Feature Description

Cluster Manager (CM) high-availability (HA) is provided through keepalived and Distributed Replicated Block Device (DRBD).

Prior SMI releases used the externally routable ssh-ip address to configure keepalived and DRBD communications between the active and standby CM HA nodes. This model left potential for a split-brain situation should the externally routable network become unstable or unavailable.

To reduce this potential, the CM HA nodes can now be configured to use the internal network for keepalived and DRBD communications.

This is done using the following command in the CM configuration file:

nodes <node_name>
            cm ha-ip <internal_address> 

Below is an example of a configuration excerpt identifying the parameters for configuring internal and external addresses:

# The master-virtual-ip parameter contains the *internal* VIP address.
configuration master-virtual-ip 192.0.1.101
configuration master-virtual-ip-cidr 24
configuration master-virtual-ip-interface vlan1001
#
# The additional-master-virtual-ip parameter contains the details of the *externally* available VIP address.
configuration additional-master-virtual-ip 203.0.113.214
configuration additional-master-virtual-ip-cidr 26
configuration additional-master-virtual-ip-interface vlan3540
#
#The additional cm ha-ip parameter needs to be added with the *internal* IP of the node.
# 
Note

node-ip in a CM HA config points to the internal master-virtual-ip

 nodes cm1
            ssh-ip 203.0.113.212
            type k8s
            k8s node-type master
            k8s node-ip 192.0.1.101
            cm  ha-ip 192.0.1.59
            ...
            initial-boot netplan vlans vlan3540
                 addresses [ 203.0.113.212/26 ]
                 exit
            os netplan-additions ethernets eno1
                 addresses [ 192.200.0.29/8 ]
                 exit
            os netplan-additions vlans vlan1001
                 addresses [ 192.0.1.59/24 ]
                 exit
               exit
nodes cm2
    ssh-ip 203.0.113.213
    type k8s
    k8s node-type backup
    k8s node-ip 192.0.1.101
    cm ha-ip 192.0.1.60
    ...
    initial-boot netplan vlans vlan3540
    addresses [ 203.0.113.213/26 ]
    exit
    os netplan-additions ethernets eno1
    addresses [ 192.200.0.29/8 ]
    exit
    os netplan-additions vlans vlan1001
    addresses [ 192.0.1.60/24 ]
    exit
exit

Fore more information Cluster Manager HA deployments, refer to the UCC SMI Deployment Guide > SMI Cluster Manager – Deployment