Configuring a Cluster

If you have two Netvisor One switches, and want them to work together to provide networking services in the event one of the switches fails, the switches must be members of the same fabric, and you must configure them as a cluster.

You configure one node as a primary node and the other node as a secondary. This reference is asymmetric, as these assignments do not change unless you explicitly configure them differently.

When you create a cluster configuration, you specify the nodes as cluster-node-1 and cluster-node-2. These assignments do not change unless you explicitly change them.

Cluster-node-1 is the primary node and cluster-node-2 is the secondary node. These roles are used to add asymmetry to some protocols. This reference is asymmetric.

A cluster-link contains the port or ports directly connecting the two cluster nodes together. If there are more than one port, this refers to the trunk (LAG) of those ports.

VLAN 4094 is a reserved VLAN used for cluster synchronization traffic. It is added to the in-band interface port and cluster-link automatically when you create the cluster configuration.

Netvisor One detects cluster-links using an extra data set send in LLDP messages. When a cluster-link is detected, VLAN 4094 is automatically added to it.

Netvisor One performs cluster synchronization over the control network of the fabric. For the in-band interface, synchronization uses the clust4094 vNIC on VLAN 4094 over the cluster-links. For management, this is performed on the management interface.

Cluster synchronization uses keep-alive messages to detect if the peer cluster node is online. Cluster synchronization messages contain the following information:

  • Version
  • State — online, coming-online, etc.
  • Sequence number
  • Flags
  • Uptime
  • STP version number
  • Status version number

The state synchronization is online or offline state of the cluster. Additionally, version numbers are exchanged so messages are adjusted to ensure backward compatibility. Each cluster node sends sync messages to the other node every 2 seconds. If a node misses three synchronization messages in a row, the cluster goes offline. When a node comes online, it triggers the following behavior:

  • A resend of all status updates to the peer
  • A resynchronization of all VLAGs
  • The transition of STP from independent mode to cluster mode.

To set up a cluster of two switches, pleiades4 and pleiades6, you must verify that they are members of the existing fabric:

CLI (network-admin@switch) > fabric-node-show layout vertical

id:                     184549641

name:                   pleiades4

fab-name:               corp-fab

fab-id:                 b000109:5695af4f

cluster-id:             0:0

local-mac:              3a:7f:b1:43:8a:0f

fabric-network:         in-band

control-network:        in-band


mgmt-mac:               ec:f4:bb:fe:06:20



in-band-mac:            3a:7f:b1:43:8a:0f

in-band-vlan:           0


fab-tid:                1

cluster-tid:            0

out-port:               0

version:                2.4.204009451,#47~14.04.1-Ubuntu

state:                  online

firmware-upgrade:       not-required

device-state:           ok

ports:                  104


To create a cluster configuration, use the following command:

CLI (network-admin@switch) > cluster-create name cluster1 cluster-node-1 onvlnvOS-switch1 cluster-node-2 onvlnvOS-switch2

To verify the status of the cluster, use the cluster-show command:

CLI (network-admin@switch) > cluster-show

name        state      cluster-node-1     cluster-node-2

---------   -------    ---------------    --------------

cluster1    online     corp-switch1   corp-switch2


To replace a failed cluster node, use the cluster-repeer command. However, you must evict the failed node from the fabric, and then run the cluster-repeer command on an active node after replacing the failed node.

To display information about the cluster, use the cluster-info command:

CLI (network-admin@switch) > cluster-info format all layout vertical

name:           cluster-leaf

state:          online

cluster-node-1: draco01

cluster-node-2: draco02

tid:            2

mode:           master

ports:          69-71,129

remote-ports:   69-71,128

If you want to connect the cluster nodes to an uplink switch, you must configure a VLAG between the ports on the cluster nodes and the uplink switch.

For example, if corp-switch1 has port 53 connected to the uplink switch and corp-switch2 has port 19 connected to the uplink switch, create a VLAG by executing the vlag-create command on either of the switches:

CLI (network-admin@switch) > VLAG-create name VLAG-uplink local-port 53 peer-switch switch1 peer-port 19

This example assumes that you have entered the command on switch2.

To verify the configuration, use the following command:

CLI (network-admin@switch) > vlag-show





















Note: Before you can create a VLAG, you must configure the two switches in a cluster.

More Information on vLAGs

Netvisor One uses vLAG synchronization to coordinate Active-Standby and Active-Active vLAGs using the following rules:

Active-Standby vLAGs

  • Per vLAG, only one side, ports in a cluster node, can be up at any one time. The other side is in standby.
  • In a competing environment, the side with a longer connection time remains up and the other side is disabled.

Active-Active vLAGs

  • If and only if both sides of the vLAG are up and the ingress port is the cluster link, Netvisor One adds port egress rules to drop any packets egressing the vLAG port.
  • Active-Active vLAGs also require Layer 2 entry synchronization.

Modifying LACP Mode on an Existing VLAG Configuration

You can modify the LACP mode on an existing VLAG configuration:

  • Support LACP Mode changes on configured VLAGs.
  • No restrictions for configuring LACP passive mode on VLAGs.
  • Save VLAG configuration after updating it.
  • Restore the port configuration after deleting a VLAG

CLI (network-admin@switch) > vlag-modify

name name-string

Specify the VLAG name. 


If you specify the parameter, failover-move-L2, Netvisor One sends gratuitous ARPs.

lacp-mode off|passive|active

Specify the LACP mode as off, passive or active.

lacp-timeout slow|fast

Specify the LACP timeout as slow (30 seconds) or fast (4 seconds).

lacp-fallback bundle|individual

Specify the LACP fallback mode as individual or bundled.

lacp-fallback-timeout seconds

Specify the LACP fallback timeout in seconds. The default is 50