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

!/usr/bin/perl

 

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

 

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

 

is completely down, due to a manual resume feature.

 

Applies only to pools with Global Availability and Manual Resume

 

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.

 

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

 

 

Logic for running command:

 

mode is "global availability"

 

AND

 

manual resume is "enable" )

 

AND

 

(

 

pool status = "red"

 

OR

 

( A member is pool has order 1 AND same member is "disabled" )

 

)

 

 

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

 

use strict;

 

use warnings;

 

use Getopt::Long;

 

 

my $usage = <<"END_USAGE";

 

$0 [--help | --?] [--debug]

 

Where: --help - Displays usage

 

--debug - Display debug information

 

END_USAGE

 

 

get command line options

 

my $help;

 

my $debug;

 

GetOptions(

 

"help|?" => \$help,

 

"debug" => \$debug

 

);

 

 

( print $usage and exit(0) ) if $help;

 

 

define system commands

 

my $snmpwalk_prog = '/usr/bin/snmpwalk -v2c -c baltimore localhost ';

 

my $pool_status = $snmpwalk_prog . 'gtmPoolStatusAvailState';

 

my $pool_order = $snmpwalk_prog . 'gtmPoolMbrOrder';

 

my $pool_enabled = $snmpwalk_prog . 'gtmPoolMbrEnabled';

 

my $pool_mode = $snmpwalk_prog . 'gtmPoolLbMode';

 

my $pool_manual_resume = $snmpwalk_prog . 'gtmPoolManualResume';

 

my %pools;

 

 

get pool member order number

 

print ("Command: $pool_order\n") if $debug;

 

open( my $pool_order_out, '-|', $pool_order )

 

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

 

while (<$pool_order_out>) {

 

my ( $pool, $ip, $port ) = / "(.*?)" [.]ipv4[.] "(.*?)" [.] (\d)+ /x;

 

my $member = $ip . '.' . $port;

 

my ($member_order) = / (\d) $ /x;

 

$pools{$pool}{MEMBER}{$member} = $member_order;

 

}

 

 

determine if pool member is enabled

 

print ("Command: $pool_enabled\n") if $debug;

 

open( my $pool_enabled_out, '-|', $pool_enabled )

 

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

 

while (<$pool_enabled_out>) {

 

my ( $pool, $ip, $port ) = / "(.*?)" [.]ipv4[.] "(.*?)" [.] (\d)+ /x;

 

my $member = $ip . '.' . $port;

 

my $is_enabled = / INTEGER: \s+ enable /x ? 1 : 0;

 

my $member_order = $pools{$pool}{MEMBER}{$member};

 

$pools{$pool}{MEMBER_ORDER}{$member_order} = $is_enabled;

 

}

 

 

get pool status

 

print ("Command: $pool_status\n") if $debug;

 

open( my $pool_status_out, '-|', $pool_status )

 

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

 

while (<$pool_status_out>) {

 

 

get pool

 

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

 

 

pool status

 

my ($pool_status) = / INTEGER: \s+ ( green | red ) /x;

 

$pools{$pool}{STATUS} = $pool_status;

 

}

 

 

get pool mode

 

print ("Command: $pool_mode\n") if $debug;

 

open( my $pool_mode_out, '-|', $pool_mode )

 

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

 

while (<$pool_mode_out>) {

 

 

get pool

 

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

 

 

pool status

 

my ($pool_mode) = / INTEGER: \s+ ( \w+ ) /x;

 

$pools{$pool}{MODE} = $pool_mode;

 

}

 

 

get manual resume

 

print ("Command: $pool_manual_resume\n") if $debug;

 

open( my $pool_manual_resume_out, '-|', $pool_manual_resume )

 

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

 

while (<$pool_manual_resume_out>) {

 

 

get pool

 

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

 

 

is pool manual resume

 

my $is_manual_resume = / INTEGER: \s+ enable /x ? 1 : 0;

 

$pools{$pool}{IS_MANUAL_RESUME} = $is_manual_resume;

 

}

 

 

loop through pools and run command as required

 

POOL:

 

for my $pool ( keys %pools ) {

 

 

my $status = $pools{$pool}{STATUS};

 

my $mode = $pools{$pool}{MODE};

 

my $is_manual_resume = $pools{$pool}{IS_MANUAL_RESUME};

 

my $is_member_one_disabled =

 

exists $pools{$pool}{MEMBER_ORDER}{1}

 

&& $pools{$pool}{MEMBER_ORDER}{1} == 0

 

? 1

 

: 0;

 

 

print(

 

"\n", $pool,

 

" mode:", $mode,

 

" is manual resume:", $is_manual_resume,

 

" status:", $status,

 

" is member 1 disabled:", $is_member_one_disabled,

 

"\n"

 

) if $debug;

 

 

run test

 

if ( $mode eq 'ga'

 

and $is_manual_resume

 

and ( $status eq 'red' or $is_member_one_disabled ) )

 

{

 

 

construct command

 

my $cmd =

 

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

 

 

if ($debug) {

 

print("\n===\nCommand: $cmd\n===\n");

 

next POOL;

 

}

 

 

run command

 

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

 

}

 

}

 

 

 

exit(0);