Create an L2 template for a Kubernetes manager node

Caution

Modification of L2 templates in use is only allowed with a mandatory validation step from the infrastructure operator to prevent accidental cluster failures due to 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.

For details, see Modify network configuration on an existing machine.

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

• PXE network

• API/LCM network (if you configure ARP announcement of the load-balancer IP address for the MOSK cluster API)

• LCM network (if you configure BGP announcement of the load-balancer IP address for the MOSK cluster API)

• 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 L2 templates for Kubernetes manager nodes:

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

2. Add L2 templates using the following example. Adjust the values of specific parameters according to the specifications of your environment, specifically the name of your project (namespace) and cluster, IP address ranges and networks, subnet names.

   L2 template example for Kubernetes manager node

   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: mosk-cluster-name
       rack1-mosk-manager: "true"
     name: rack1-mosk-manager
     namespace: mosk-namespace-name
   spec:
     autoIfMappingPrio:
     - provision
     - eno
     - ens
     - enp
     l3Layout:
     - subnetName: api-lcm
       scope: namespace
     - subnetName: rack1-k8s-pods
       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
             mii-monitor-interval: 100
           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:api-lcm" }}
           nameservers:
             addresses: {{nameservers_from_subnet "api-lcm"}}
           gateway4: {{ gateway_from_subnet "api-lcm" }}
         k8s-pods:
           interfaces: [k8s-pods-v]
           addresses:
           - {{ip "k8s-pods:rack1-k8s-pods"}}
           mtu: 9000
           routes:
             - to: 10.199.0.0/22 # aggregated address space for Kubernetes workloads
               via: {{gateway_from_subnet "rack1-k8s-pods"}}
   

   Note

   The kaas.mirantis.com/region label is removed from all MOSK objects in 24.1. Therefore, do not add the label starting with this release. On existing clusters updated to this release, or if added manually, MOSK ignores this label.

   Note

   Before MOSK 23.3, an L2 template requires clusterRef: <clusterName> in the spec section. Since MOSK 23.3, this parameter is deprecated and automatically migrated to the cluster.sigs.k8s.io/cluster-name: <clusterName> label.

   To create L2 templates for other racks, change the rack identifier in the names and labels above.

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