Limiting failovers caused by route monitors in non-INC mode

In an HA configuration in non-INC mode, if route monitors fail on both nodes, failover happens every 180 seconds until one of the nodes is able to reach all of the routes monitored by the respective route monitors.

However, for a node, you can limit the number of failovers for a given interval by setting the Maximum Number of Flips and Maximum Flip Time parameters on the nodes. When either limit is reached, no more failovers occur, and the node is assigned as primary (but node state as NOT UP) even if any route monitor fails on that node. This combination of HA state as Primary and Node state as NOT UP is called Stick Primary state.

If the node is then able to reach all of the monitored routes, the next monitor failure triggers resetting of the Maximum Number of Flips and Maximum Flip Time parameters on the node and starting the time specified in the Maximum Flip Time parameter.

These parameters are set independently on each node and therefore are neither propagated nor synchronized.

  • Parameters for limiting the number of failovers

    Maximum Number of Flips (maxFlips)

    Maximum number of failovers allowed, within the Maximum Flip Time interval, for the node in HA in non INC mode, if the failovers are caused by route-monitor failure.

    Maximum Flip Time ( maxFlipTime )

    Amount of time, in seconds, during which failovers resulting from route-monitor failure are allowed for the node in HA in non INC mode.

To limit the number of failovers by using the command line interface

At the command prompt, type:

  • set HA node [-maxFlips < positive_integer>] [-maxFlipTime <positive_integer>]
  • show HA node [< id>]

To limit the number of failovers by using the GUI

  1. Navigate to System > High Availability and, on the Nodes tab, open the local node.
  2. Set the following parameters:
  • Maximum Number of Flips
  • Maximum Flip Time
    > set ha node -maxFlips 30 -maxFlipTime 60
    Done
    > sh ha node
    1) Node ID: 0
    IP: 10.102.169.82 (NS)
    Node State: UP
    Master State: Primary
    Fail-Safe Mode: OFF
    INC State: DISABLED
    Sync State: ENABLED
    Propagation: ENABLED
    Enabled Interfaces : 1/1
    Disabled Interfaces : None
    HA MON ON Interfaces : 1/1
    Interfaces on which heartbeats are not seen :None
    Interfaces causing Partial Failure:None
    SSL Card Status: NOT PRESENT
    Hello Interval: 200 msecs
    Dead Interval: 3 secs
    Node in this Master State for: 0:4:24:1 (days:hrs:min:sec)

    2) Node ID: 1
    IP: 10.102.169.81
    Node State: UP
    Master State: Secondary
    Fail-Safe Mode: OFF
    INC State: DISABLED
    Sync State: SUCCESS
    Propagation: ENABLED
    Enabled Interfaces : 1/1
    Disabled Interfaces : None
    HA MON ON Interfaces : 1/1
    Interfaces on which heartbeats are not seen : None
    Interfaces causing Partial Failure: None
    SSL Card Status: NOT PRESENT

    Local node information:
    Configured/Completed Flips: 30/0
    Configured Flip Time: 60
    Critical Interfaces: 1/1

    Done

SNMP Alarm for Sticky Primary State

Enable HA-STICKY-PRIMARY SNMP alarm in a node of a high availability set up if you want to be alerted of the node becoming sticky primary. When the node becomes sticky primary, it alerts by generating a trap message (stickyPrimary (1.3.6.1.4.1.5951.1.1.0.138)) and sends it to all the configured SNMP trap destinations. For more information about configuring SNMP alarms and trap destinations, see onfiguring the NetScaler to Generate SNMPv1 and SNMPv2 Traps.

Frequently Asked Questions

Consider an example of a high availability setup of two NetScaler appliances NS-1 and NS-2 in non-INC mode. Maximum numbers of flips and maximum flip time in both the nodes have been set with the same values.

The following table lists the settings used in this example: |Entity|Detail| |–|–| |IP address of NS-1|10.102.173.211| |IP address of NS-2|10.102.173.212| |Maximum number of flips|2| |Maximum flip time|200|

For information about the maximum number of flips and maximum flip time settings, refer to the pdf.

Limiting failovers caused by route monitors in non-INC mode