L2 template example with bonds and bridges

This section contains an exemplary L2 template that demonstrates how to set up bonds and bridges on hosts for your managed clusters as described in Create L2 templates.

Caution

Use of a dedicated network for Kubernetes pods traffic, for external connection to the Kubernetes services exposed by the cluster, and for the Ceph cluster access and replication traffic is available as Technology Preview. Use such configurations for testing and evaluation purposes only. For the Technology Preview feature definition, refer to Technology Preview features.

The following feature is still under development and will be announced in one of the following Container Cloud releases:

  • Switching Kubernetes API to listen to the specified IP address on the node

Kubernetes LCM network

The Kubernetes LCM network connects LCM agents running on nodes to the LCM API of the management or regional cluster. It is also used for communication between kubelet and Kubernetes API server inside a Kubernetes cluster. The MKE components use this network for communication inside a swarm cluster.

To configure each node with an IP address that will be used for LCM traffic, use the npTemplate.bridges.k8s-lcm bridge in the L2 template, as demonstrated in the example below.

Starting from Container Cloud 2.16.0, you can use any interface name for the LCM network traffic. The Subnet objects for the LCM network must have the ipam/SVC-k8s-lcm label. For details, see Service labels and their life cycle.

Caution

In Container Cloud 2.15.0, the configuration of LCM network by use of the k8s-lcm bridge is mandatory. Addresses for the LCM network are assigned from the Subnet objects marked with the ipam/SVC-k8s-lcm label. Use of ipam/SVC-k8s-lcm label for the LCM network Subnet objects is mandatory. For details, see Service labels and their life cycle.

As defined in Host networking, the LCM network can be collocated with the PXE network.

Dedicated network for the Kubernetes pods traffic

If you want to use a dedicated network for Kubernetes pods traffic, configure each node with an IPv4 address that will be used to route the pods traffic between nodes. To accomplish that, use the npTemplate.bridges.k8s-pods bridge in the L2 template, as demonstrated in the example below. As defined in Host networking, this bridge name is reserved for the Kubernetes pods network. When the k8s-pods bridge is defined in an L2 template, Calico CNI uses that network for routing the pods traffic between nodes.

Dedicated network for the Kubernetes services traffic (MetalLB)

You can use a dedicated network for external connection to the Kubernetes services exposed by the cluster. If enabled, MetalLB will listen and respond on the dedicated virtual bridge. To accomplish that, configure each node where metallb-speaker is deployed with an IPv4 address. Both the MetalLB IP address ranges and the IP addresses configured on those nodes must fit in the same CIDR.

Use the npTemplate.bridges.k8s-ext bridge in the L2 template, as demonstrated in the example below. This bridge name is reserved for the Kubernetes external network. The Subnet object that corresponds to the k8s-ext bridge must have explicitly excluded the IP address ranges that are in use by MetalLB.

Dedicated network for the Ceph distributed storage traffic

You can configure dedicated networks for the Ceph cluster access and replication traffic. Set labels on the Subnet CRs for the corresponding networks, as described in Create subnets. Container Cloud automatically configures Ceph to use the addresses from these subnets. Ensure that the addresses are assigned to the storage nodes.

Use the npTemplate.bridges.ceph-cluster and npTemplate.bridges.ceph-public bridges in the L2 template, as demonstrated in the example below. These names are reserved for the Ceph cluster access (public) and replication (cluster) networks.

The Subnet objects used to assign IP addresses to these bridges must have corresponding labels ipam/SVC-ceph-public for the ceph-public bridge and ipam/SVC-ceph-cluster for the ceph-cluster bridge.

Example of an L2 template with interfaces bonding

apiVersion: ipam.mirantis.com/v1alpha1
kind: L2Template
metadata:
  name: test-managed
  namespace: managed-ns
spec:
  clusterRef: managed-cluster
  autoIfMappingPrio:
    - provision
    - eno
    - ens
    - enp
  l3Layout:
    - subnetName: demo-lcm
      scope:      namespace
    - subnetName: demo-pods
      scope:      namespace
    - subnetName: demo-ext
      scope:      namespace
    - subnetName: demo-ceph-cluster
      scope:      namespace
    - subnetName: demo-ceph-public
      scope:      namespace
  npTemplate: |
    version: 2
    ethernets:
      {{nic 2}}:
        dhcp4: false
        dhcp6: false
        match:
          macaddress: {{mac 2}}
        set-name: {{nic 2}}
      {{nic 3}}:
        dhcp4: false
        dhcp6: false
        match:
          macaddress: {{mac 3}}
        set-name: {{nic 3}}
    bonds:
      bond0:
        interfaces:
          - {{nic 2}}
          - {{nic 3}}
        parameters:
          mode: 802.3ad
    vlans:
      k8s-ext-vlan:
        id: 1001
        link: bond0
      k8s-pods-vlan:
        id: 1002
        link: bond0
      stor-frontend:
        id: 1003
        link: bond0
      stor-backend:
        id: 1004
        link: bond0
    bridges:
      k8s-lcm:
        interfaces: [bond0]
        addresses:
          - {{ip "k8s-lcm:demo-lcm"}}
        gateway4: {{gateway_from_subnet "demo-lcm"}}
        nameservers:
          addresses: {{nameservers_from_subnet "demo-lcm"}}
      k8s-ext:
        interfaces: [k8s-ext-vlan]
        addresses:
          - {{ip "k8s-ext:demo-ext"}}
      k8s-pods:
        interfaces: [k8s-pods-vlan]
        addresses:
          - {{ip "k8s-pods:demo-pods"}}
      ceph-cluster:
        interfaces: [stor-backend]
        addresses:
          - {{ip "ceph-cluster:demo-ceph-cluster"}}
      ceph-public:
        interfaces: [stor-frontend]
        addresses:
          - {{ip "ceph-public:demo-ceph-public"}}