Global load balance between two servers (failover), with no preemption

(honestly it was frustrating to not have this feature on the GTMS, and have to reinvent the wheel, for something as simple as enabling/disabling preemption on the pool members)

 

 

Anyway if you are ruining into the same issue this is what I did:

 

 

I end up building an auto resume script,that runs on all of the GTMs on a round robin every minute (on the cron job) or so for redenedancy.

 

 

The script uses snmpwalk to check the pools status on the localhost, and uses the GTM native tmsh command to bring only the pools that are completely down (on manual resume status) up.

 

 

Here it is:

 

 

!/usr/bin/perl

 

================================================================

 

$Id:$

 

$Revision:$ v1.0.0

 

$Author:$ Ahmed Khamari

 

$Date:$ 12-06-2011

 

================================================================

 

Description: Enable pool members that are manually disabled when their pool

 

is completely down, due to a manual resume feature.

 

Combining this with global availability, to Globally failover between two servers will

 

prevent possible flapping issues, if one of the servers goes unstable.

 

================================================================

 

Disclaimer:

 

This script is provided "AS IS", for non-commercial use, and you, its user, assume all risks when using it.

 

================================================================

 

 

my $snmpwalk_prog = '/usr/bin/snmpwalk';

 

my $snmpwalk_cmd =

 

$snmpwalk_prog . ' -v2c -c public localhost gtmPoolStatusAvailState';

 

verify SNMP walk is available

 

die "Program $snmpwalk_prog is not available" unless -x $snmpwalk_prog;

 

open( SNMPWALK, '-|', $snmpwalk_cmd )

 

or die "Failed to run command $snmpwalk_cmd : $!";

 

while () {

 

skip green

 

next if /INTEGER: green/;

 

get pool

 

my ($pool) = /"(.*?)"/;

 

construct command

 

my $cmd = "tmsh modify gtm pool $pool members modify { all { enabled }}";

 

run command

 

print "Running command: $cmd\n";

 

system($cmd) == 0 or die "$cmd failed";

 

}

 

exit(0);