Thursday, February 21, 2013

How to configure preempt and priority NSRP options. How to force one firewall to be the preferred master.

SUMMARY:
How to force a device in the cluster to be the preferred master?
PROBLEM OR GOAL:
One of the firewalls of the cluster needs to be the preferred master.  How do you configure this?
SOLUTION:
The NSRP parameters preempt and priority are used to control the preferred master.  

Step 1.  On the preferred master, enable 'preempt' mode and assign a lower priority to the firewall in the cluster.
Configuration example:
Important:  The device with the lowest priority will be the preferred master.
nsisg1000(M)-> set nsrp vsd-group id 0 priority 50  <- To assign priority to device. By default the priority is 100
nsisg1000(M)-> 
set nsrp vsd-group id 0 preempt      <- To enable preempt mode

To verify configuration:
nsisg1000(M)get nsrp vsd-group 
VSD group info:
init hold time: 5
heartbeat lost threshold: 3
heartbeat interval: 1000(ms)
master always exist: disabled
group priority preempt holddown inelig   master       PB other members
    0       50 yes            3 no       myself 12090607 
total number of vsd groups: 1
Total iteration=375750,time=399053148,max=6586,min=274,average=1062
 
Step 2.  On the other firewall, the preferred backup, only the priority needs to be specified.  Assign the priority to be a higher value than the priority of the preferred master.
nsisg1000(B)-> set nsrp vsd-group id 0 priority 100  

Note:  A preempt hold-time may also be configured on the preferred master.  Refer to the Concepts & Examples ScreenOSReference Guide: Vol 11, High Availability for more information. 

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