Configure IP Address Pools Using Eip

This document describes how to configure an Eip object, which functions as an IP address pool for OpenELB in BGP mode, Layer 2 mode, and VIP mode.

OpenELB assigns IP addresses in Eip objects to LoadBalancer Services in the Kubernetes cluster.

NOTE

Currently, OpenELB supports only IPv4 and will soon support IPv6.

Configure an Eip Object for OpenELB

You can create an Eip object to provide an IP address pool for OpenELB. The following is an example of the Eip YAML configuration:

apiVersion: network.kubesphere.io/v1alpha2
kind: Eip
metadata:
    name: eip-sample-pool
    annotations:
      eip.openelb.kubesphere.io/is-default-eip: "true"
spec:
    address: 192.168.0.91-192.168.0.100
    protocol: layer2
    interface: eth0
    disable: false
status:
    occupied: false
    usage: 1
    poolSize: 10
    used: 
      "192.168.0.91": "default/test-svc"
    firstIP: 192.168.0.91
    lastIP: 192.168.0.100
    ready: true
    v4: true

The fields are described as follows:

metadata:

  • name: Name of the Eip object.

  • annotations:

    • eip.openelb.kubesphere.io/is-default-eip: Whether the current Eip object is the default Eip object. The value can be "true" or "false". For each Kubernetes cluster, you can set only one Eip object as the default Eip object.

    When creating a Service, generally you need to add the lb.kubesphere.io/v1alpha1: openelb, protocol.openelb.kubesphere.io/v1alpha1: <mode>, and eip.openelb.kubesphere.io/v1alpha2: <Eip name> annotations to the Service to specify that OpenELB is used as the load balancer plugin, either the BGP, Layer 2, or VIP mode is used, and an Eip object is used as the IP address pool. However, if a default Eip object exists, you do not need to add the preceding annotations to the Service and the system automatically assigns an IP address from the default Eip object to the Service. Detailed rules about IP address assignment are as follows:

    The Service Uses OpenELB An Eip Object Is Specified A Default Eip Obejct Exists A Common Eip Object Exists IP Address Assigment
    No No No Irrelevant Pending
    No No Yes Irrelevant An IP address from the default Eip object
    Yes No No No Pending
    Yes No No Yes An IP adderss from a common Eip object
    Yes No Yes Irrelevant An IP address from the default Eip object
    Yes Yes Irrelevant No Pending
    Yes Yes Irrelevant Yes An IP address from the specified Eip object

spec:

  • address: One or more IP addresses, which will be used by OpenELB. The value format can be:

    • IP address, for example, 192.168.0.100.
    • IP address/Subnet mask, for example, 192.168.0.0/24.
    • IP address 1-IP address 2, for example, 192.168.0.91-192.168.0.100.

NOTE

IP segments in different Eip objects cannot overlap. Otherwise, a resource creation error will occur.
  • protocol: Specifies which mode of OpenELB the Eip object is used for. The value can be bgp, layer2, or vip. If this field is not specified, the default value bgp is used.

  • interface: NIC on which OpenELB listens for ARP or NDP requests. This field is valid only when protocol is set to layer2.

TIP

If the NIC names of the Kubernetes cluster nodes are different, you can set the value to can_reach:IP address (for example, can_reach:192.168.0.5) so that OpenELB automatically obtains the name of the NIC that can reach the IP address. In this case, you must ensure that the IP address is not used by Kubernetes cluster nodes but can be reached by the cluster nodes.
  • disable: Specifies whether the Eip object is disabled. The value can be:

    • false: OpenELB can assign IP addresses in the Eip object to new LoadBalancer Services.
    • true: OpenELB stops assigning IP addresses in the Eip object to new LoadBalancer Services. Existing Services are not affected.

status: Fields under status specify the status of the Eip object and are automatically configured. When creating an Eip object, you do not need to configure these fields.

  • occupied: Specifies whether IP addresses in the Eip object have been used up.

  • usage: Specifies how many IP addresses in the Eip object have been assigned to Services.

  • used: Specifies the used IP addresses and the Services that use the IP addresses. The Services are displayed in the Namespace/Service name format (for example, default/test-svc).

  • poolSize: Total number of IP addresses in the Eip object.

  • firstIP: First IP address in the Eip object.

  • lastIP: Last IP address in the Eip object.

  • v4: Specifies whether the address family is IPv4. Currently, OpenELB supports only IPv4 and the value can only be true.

  • ready: Specifies whether the Eip-associated program used for BGP/ARP/NDP routes publishing has been initialized. The program is integrated in OpenELB.