Create an L2 template for a Kubernetes manager node

Warning

Avoid modifying existing L2 templates and subnets that the deployed machines use. This prevents multiple clusters failures caused by unsafe changes. The list of risks posed by modifying L2 templates includes:

• Services running on hosts cannot reconfigure automatically to switch to the new IP addresses and/or interfaces.

• Connections between services are interrupted unexpectedly, which can cause data loss.

• Incorrect configurations on hosts can lead to irrevocable loss of connectivity between services and unexpected cluster partition or disassembly.

Note

Starting from MOSK 22.3, modification of L2 templates in use is prohibited in the API to prevent accidental cluster failures due to unsafe changes.

According to the reference architecture, the Kubernetes manager nodes in the MOSK cluster must be connected to the following networks:

• PXE network

• LCM network

• Kubernetes workloads network

Caution

If you plan to deploy MOSK cluster with the compact control plane option, skip this section entirely and proceed with Create an L2 template for a MOSK controller node.

To create an L2 template for Kubernetes manager nodes:

1. Create or open the mosk-l2templates.yml file that contains the L2 templates you are preparing.

2. Add an L2 template using the following example. Adjust the values of specific parameters according to the specifications of your environment.

   L2 template example

   apiVersion: ipam.mirantis.com/v1alpha1
   kind: L2Template
   metadata:
     labels:
       kaas.mirantis.com/provider: baremetal
       kaas.mirantis.com/region: region-one
       cluster.sigs.k8s.io/cluster-name: <MOSKClusterName>
     name: k8s-manager
     namespace: <MOSKClusterNamespace>
   spec:
     autoIfMappingPrio:
     - provision
     - eno
     - ens
     - enp
     clusterRef: <MOSKClusterName>
     l3Layout:
     - subnetName: lcm-nw
       scope: namespace
     - subnetName: k8s-pods-subnet
       scope: namespace
     npTemplate: |-
       version: 2
       ethernets:
         {{nic 0}}:
           dhcp4: false
           dhcp6: false
           match:
             macaddress: {{mac 0}}
           set-name: {{nic 0}}
           mtu: 9000
         {{nic 1}}:
           dhcp4: false
           dhcp6: false
           match:
             macaddress: {{mac 1}}
           set-name: {{nic 1}}
           mtu: 9000
         {{nic 2}}
           dhcp4: false
           dhcp6: false
           match:
             macaddress: {{mac 2}}
           set-name: {{nic 2}}
           mtu: 9000
         {{nic 3}}:
           dhcp4: false
           dhcp6: false
           match:
             macaddress: {{mac 3}}
           set-name: {{nic 3}}
           mtu: 9000
       bonds:
         bond0:
           mtu: 9000
           parameters:
             mode: 802.3ad
           interfaces:
           - {{nic 0}}
           - {{nic 1}}
       vlans:
         k8s-lcm-v:
           id: 403
           link: bond0
           mtu: 9000
         k8s-pods-v:
           id: 408
           link: bond0
           mtu: 9000
       bridges:
         k8s-lcm:
           interfaces: [k8s-lcm-v]
           addresses:
           - {{ ip "k8s-lcm:lcm-nw" }}
           nameservers:
             addresses: {{nameservers_from_subnet "lcm-nw"}}
           gateway4: {{ gateway_from_subnet "lcm-nw" }}
         k8s-pods:
           interfaces: [k8s-pods-v]
           addresses:
           - {{ip "k8s-pods:k8s-pods-subnet"}}
           mtu: 9000
   

3. Proceed with Create an L2 template for a MOSK controller node. The resulting L2 template will be used to render the netplan configuration for the managed cluster machines.