated, or keeping the IP unchanged when the Pod is migrated.
    • Pods in a cluster can be in different subnets, but Pods with static IP addresses cannot be scheduled across node availability zones and across subnets.
    • The IP address of Pod can automatically associate with EIP, thus Pod can be accessed via internet.
    • For the static IP addresses with shared ENI, when the Pod with static IP address is terminated, its IP address is only retained in the cluster. If other clusters or services (such as CVM, CDB, CLB) use the same subnet, the retained static IP address may be occupied, and the Pod will be unable to obtain the IP address when it being restarted. Please ensure that the container subnet of this mode is exclusively used.

    Usage

    You can enable the static IP address using either of the following methods:

    • Select VPC-CNI with static IP address when creating a cluster
    • Enable VPC-CNI with static IP address for GlobalRouter mode

    Selecting VPC-CNI with static IP address when creating a cluster

    Note:

    If you use this method to enable VPC-CNI, when you create a workload on the console or through YAML, all Pods will use ENIs by default.

    1. Log in to the TKE console and click Cluster in the left sidebar.
    2. On the "Cluster Management" page, click Create above the cluster list.
    3. On Create Cluster page, select VPC-CNI for Container Network Add-on.
    4. Check Enable Support for Static Pod IP, as shown in the figure below:

    Enabling VPC-CNI with static IP address for GlobalRouter mode

    Enabling VPC-CNI for the existing clusters

    Note:

    • Enable VPC-CNI Mode with static IP address for GlobalRouter, that is, when creating a cluster, you select the Global Router network add-on, and then enable the VPC-CNI mode (both modes can be used at the same time by default) on the basic information page of the cluster.
    • If you use this method to enable VPC-CNI, the Pods cannot use ENIs by default.
    1. Log in to the TKE console and select Cluster in the left sidebar.
    2. On Cluster Management page, select a cluster ID that needs to enable VPC-CNI and go to its details page.
    3. On the cluster details page, click Basic Information on the left.
    4. In the Node and Network Information section, enable VPC-CNI mode.
    5. Select the subnet and set the IP Reclaiming Policy in the pop-up window, as shown in the figure below:

      Note:

      • For scenarios that use static IP addresses, when enabling VPC-CNI, you need to set the IP reclaiming policy to specify when to reclaim the IP addresses after Pods are terminated.
      • Pods with non-static IP addresses are not affected by these settings because their IP addresses are immediately released upon Pod termination. These IP addresses are not returned to the VPC, but returned to the IP address pool managed by the container.
    6. Click Submit.

    Creating StatefulSets with static Pod IP addresses

    In GlobalRouter mode with VPC-CNI enabled, if you have applications to deploy in TKE, which need to use the static Pod IP addresses, you can create a StatefulSets with static IP addresses. Pod created by this type of StatefulSet are assigned with an actual IP address in the VPC through an ENI. The IP addresses are assigned by TKE VPC-CNI add-on. So that when the Pod is restarted or migrated, the IP address can be unchanged.

    By using StatefulSets with static IP addresses, you can:

    • Authorize based on source IP addresses.
    • Review processes based on IP addresses.
    • Query logs based on Pod IP addresses.

    Note:

    When StatefulSets with static IP addresses are used, the static IP addresses survive only within the lifecycle of their StatefulSets.

    You can create the static IP address using either of the following methods:

    • Creating StatefulSets with Static IP Addresses via TKE console
    1. Log in to the TKE console and select Cluster in the left sidebar.
    2. Select a cluster ID that needs to use the static IP address and go to its management page.
    3. Choose Workload > StatefulSet to go to the cluster management page of StatefulSet.
    4. Click Create to view Number of instances, as shown below:
    5. Click Advanced Settings and set StatefulSet parameters as needed. The key parameters are as follows:
    • Network mode: select Enable VPC-CNI mode.

      • IP address range: currently, only the Random value is supported.
      • Static pod IP: select Enable.
    • Creating via YAML

      apiVersion: apps/v1
      kind: StatefulSet
      metadata:
      labels:
        k8s-app: busybox
      name: busybox
      namespace: default
      spec:
      replicas: 3
      selector:
        matchLabels:
          k8s-app: busybox
          qcloud-app: busybox
      serviceName: ""
      template:
        metadata:
          annotations:
            tke.cloud.tencent.com/networks: "tke-route-eni"
            tke.cloud.tencent.com/vpc-ip-claim-delete-policy: Never
          creationTimestamp: null
          labels:
            k8s-app: busybox
            qcloud-app: busybox
        spec:
          containers:
          - args:
            - "10000000000"
            command:
            - sleep
            image: busybox
            imagePullPolicy: Always
            name: busybox
            resources:
              limits:
                tke.cloud.tencent.com/eni-ip: "1"
              requests:
                tke.cloud.tencent.com/eni-ip: "1" 
      
    • spec.template.annotations: tke.cloud.tencent.com/networks: "tke-route-eni" indicates that the Pod uses the VPC-CNI mode with shared ENI. If you use the VPC-CNI mode with independent ENI, please modify the value to "tke-direct-eni".

    • spec.template.annotations: to create Pods in VPC-CNI mode, you need to set the annotation tke.cloud.tencent.com/vpc-ip-claim-delete-policy. Its default value is “Immediate”, that is, when a Pod is terminated, the associated IP address is also terminated. To use a static IP address, set it to “Never”, that is, a Pod is terminated, but the associated IP address will be retained. When a Pod with the same name as the terminated Pod is pulled the next time, the original IP address is used.

    • spec.template.spec.containers.0.resources: to create Pods with shared ENI in VPC-CNI mode, you need to add "requests" and "limits", that is, tke.cloud.tencent.com/eni-ip. If you are using the VPC-CNI mode with independent ENI, add tke.cloud.tencent.com/direct-eni.